Trial Outcomes & Findings for A Study of Pembrolizumab (MK-3475) in Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) or Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) (MK-3475-B68) (NCT NCT04875195)

Last Updated: 2025-10-29

Results Overview

ORR was defined as the percentage of the participants who had complete response (CR) or partial response (PR) and was evaluated using computed tomography (CT) and metabolic imaging (fluorodeoxyglucose- positron emission tomography (FDG-PET)). CR is complete metabolic (no/minimal FDG uptake) and radiologic response (target lesions regress to ≤1.5 cm in longest transverse diameter of a lesion) and no new lesions. PR is partial metabolic (moderate/high FDG uptake) and radiologic response (≥50% decrease in sum of product diameters for multiple lesions of up to 6 target measurable nodes and extranodal sites, no increase in lesions, and spleen regressed by \>50% in length beyond normal). The percentage of participants treated with pembrolizumab Q6W, by cohort, rrcHL and rrPMBCL, who experienced CR or PR as assessed by investigator is presented.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

66 participants

Primary outcome timeframe

Up to approximately 30 months

Results posted on

2025-10-29

Participant Flow

Participant milestones

Participant milestones
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Overall Study STARTED	60	6
Overall Study COMPLETED	0	0
Overall Study NOT COMPLETED	60	6

Reasons for withdrawal

Reasons for withdrawal
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Overall Study Death	9	3
Overall Study Withdrawal by Subject	2	1
Overall Study Ongoing in study	49	2

Baseline Characteristics

A Study of Pembrolizumab (MK-3475) in Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) or Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) (MK-3475-B68)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=60 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) n=6 Participants Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Total n=66 Participants Total of all reporting groups
Age, Continuous	37.9 Years STANDARD_DEVIATION 16.1 • n=5 Participants	32.5 Years STANDARD_DEVIATION 8.6 • n=7 Participants	37.4 Years STANDARD_DEVIATION 15.6 • n=5 Participants
Sex: Female, Male Female	31 Participants n=5 Participants	4 Participants n=7 Participants	35 Participants n=5 Participants
Sex: Female, Male Male	29 Participants n=5 Participants	2 Participants n=7 Participants	31 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	6 Participants n=5 Participants	0 Participants n=7 Participants	6 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	50 Participants n=5 Participants	6 Participants n=7 Participants	56 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	4 Participants n=5 Participants	0 Participants n=7 Participants	4 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants	1 Participants n=7 Participants	1 Participants n=5 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
Race (NIH/OMB) Black or African American	5 Participants n=5 Participants	0 Participants n=7 Participants	5 Participants n=5 Participants
Race (NIH/OMB) White	49 Participants n=5 Participants	5 Participants n=7 Participants	54 Participants n=5 Participants
Race (NIH/OMB) More than one race	3 Participants n=5 Participants	0 Participants n=7 Participants	3 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	3 Participants n=5 Participants	0 Participants n=7 Participants	3 Participants n=5 Participants

PRIMARY outcome

Timeframe: Up to approximately 30 months

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment.

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=60 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) n=6 Participants Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Objective Response Rate (ORR) Per Lugano Classification as Assessed by Investigator	66.7 Percentage of Participants Interval 53.3 to 78.3	50.0 Percentage of Participants Interval 11.8 to 88.2

SECONDARY outcome

Timeframe: Up to approximately 30 months

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment.

ORR was defined as the percentage of the participants who had complete response (CR) or partial response (PR) and was evaluated using computed tomography (CT) and metabolic imaging (fluorodeoxyglucose-positron emission tomography (FDG-PET)). CR is complete metabolic (no/minimal FDG uptake) and radiologic response (target lesions regress to ≤1.5 cm in longest transverse diameter of a lesion) and no new lesions. PR is partial metabolic (moderate/high FDG uptake) and radiologic response (≥50% decrease in sum of product diameters for multiple lesions of up to 6 target measurable nodes and extranodal sites, no increase in lesions, and spleen regressed by \>50% in length beyond normal). The percentage of participants treated with pembrolizumab Q6W, by cohort, rrcHL and rrPMBCL, who experienced CR or PR as assessed by BICR is presented.

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=60 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) n=6 Participants Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
ORR Per Lugano Classification as Assessed by Blinded Independent Central Review (BICR)	70.0 Percentage of Participants Interval 56.8 to 81.2	66.7 Percentage of Participants Interval 22.3 to 95.7

SECONDARY outcome

Timeframe: Up to approximately 54 months

For participants who demonstrate a CR or PR, DOR is defined as the time from the first documented evidence of CR or PR until disease progression or death due to any cause, whichever occurs first. Participants will be evaluated using CT and metabolic imaging (FDG-PET). CR is complete metabolic (no/minimal FDG uptake) and radiologic response (target lesions regress to ≤1.5 cm in longest transverse diameter of a lesion) and no new lesions. PR is partial metabolic (moderate/high FDG uptake) and radiologic response (≥50% decrease in sum of product diameters for multiple lesions of up to 6 target measurable nodes and extranodal sites, no increase in lesions, and spleen regressed by \>50% in length beyond normal). DOR as assessed by investigator is presented among participants who demonstrated CR or PR.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to approximately 54 months

For participants who demonstrate a CR or PR, DOR is defined as the time from the first documented evidence of CR or PR until disease progression or death due to any cause, whichever occurs first. Participants will be evaluated using CT and metabolic imaging (FDG-PET). CR is complete metabolic (no/minimal FDG uptake) and radiologic response (target lesions regress to ≤1.5 cm in longest transverse diameter of a lesion) and no new lesions. PR is partial metabolic (moderate/high FDG uptake) and radiologic response (≥50% decrease in sum of product diameters for multiple lesions of up to 6 target measurable nodes and extranodal sites, no increase in lesions, and spleen regressed by \>50% in length beyond normal). DOR as assessed by BICR is presented among participants who demonstrated CR or PR.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Predose on Day 1 and Day 42 of Cycle 1 (cycle length=6 weeks)

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment. The analysis was pre-specified to be a pooled analysis of all participants rrcHL or rrPMBCL.

AUC was defined as a measure of pembrolizumab exposure that was calculated as the product of serum drug concentration and time. Blood samples were collected to determine the AUC of pembrolizumab during Cycle 1 (early cycle). A cycle was 6 weeks.

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=66 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Area Under the Curve (AUC) Early Cycle of Pembrolizumab	NA day*µg/mL AUC was determined by trapezoidal methods using interpolation between data points. Thus, at least 3 data points in the terminal phase excluding Tmax (i.e., end of infusion) were required to determine AUC. Due to sparse PK sampling schedule, per participant data could not be calculated.	—

SECONDARY outcome

Timeframe: Predose on Day 1 and Day 42 of Cycle 4 (cycle length=6 weeks)

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=66 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Area Under the Curve (AUC) Steady State of Pembrolizumab	NA day*µg/mL AUC was determined by trapezoidal methods using interpolation between data points. Thus, at least 3 data points in the terminal phase excluding Tmax (i.e., end of infusion) were required to determine AUC. Due to sparse PK sampling schedule, per participant data could not be calculated.	—

SECONDARY outcome

Timeframe: Predose on Day 1 of Cycle 1 and end of infusion on Day 1 of Cycle 1 (cycle length = 6 weeks)

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment and had Cycle 1 end of infusion concentration available. A cycle is 6 weeks. The analysis was pre-specified to be a pooled analysis of all participants rrcHL or rrPMBCL.

Cmax is defined as the maximum serum drug concentration. Blood samples were collected to determine the Cmax of pembrolizumab during Cycle 1 (early cycle).

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=61 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Maximum Serum Concentration (Cmax) Early Cycle of Pembrolizumab	127.5 μg/ml Interval 120.0 to 135.4	—

SECONDARY outcome

Timeframe: Predose on Day 1 of Cycle 4, and end of infusion on Day 1 of Cycle 4 (cycle length = 6 weeks)

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment and had Cycle 4 end of infusion concentration available. A cycle is 6 weeks. The analysis was pre-specified to be a pooled analysis of all participants rrcHL or rrPMBCL.

Cmax is defined as the maximum serum drug concentration. Blood samples were collected to determine the Cmax of pembrolizumab during Cycle 4 (steady state).

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=41 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Maximum Serum Concentration (Cmax) Steady State of Pembrolizumab	154.8 μg/ml Interval 141.5 to 169.4	—

SECONDARY outcome

Timeframe: Predose on Day 1 of Cycle 1 and Day 42 of Cycle 1 (cycle length = 6 weeks)

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment and had Cycle 1 trough concentration available. A cycle is 6 weeks. The analysis was pre-specified to be a pooled analysis of all participants with rrcHL or rrPMBCL.

Ctrough is defined as the lowest serum drug concentration. Blood samples were collected to determine the Ctrough of pembrolizumab during Cycle 1 (early cycle).

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=61 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Trough Serum Concentration (Ctrough) Early Cycle of Pembrolizumab	17.9 μg/ml Interval 16.3 to 19.7	—

SECONDARY outcome

Timeframe: Predose on Day 1 of Cycle 1 and Day 42 of Cycle 4 (cycle length = 6 weeks)

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment and had Cycle 4 trough concentration available. A cycle is 6 weeks. The analysis was pre-specified to be a pooled analysis of all participants with rrcHL or rrPMBCL.

Ctrough is defined as the lowest serum drug concentration. Blood samples were collected to determine the Ctrough of pembrolizumab during Cycle 4 (steady state).

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=44 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Trough Serum Concentration (Ctrough) Steady State of Pembrolizumab	33.8 μg/ml Interval 29.9 to 38.4	—

SECONDARY outcome

Timeframe: Predose 0-4 hours on Cycle1 Day1, Cycle2 Day1, Cycle4 Day1, Cycle5 Day1, Cycle7 Day1, Cycle9 Day1, Cycle13 Day1, Cycle17 Day1 and end of infusion on Cycle1 Day1, Cycle4 Day1 and anytime on Cycle1 Day22 and Cycle4 Day22 (cycle length = 6 weeks)

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment and had a negative ADA or positive ADA status. The analysis was pre-specified to be a pooled analysis of all participants with rrcHL or rrPMBCL.

Blood samples were collected and assayed for anti-pembrolizumab antibodies presence using a validated electrochemiluminescence immunoassay. Negative ADA refers to all pre-treatment and postdose samples negative in the assay for antibodies against pembrolizumab and the concentration of pembrolizumab in the last postdose sample below the drug tolerance level. Treatment emergent positive was defined as pre-treatment sample negative and at least one postdose sample positive in the assay or pre-treatment and postdose sample positive with an increase in titer (≥2 fold of baseline). Non-treatment emergent positive was defined as pre-treatment sample positive and postdose sample negative or pre-treatment and postdose sample positive with a postdose titer \<2 fold of baseline. Neutralizing positive was defined as at least 1 of the ADA positive samples test positive in the neutralizing assay.

Outcome measures

Outcome measures
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=64 Participants Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Antidrug Antibody Levels (ADA) for Pembrolizumab Negative	62 Participants	—
Antidrug Antibody Levels (ADA) for Pembrolizumab Treatment emergent positive	1 Participants	—
Antidrug Antibody Levels (ADA) for Pembrolizumab Non-Treatment emergent positive	1 Participants	—
Antidrug Antibody Levels (ADA) for Pembrolizumab Neutralizing positive	0 Participants	—

SECONDARY outcome

Timeframe: Up to approximately 54 months

An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Up to approximately 54 months

Outcome measures

Outcome data not reported

Adverse Events

Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL)

Serious events: 5 serious events

Other events: 38 other events

Deaths: 9 deaths

Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL)

Serious events: 0 serious events

Other events: 4 other events

Deaths: 3 deaths

Serious adverse events

Serious adverse events
Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=60 participants at risk Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) n=6 participants at risk Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Blood and lymphatic system disorders Febrile neutropenia	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Gastrointestinal disorders Gastric stenosis	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Peritonitis	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Pneumonia	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Urinary tract infection	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Metabolism and nutrition disorders Hypercalcaemia	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Psychiatric disorders Depression	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.

Other adverse events

Additional Information

Senior Vice President, Global Clinical Development

Merck Sharp & Dohme LLC

Phone: 1-800-672-6372

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee The investigator agrees to submit all manuscripts or abstracts to the Sponsor before submission. This allows the Sponsor to protect proprietary information and to provide comments.
Publication restrictions are in place

Restriction type: OTHER

Measure	Relapsed or Refractory Classical Hodgkin's Lymphoma (rrcHL) n=60 participants at risk Participants with rrcHL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.	Relapsed or Refractory Primary Mediastinal Large B-cell Lymphoma (rrPMBCL) n=6 participants at risk Participants with rrPMBCL received pembrolizumab 400 mg as an intravenous (IV) infusion on Day 1, then every six weeks (Q6W) up to 18 doses.
Blood and lymphatic system disorders Neutropenia	6.7% 4/60 • Number of events 5 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 3 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Cardiac disorders Atrial fibrillation	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Cardiac disorders Tachycardia	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Endocrine disorders Hypothyroidism	13.3% 8/60 • Number of events 8 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Gastrointestinal disorders Abdominal pain	8.3% 5/60 • Number of events 7 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Gastrointestinal disorders Diarrhoea	13.3% 8/60 • Number of events 8 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Gastrointestinal disorders Nausea	10.0% 6/60 • Number of events 6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
General disorders Fatigue	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
General disorders Peripheral swelling	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
General disorders Pyrexia	3.3% 2/60 • Number of events 3 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 3 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations COVID-19	21.7% 13/60 • Number of events 13 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Device related bacteraemia	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Rhinitis	6.7% 4/60 • Number of events 7 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Upper respiratory tract infection	21.7% 13/60 • Number of events 18 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Infections and infestations Urinary tract infection	8.3% 5/60 • Number of events 6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Investigations Blood thyroid stimulating hormone decreased	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Investigations Weight increased	8.3% 5/60 • Number of events 5 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Musculoskeletal and connective tissue disorders Arthralgia	6.7% 4/60 • Number of events 4 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Musculoskeletal and connective tissue disorders Bone pain	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Musculoskeletal and connective tissue disorders Musculoskeletal pain	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Nervous system disorders Headache	6.7% 4/60 • Number of events 8 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Respiratory, thoracic and mediastinal disorders Cough	3.3% 2/60 • Number of events 2 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Skin and subcutaneous tissue disorders Anhidrosis	0.00% 0/60 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Skin and subcutaneous tissue disorders Dry skin	1.7% 1/60 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	16.7% 1/6 • Number of events 1 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.
Skin and subcutaneous tissue disorders Pruritus	8.3% 5/60 • Number of events 5 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.	0.00% 0/6 • Up to approximately 30 months The analysis population for AEs included all participants who received ≥1 dose of study treatment. MedDRA preferred terms "neoplasm progression (NP)", "malignant NP" and "disease progression" not related to study treatment are excluded.