Trial Outcomes & Findings for A Study of Amivantamab in Participants With Previously Treated Advanced or Metastatic Gastric or Esophageal Cancer (NCT NCT04945733)

Last Updated: 2024-09-19

Results Overview

ORR was defined as the percentage of participants who achieved a confirmed complete response (CR) or partial response (PR) as determined by investigator per RECIST version 1.1. As per RECIST version 1.1, CR was defined as disappearance of target and non-target lesions and normalization of tumor markers. Pathological lymph nodes must have short axis measures less than (\<)10 millimeter (mm). PR was defined as at least a 30 percent (%) decrease in the sum of measures (longest diameter for tumor lesions and short axis measure for nodes) of target lesions, taking as reference baseline sum of diameters. Non-target lesions must be non-progressive disease (PD). For non-target lesions, PD: unequivocal progression of existing non-target lesions. The appearance of one or more new lesions was also considered progression.

Recruitment status

TERMINATED

Study phase

PHASE2

Target enrollment

62 participants

Primary outcome timeframe

From start of the treatment (Day 1) up to 30 days after the last dose of study drug (up to 9 months)

Results posted on

2024-09-19

Participant Flow

The study was planned to be conducted in 2 cohorts: Phase 2a cohorts (including Phase 2a extension cohort) and Phase 2b expansion cohort in participants with previously treated advanced or metastatic gastric or esophageal cancer. However, due to study termination, no participants were enrolled in Phase 2a extension cohorts and Phase 2b cohorts. Hence the results were only presented for Phase 2a cohorts.

Participant milestones

Participant milestones
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Overall Study STARTED	29	30	3
Overall Study COMPLETED	25	24	3
Overall Study NOT COMPLETED	4	6	0

Reasons for withdrawal

Reasons for withdrawal
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Overall Study Physician Decision	1	3	0
Overall Study Withdrawal by Subject	3	3	0

Baseline Characteristics

A Study of Amivantamab in Participants With Previously Treated Advanced or Metastatic Gastric or Esophageal Cancer

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=29 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=30 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=3 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Total n=62 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Age, Categorical Between 18 and 65 years	13 Participants n=5 Participants	18 Participants n=7 Participants	2 Participants n=5 Participants	33 Participants n=4 Participants
Age, Categorical >=65 years	16 Participants n=5 Participants	12 Participants n=7 Participants	1 Participants n=5 Participants	29 Participants n=4 Participants
Age, Continuous	64 years STANDARD_DEVIATION 11.97 • n=5 Participants	62.7 years STANDARD_DEVIATION 10.35 • n=7 Participants	60 years STANDARD_DEVIATION 9 • n=5 Participants	63.2 years STANDARD_DEVIATION 10.97 • n=4 Participants
Sex: Female, Male Female	5 Participants n=5 Participants	6 Participants n=7 Participants	0 Participants n=5 Participants	11 Participants n=4 Participants
Sex: Female, Male Male	24 Participants n=5 Participants	24 Participants n=7 Participants	3 Participants n=5 Participants	51 Participants n=4 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	29 Participants n=5 Participants	30 Participants n=7 Participants	3 Participants n=5 Participants	62 Participants n=4 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Asian	29 Participants n=5 Participants	30 Participants n=7 Participants	3 Participants n=5 Participants	62 Participants n=4 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) White	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Region of Enrollment JAPAN	29 Participants n=5 Participants	30 Participants n=7 Participants	3 Participants n=5 Participants	62 Participants n=4 Participants

PRIMARY outcome

Timeframe: From start of the treatment (Day 1) up to 30 days after the last dose of study drug (up to 9 months)

Population: Response evaluable analysis set included all participants who received at least 1 dose of study treatment, met all eligibility criteria for the study and had a baseline and at least 1 post-baseline efficacy disease assessments, or had disease progression/death due to disease progression prior to the first post-baseline disease assessment.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=23 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=28 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=2 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors (RECIST) Version (v) 1.1	4.3 Percentage of Participants Interval 0.1 to 21.9	10.7 Percentage of Participants Interval 2.3 to 28.2	0 Percentage of Participants Interval 0.0 to 84.2	—

SECONDARY outcome

Timeframe: From start of the treatment (Day 1) up to 30 days after the last dose of study drug (up to 9 months)

DCR was defined as the percentage of participants achieving CR or PR or stable disease (SD) for at least 6 weeks as defined by RECIST version 1.1. As per RECIST version 1.1 CR was defined as disappearance of target and non-target lesions and normalization of tumor markers. Pathological lymph nodes must have short axis measures \<10 mm. PR was defined as \>=30% decrease in sum of measures (longest diameter for tumor lesions and short axis measure for nodes) of target lesions, taking as reference baseline sum of diameters. Non-target lesions must be non-PD. For non-target lesions, PD: unequivocal progression of existing non-target lesions. The appearance of one or more new lesions was also considered progression. SD was defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, and no appearance of new lesion(s).

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=23 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=28 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=2 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Disease Control Rate (DCR) Per RECIST Version 1.1	26.1 Percentage of Participants Interval 10.2 to 48.4	67.9 Percentage of Participants Interval 47.6 to 84.1	100 Percentage of Participants Interval 15.8 to 100.0	—

SECONDARY outcome

Timeframe: From the date of first documented response up to date of first documented PD or death (up to 9 months)

Population: Response evaluable analysis set included all participants who received at least 1 dose of study treatment, met all eligibility criteria for study and had a baseline and at least 1 post-baseline efficacy disease assessments, or had disease progression/death due to disease progression prior to first post-baseline disease assessment. Here 'N' (overall number of participants analyzed) = participants evaluable for this outcome measure.

DOR was defined as time between date of first documented response (CR/PR) and date of first documented progression or death, whichever occurred first. CR was defined as disappearance of target and non-target lesions and normalization of tumor markers. Pathological lymph nodes short axis measures \<10 mm. PR was defined as \>=30% decrease in sum of measures (tumor lesions-longest diameter and nodes-short axis) of target lesions, taking as reference baseline sum of diameters. Non-target lesions must be non-PD. For non-target lesions, PD: unequivocal progression of existing non-target lesions. The appearance of one or more new lesions was also considered progression. There was no participant who had event (CR/PR) in Phase 2a EC higher dose cohort, hence data could not be collected and analyzed for this cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=1 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=3 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Duration of Response (DOR) as Per RECIST Version 1.1	NA Months Here, 'NA' signifies that median, lower and upper limit of 95% confidence interval (CI) could not be calculated due to less number of participants with events.	2.86 Months Interval 2.79 to Here, 'NA' signifies that upper limit of 95% CI could not be calculated due to less number of participants with events.	—	—

SECONDARY outcome

Timeframe: From first dose of study treatment until first documentation of CR or PR (up to 9 months)

TTR was defined as time from date of first amivantamab administration to date of achieving objective response (CR/PR) as assessed by investigator per RECIST v1.1 among participants who achieved objective response. Per RECIST v1.1, CR: disappearance of target and non-target lesions and normalization of tumor markers. Pathological lymph nodes must have short axis measures \<10 mm. PR: \>=30% decrease in sum of measures (longest diameter for tumor lesions and short axis measure for nodes) of target lesions, taking as reference baseline sum of diameters. Non-target lesions must be non-PD. For non-target lesions, PD: unequivocal progression of existing non-target lesions. The appearance of one or more new lesions was also considered progression. There was no participant who had event (CR/PR) in Phase 2a EC higher dose cohort, hence data could not be collected and analyzed for this cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=1 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=3 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Time to Response (TTR) as Per RECIST Version 1.1	1.45 Months Here, 'NA' signifies that lower and upper limit of 95% CI could not be calculated due to less number of participants with events.	1.41 Months Interval 1.41 to Here, 'NA' signifies that upper limit of 95% CI could not be calculated due to less number of participants with events.	—	—

SECONDARY outcome

Timeframe: From day of first dose (Day 1) until PD or death (up to 9 months)

Population: All treated analysis set included all participants who took at least 1 dose of study treatment.

PFS was defined as the time from the date of first dose of study drug until the date of objective disease progression or death (by any cause in the absence of progression), whichever comes first, based on investigator assessment using RECIST Version 1.1.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=29 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=30 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=3 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Progression Free Survival (PFS) as Per RECIST Version 1.1	1.45 Months Interval 1.41 to 1.48	4.11 Months Interval 2.1 to 4.17	2.99 Months Interval 1.41 to Here, 'NA' signifies that upper limit of 95% CI could not be calculated due to less number of participants with events.	—

SECONDARY outcome

Timeframe: From start of the treatment (Day 1) up to 30 days after last dose or start of new anticancer therapy, whichever occurred first (up to 9 months)

Population: The safety analysis set included all participants who took at least 1 dose of study treatment.

An adverse event (AE) was any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. TEAEs was defined as AEs occurring at or after first dose of study drug up to 30 days after last dose or until the start of new anticancer therapy, whichever occurred first. TEAEs were graded according to NCI-CTCAE v5.0. Grade 1- Mild; Grade 2- Moderate; Grade 3- Severe or medically significant but not immediately life-threatening; Grade 4- Life-threatening consequences; Grade 5- Death related to AE. All TEAEs including serious and non-serious events are reported in this outcome measure.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=29 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=30 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=3 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) Based on National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 5.0 Grade 1	4 Participants	3 Participants	1 Participants	—
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) Based on National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 5.0 Grade 2	14 Participants	17 Participants	1 Participants	—
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) Based on National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 5.0 Grade 3	8 Participants	9 Participants	1 Participants	—
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) Based on National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 5.0 Grade 4	0 Participants	0 Participants	0 Participants	—
Number of Participants With Treatment-Emergent Adverse Events (TEAEs) Based on National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 5.0 Grade 5	3 Participants	1 Participants	0 Participants	—

SECONDARY outcome

Timeframe: Pre-dose, 0, 24, 26, 48, 72, 96 and 168 hours post-dose on Day 1 of Cycle 1; pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Population: The pharmacokinetics (PK) analysis set included all participants who received at least 1 dose of study treatment and had at least 1 evaluable post-baseline measurement. Here 'N' (overall number of participants analyzed) = participants evaluable for this outcome measure and 'n' (number analyzed) = refers to participants evaluable at specified time points.

Cmax was defined as the maximum observed serum concentration of amivantamab. The concentrations of amivantamab were measured using a validated, specific, and sensitive enzyme-linked immunosorbent assay (ELISA) method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for Cmax was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=13 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=25 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Maximum Observed Serum Concentration (Cmax) for Amivantamab Cycle 1 Day 1	356 Micrograms per milliliter (mcg/mL) Standard Deviation 91.6	370 Micrograms per milliliter (mcg/mL) Standard Deviation 78.2	—	363 Micrograms per milliliter (mcg/mL) Standard Deviation 84.0
Maximum Observed Serum Concentration (Cmax) for Amivantamab Cycle 2 Day 1	820 Micrograms per milliliter (mcg/mL) Standard Deviation 221	866 Micrograms per milliliter (mcg/mL) Standard Deviation 196	—	845 Micrograms per milliliter (mcg/mL) Standard Deviation 202

SECONDARY outcome

Timeframe: Pre-dose, 0, 24, 26, 48, 72, 96 and 168 hours post-dose on Day 1 of Cycle 1; pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Population: The PK analysis set included all participants who received at least 1 dose of study treatment and had at least 1 evaluable post-baseline measurement. Here 'N' (overall number of participants analyzed) = participants evaluable for this outcome measure and 'n' (number analyzed) = refers to participants evaluable at specified time points.

Tmax was defined as the time to reach maximum observed serum concentration of amivantamab. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for Tmax was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=13 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=25 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Time to Reach Maximum Observed Serum Concentration (Tmax) for Amivantamab Cycle 1 Day 1	28.42 Hours (h) Interval 27.02 to 31.0	29.65 Hours (h) Interval 28.8 to 31.62	—	29.23 Hours (h) Interval 27.02 to 31.62
Time to Reach Maximum Observed Serum Concentration (Tmax) for Amivantamab Cycle 2 Day 1	4.23 Hours (h) Interval 2.42 to 24.63	2.53 Hours (h) Interval 2.27 to 4.53	—	3.46 Hours (h) Interval 2.27 to 24.63

SECONDARY outcome

Timeframe: Pre-dose, 0, 24, 26, 48, 72, 96 and 168 hours post-dose on Day 1 of Cycle 1 (each cycle was of 28 days)

AUC (0-168h) was defined as area under the serum concentration time-curve from time zero to the time point 168 hours. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for AUC (0-168h) was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=24 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Area Under the Curve From Time (0) to Time (168h) (AUC [0-168h]) for Amivantamab	30990 microgramshours/milliliter (mcghr/mL) Standard Deviation 8346	31548 microgramshours/milliliter (mcghr/mL) Standard Deviation 7854	—	31269 microgramshours/milliliter (mcghr/mL) Standard Deviation 7930

SECONDARY outcome

Timeframe: Pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Area under the serum concentration curve from time 0 to end of dosing interval (AUCtau), where dosing interval was 336 hours was reported. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for AUCtau was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=4 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=8 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Area Under the Curve From Time Zero to End of Dosing Interval (AUCtau) for Amivantamab	137806 microgramshours/milliliter (mcghr/mL) Standard Deviation 19006	162171 microgramshours/milliliter (mcghr/mL) Standard Deviation 45328	—	154049 microgramshours/milliliter (mcghr/mL) Standard Deviation 39369

SECONDARY outcome

Timeframe: Pre-dose at 0 hour: Days 8 and 15 of Cycle 1; Days 1 and 15 of Cycles 2, 3 and 4; Day 1 of Cycles 6 and 8 (each cycle was of 28 days)

Ctrough of amivantamab in GC and EC cohorts were reported. Ctrough was defined as pre-dose serum drug concentration. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]).

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=24 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=28 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=52 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 1 Day 8	119 Micrograms per milliliter (mcg/mL) Standard Deviation 34.9	136 Micrograms per milliliter (mcg/mL) Standard Deviation 45.1	128 Micrograms per milliliter (mcg/mL) Standard Deviation 40.5	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 1 Day 15	214 Micrograms per milliliter (mcg/mL) Standard Deviation 73.7	222 Micrograms per milliliter (mcg/mL) Standard Deviation 74.6	218 Micrograms per milliliter (mcg/mL) Standard Deviation 73.5	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 2 Day 1	308 Micrograms per milliliter (mcg/mL) Standard Deviation 99.5	342 Micrograms per milliliter (mcg/mL) Standard Deviation 77.4	327 Micrograms per milliliter (mcg/mL) Standard Deviation 88.5	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 2 Day 15	231 Micrograms per milliliter (mcg/mL) Standard Deviation 85.6	259 Micrograms per milliliter (mcg/mL) Standard Deviation 80.7	250 Micrograms per milliliter (mcg/mL) Standard Deviation 82.0	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 3 Day 1	166 Micrograms per milliliter (mcg/mL) Standard Deviation 86.6	234 Micrograms per milliliter (mcg/mL) Standard Deviation 58.5	217 Micrograms per milliliter (mcg/mL) Standard Deviation 70.3	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 3 Day 15	154 Micrograms per milliliter (mcg/mL) Standard Deviation 83.3	210 Micrograms per milliliter (mcg/mL) Standard Deviation 87.1	198 Micrograms per milliliter (mcg/mL) Standard Deviation 87.1	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 4 Day 1	105 Micrograms per milliliter (mcg/mL) Standard Deviation 73.2	236 Micrograms per milliliter (mcg/mL) Standard Deviation 82.8	210 Micrograms per milliliter (mcg/mL) Standard Deviation 95.4	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 4 Day 15	139.0 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	203 Micrograms per milliliter (mcg/mL) Standard Deviation 54.1	198 Micrograms per milliliter (mcg/mL) Standard Deviation 54.8	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 6 Day 1	122.3 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	190 Micrograms per milliliter (mcg/mL) Standard Deviation 35.7	173 Micrograms per milliliter (mcg/mL) Standard Deviation 44.7	—
Phase 2a Gastric Cancer and Esophageal Cancer Cohorts: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 8 Day 1	111.4 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	100.0 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	NA Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that, per planned analysis, data was not summarized where number of participants analyzed was less than 3. Only individual participant data was collected and analyzed which is reported in the first 2 arms.	—

SECONDARY outcome

Timeframe: Pre-dose at 0 hour: Day 15 of Cycle 1; Days 1 and 15 of Cycles 2 and 3; Day 1 of Cycles 6 and 8 (each cycle was of 28 days)

Population: The PK analysis set included all participants who received at least 1 dose of study treatment and had at least 1 evaluable post-baseline measurement. Here 'N' (overall number of participants analyzed) = the participants evaluable for this outcome measure and 'n' (number analyzed) = participants evaluable at specified time points. As planned participant wise data was collected and analyzed when "n" was less than (\<) 3.

Ctrough of amivantamab in phase 2a EC higher dose cohort was reported. Ctrough was defined as pre-dose serum drug concentration. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=2 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 2 Day 15: Participant 1	590 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 2 Day 15: Participant 2	604 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 3 Day 1: Participant 2	600 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 3 Day 15: Participant 1	460 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 6 Day 1: Participant 1	295 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 8 Day 1: Participant 1	314 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 1 Day 15: Participant 1	333 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 1 Day 15: Participant 2	337 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 2 Day 1: Participant 1	657 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 2 Day 1: Participant 2	779 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Esophageal Cancer Higher Dose Cohort: Serum Trough Concentrations (Ctrough) of Amivantamab Pre-dose Cycle 3 Day 1: Participant 1	433 Micrograms per milliliter (mcg/mL) Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—

SECONDARY outcome

Timeframe: Pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Population: The PK analysis set included all participants who received at least 1 dose of study treatment and had at least 1 evaluable post-baseline measurement. Here 'N' (overall number of participants analyzed) = the participants evaluable for this outcome measure and 'n' (number analyzed) = participants evaluable at specified row. As planned participant wise data was collected and analyzed when "n" was \<3.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=2 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Phase 2a Gastric Cancer Cohort: Terminal Elimination Half-Life (t1/2) for Amivantamab Participant 1	226.0 Hours Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—
Phase 2a Gastric Cancer Cohort: Terminal Elimination Half-Life (t1/2) for Amivantamab Participant 2	264.5 Hours Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	—	—	—

SECONDARY outcome

Timeframe: Pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Terminal elimination half-life (t1/2) was the time measured for the serum concentration of a drug to decrease by half of its initial concentration. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for EC cohort and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for t1/2 was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=7 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=9 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Phase 2a Esophageal Cancer and Overall Combined Cohorts: Terminal Elimination Half-Life (t1/2) for Amivantamab	254.7 Hours Standard Deviation 43.0	—	252.6 Hours Standard Deviation 38.7	—

SECONDARY outcome

Timeframe: Pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Clearance was a measure of the rate at which a drug was metabolized or eliminated by normal biological processes. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for CLss was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=4 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=8 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Apparent Clearance at Steady State (CLss) of Amivantamab	0.00775 Liters/hour (L/h) Standard Deviation 0.00122	0.00695 Liters/hour (L/h) Standard Deviation 0.00200	—	0.00722 Liters/hour (L/h) Standard Deviation 0.00176

SECONDARY outcome

Timeframe: Pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Volume of distribution was defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired serum concentration of a drug. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for Vss was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=1 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=6 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=7 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Apparent Volume of Distribution at Steady State (Vss) of Amivantamab	3.59 Liters Standard Deviation NA Here, 'NA' signifies that standard deviation could not be calculated due to single evaluable participant.	2.61 Liters Standard Deviation 1.04	—	2.75 Liters Standard Deviation 1.02

SECONDARY outcome

Timeframe: Pre-dose, 0, 24, 26, 48, 72, 96 and 168 hours post-dose on Day 1 of Cycle 1; pre-dose, 0, 2, 24, 48, 72, 168 and 336 hours post-dose on Day 1 of Cycle 2 (each cycle was of 28 days)

Accumulation ratio for AUC was calculated as AUC (0-336h) for Cycle 2 Day 1 divided by AUC (0-168h) for Cycle 1 Day 1. The concentrations of amivantamab were measured using a validated, specific, and sensitive ELISA method. Data for this outcome measure was planned to be collected and analyzed for each cancer type (GC and EC) and overall participants (GC and EC combined cohorts: Amivantamab \[1050/1400 mg\]). As planned, data for AR of AUCtau was not collected and analyzed for Phase 2a EC higher dose cohort.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=4 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=8 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) n=12 Participants Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Accumulation Ratio (AR) of AUCtau for Amivantamab	4.32 Ratio Standard Deviation 0.51	5.12 Ratio Standard Deviation 0.72	—	4.85 Ratio Standard Deviation 0.74

SECONDARY outcome

Timeframe: From start of the treatment (Day 1) up to 30 days after the last dose of study drug (up to 9 months)

Population: The immunogenicity analysis set included all participants who received at least 1 dose of study treatment and had at least 1 evaluable post-baseline measurement.

Number of participants with anti-amivantamab antibodies were reported. Serum samples were assessed for anti-drug antibodies.

Outcome measures

Outcome measures
Measure	Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg) n=26 Participants Participants with previously treated advanced or metastatic gastric/gastroesophageal junction cancer (GC) exhibiting varying degrees of epidermal growth factor receptor (EGFR), tyrosine-protein kinase mesenchymal-epithelial transition (MET), or both as determined by immunohistochemistry (IHC) received amivantamab 1050 milligrams (mg) for body weight less than (\<) 80 kilograms (kg) or 1400 mg for body weight greater than or equal to (\>=) 80 kg as an intravenous (IV) infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg/1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg) n=30 Participants Participants with previously treated advanced or metastatic esophageal cancer (EC) exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg) n=3 Participants Participants with previously treated advanced or metastatic EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1750 mg for body weight \<80 kg or 2100 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (1400 mg for body weight \<80 kg or 1750 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.	Overall: Phase 2a GC and EC Combined Cohorts: Amivantamab (1050/1400 mg) Participants with previously treated advanced or metastatic GC and EC exhibiting varying degrees of EGFR, MET, or both as determined by IHC received amivantamab 1050 mg for body weight \<80 kg or 1400 mg for body weight \>=80 kg as an IV infusion in each 28-day cycles. During Cycle 1, amivantamab was administered once weekly on Days 1, 8, 15 and 22 with the first dose split over Day 1 (350 mg) and Day 2 (700 mg for body weight \<80 kg or 1050 mg for body weight \>=80 kg). From Cycle 2 onwards, amivantamab was administered on Days 1 and 15 until disease progression, unacceptable toxicity, withdrawal of consent, initiation of subsequent anticancer therapy, lost to follow-up or death whichever comes first. Participants were followed up for safety up to 30 days after the last dose.
Number of Participants With Anti-Amivantamab Antibodies	0 Participants	0 Participants	0 Participants	—

Adverse Events

Phase 2a Gastric Cancer Cohort: Amivantamab (1050/1400 mg)

Serious events: 9 serious events

Other events: 28 other events

Deaths: 5 deaths

Phase 2a Esophageal Cancer Cohort: Amivantamab (1050/1400 mg)

Serious events: 7 serious events

Other events: 30 other events

Deaths: 2 deaths

Phase 2a Esophageal Cancer Higher Dose Cohort: Amivantamab (1750/2100 mg)

Serious events: 0 serious events

Other events: 3 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

Executive Medical Director

Janssen Pharmaceutical K.K.

Phone: 844-434-4210

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee If an investigator wishes to publish information from the study, a copy of the manuscript must be provided to the sponsor for review at least 60 days before submission for publication or presentation. If requested by the sponsor in writing, the investigator will withhold such publication for up to an additional 60 days to allow for filing of a patent application.
Publication restrictions are in place

Restriction type: OTHER