Trial Outcomes & Findings for Pembrolizumab (MK-3475) as First-line Therapy for Advanced Merkel Cell Carcinoma (MK-3475-913) (NCT NCT03783078)

NCT ID: NCT03783078

Last Updated: 2025-05-28

Results Overview

ORR was defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). The percentage of participants who experienced CR or PR as assessed by blinded independent central review (BICR) were presented.

• Recruitment status: COMPLETED
• Study phase: PHASE3
• Target enrollment: 55 participants
• Primary outcome timeframe: Up to ~34 months
• Results posted on: 2025-05-28

Participant Flow

Participants of at least 12 years of age with advanced Merkel cell carcinoma (MCC) were recruited to evaluate the safety and efficacy of Pembrolizumab (MK-3475) as first-line therapy.

Participant milestones

Measure	Pembrolizumab 200 mg Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 of each 3-week cycle (Q3W) intravenously (IV), for up to 35 administrations (approximately 2 years).
Overall Study STARTED	55
Overall Study COMPLETED	0
Overall Study NOT COMPLETED	55

Reasons for withdrawal

Measure	Pembrolizumab 200 mg Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 of each 3-week cycle (Q3W) intravenously (IV), for up to 35 administrations (approximately 2 years).
Overall Study Death	31
Overall Study Sponsor Decision	23
Overall Study Withdrawal by Parent/Guardian	1

Baseline Characteristics

Pembrolizumab (MK-3475) as First-line Therapy for Advanced Merkel Cell Carcinoma (MK-3475-913)

Baseline characteristics by cohort

Measure	Pembrolizumab 200 mg n=55 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Age, Continuous	72.5 Years STANDARD_DEVIATION 11.7 • n=5 Participants
Sex: Female, Male Female	24 Participants n=5 Participants
Sex: Female, Male Male	31 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	35 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	20 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants
Race (NIH/OMB) Asian	0 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants
Race (NIH/OMB) White	39 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	16 Participants n=5 Participants

PRIMARY outcome

Timeframe: Up to ~34 months

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

ORR was defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). The percentage of participants who experienced CR or PR as assessed by blinded independent central review (BICR) were presented.

Outcome measures

Measure	Pembrolizumab 200 mg n=55 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Objective Response Rate (ORR)	49.1 Percentage of participants Interval 35.4 to 62.9

SECONDARY outcome

Timeframe: Up to ~58 months

Population: The analysis population consisted of all allocated participants who received at least 1 dose of study treatment, and who experienced a confirmed CR or confirmed PR.

For participants who demonstrated a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: At least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1, DOR was defined as the time from first documented evidence of a CR or PR until progressive disease (PD) or death. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. Per RECIST 1.1, PD was defined as at least a 20% increase in the sum of diameters of target lesions as well as an absolute increase of at least a 5 mm in the sum of diameters. The appearance of one or more new lesions was also considered PD. DOR assessments were based on BICR with confirmation. The DOR as assessed using RECIST 1.1 for all participants who experienced a confirmed CR or PR was presented.

Outcome measures

Measure	Pembrolizumab 200 mg n=27 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Duration of Response (DOR)	39.8 Months Interval 23.8 to NA = Upper limit not reached at time of data cut-off due to insufficient number of responding participants with relapse.

SECONDARY outcome

Timeframe: Up to ~58 months

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

Progression-Free Survival was defined as the time from the first dose of study treatment to the first documented evidence of disease progression per RECIST 1.1 by BICR or death due to any cause, whichever occurred first. Per RECIST 1.1, PD was defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also have demonstrated an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. PFS as assessed by BICR per RECIST 1.1 was presented.

Outcome measures

Measure	Pembrolizumab 200 mg n=55 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Progression-free Survival (PFS)	9.3 Months Interval 3.0 to 25.5

SECONDARY outcome

Timeframe: Up to ~58 months

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

OS was defined as the time from the first dose of study treatment until death from any cause.

Outcome measures

Measure	Pembrolizumab 200 mg n=55 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Overall Survival (OS)	24.3 Months Interval 12.4 to NA = Upper limit not reached at time of data cut-off due to insufficient number of participants with an event

SECONDARY outcome

Timeframe: Up to ~58 months

Population: The analysis population consisted of all allocated participants who received at least one dose of study treatment.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants with at least one AE was assessed.

Outcome measures

Measure	Pembrolizumab 200 mg n=55 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Number of Participants With One or More Adverse Events (AEs)	52 Participants

SECONDARY outcome

Timeframe: Up to ~27 months

Population: The analysis population consisted of all allocated participants who received at least one dose of study treatment.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants who discontinued from study treatment due to an AE was assessed.

Outcome measures

Measure	Pembrolizumab 200 mg n=55 Participants Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Number of Participants Who Discontinued From Study Treatment Due to an AE	18 Participants

Adverse Events

Pembrolizumab 200 mg

Serious events: 24 serious events

Other events: 49 other events

Deaths: 32 deaths

Serious adverse events

Measure	Pembrolizumab 200 mg n=55 participants at risk Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Gastrointestinal disorders Colitis	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Dysphagia	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Obstructive pancreatitis	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Small intestinal obstruction	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Subileus	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
General disorders Fatigue	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Cellulitis	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Cystitis	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Empyema	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Encephalitis	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Erysipelas	1.8% 1/55 • Number of events 2 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Pneumonia	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Respiratory syncytial virus infection	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Upper respiratory tract infection	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Wound infection	1.8% 1/55 • Number of events 2 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Musculoskeletal and connective tissue disorders Muscular weakness	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Basal cell carcinoma	3.6% 2/55 • Number of events 11 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Squamous cell carcinoma	1.8% 1/55 • Number of events 9 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Squamous cell carcinoma of skin	1.8% 1/55 • Number of events 2 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Transitional cell carcinoma	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Cerebral haemorrhage	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Cerebrovascular accident	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Chronic inflammatory demyelinating polyradiculoneuropathy	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Guillain-Barre syndrome	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Loss of consciousness	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Parkinson's disease	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Renal and urinary disorders Acute kidney injury	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Renal and urinary disorders Hydronephrosis	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Respiratory, thoracic and mediastinal disorders Dyspnoea exertional	1.8% 1/55 • Number of events 1 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Respiratory, thoracic and mediastinal disorders Pulmonary embolism	3.6% 2/55 • Number of events 2 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.

Other adverse events

Measure	Pembrolizumab 200 mg n=55 participants at risk Adult participants received pembrolizumab (MK-3475) 200 mg or pediatric participants received 2 mg/kg (up to 200 mg) on Day 1 Q3W IV for up to 35 administrations (approximately 2 years).
Blood and lymphatic system disorders Anaemia	16.4% 9/55 • Number of events 11 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Ear and labyrinth disorders Vertigo	5.5% 3/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Endocrine disorders Hyperthyroidism	5.5% 3/55 • Number of events 3 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Endocrine disorders Hypothyroidism	5.5% 3/55 • Number of events 3 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Abdominal pain	9.1% 5/55 • Number of events 6 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Constipation	16.4% 9/55 • Number of events 9 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Diarrhoea	12.7% 7/55 • Number of events 11 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Dry mouth	9.1% 5/55 • Number of events 5 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Nausea	14.5% 8/55 • Number of events 10 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Gastrointestinal disorders Vomiting	9.1% 5/55 • Number of events 5 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
General disorders Asthenia	20.0% 11/55 • Number of events 20 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
General disorders Fatigue	25.5% 14/55 • Number of events 18 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
General disorders Oedema peripheral	9.1% 5/55 • Number of events 5 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
General disorders Pyrexia	12.7% 7/55 • Number of events 9 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations COVID-19	7.3% 4/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Infections and infestations Urinary tract infection	5.5% 3/55 • Number of events 6 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Injury, poisoning and procedural complications Fall	5.5% 3/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Alanine aminotransferase increased	18.2% 10/55 • Number of events 13 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Amylase increased	9.1% 5/55 • Number of events 6 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Aspartate aminotransferase increased	21.8% 12/55 • Number of events 14 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Blood alkaline phosphatase increased	7.3% 4/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Blood creatine phosphokinase increased	5.5% 3/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Blood creatinine increased	7.3% 4/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Lipase increased	18.2% 10/55 • Number of events 11 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Investigations Weight decreased	12.7% 7/55 • Number of events 7 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Metabolism and nutrition disorders Decreased appetite	10.9% 6/55 • Number of events 7 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Metabolism and nutrition disorders Hypokalaemia	5.5% 3/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Musculoskeletal and connective tissue disorders Arthralgia	18.2% 10/55 • Number of events 12 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Musculoskeletal and connective tissue disorders Back pain	16.4% 9/55 • Number of events 11 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Musculoskeletal and connective tissue disorders Myalgia	7.3% 4/55 • Number of events 11 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Musculoskeletal and connective tissue disorders Osteoarthritis	7.3% 4/55 • Number of events 5 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Musculoskeletal and connective tissue disorders Pain in extremity	9.1% 5/55 • Number of events 5 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Dysgeusia	7.3% 4/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Nervous system disorders Headache	10.9% 6/55 • Number of events 7 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Psychiatric disorders Insomnia	5.5% 3/55 • Number of events 3 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Renal and urinary disorders Dysuria	5.5% 3/55 • Number of events 3 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Renal and urinary disorders Haematuria	7.3% 4/55 • Number of events 5 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Respiratory, thoracic and mediastinal disorders Dyspnoea	10.9% 6/55 • Number of events 6 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Skin and subcutaneous tissue disorders Actinic keratosis	5.5% 3/55 • Number of events 3 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Skin and subcutaneous tissue disorders Alopecia	7.3% 4/55 • Number of events 4 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Skin and subcutaneous tissue disorders Eczema	9.1% 5/55 • Number of events 6 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Skin and subcutaneous tissue disorders Erythema	5.5% 3/55 • Number of events 3 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Skin and subcutaneous tissue disorders Pruritus	23.6% 13/55 • Number of events 19 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.
Skin and subcutaneous tissue disorders Rash	9.1% 5/55 • Number of events 6 • Up to ~58 months All-cause mortality includes all allocated participants. AEs include participants who received ≥1 dose of study treatment. Per protocol, disease progression was not considered an AE, unless related to study treatment. Thus, MedDRA preferred terms "Neoplasm progression", "Malignant neoplasm progression" and "Disease progression" not related to study treatment were excluded as AEs.

Additional Information

Senior Vice President, Global Clinical Development

Merck Sharp & Dohme LLC

Phone: 1-800-672-6372

Email: ClinicalTrialsDisclosure@msd.com

Results disclosure agreements

• Principal investigator is a sponsor employee If publication activity is not directed by the Sponsor, 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