Actively Recruiting
A Phase I/II Study of Pembrolizumab in Japanese Pediatric Participants With Solid Tumors or Lymphomas and Japanese Adults With Advanced Merkel Cell Carcinoma
Led by Merck Sharp & Dohme LLC · Updated on 2026-06-05
20
Participants Needed
6
Research Sites
39 weeks
Total Duration
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AI-Summary
What this Trial Is About
Researchers are evaluating pembrolizumab, a study medicine, in Japanese pediatric participants with specific solid tumors or lymphomas and Japanese adult participants with Merkel cell carcinoma (MCC), a type of skin cancer. The study aims to understand the safety and tolerability of pembrolizumab, how different doses behave in the body over time, and how the cancer responds to the treatment. This research is conducted as a Phase I/II trial sponsored by Merck Sharp & Dohme LLC. Pediatric participants with solid tumors or lymphomas receive pembrolizumab at a dose of 2 mg/kg through an intravenous infusion every three weeks on Day 1 of each 21-day cycle, for up to 17 or 35 cycles. Adult participants with MCC receive 400 mg pembrolizumab via intravenous infusion every six weeks (42-day cycle) for up to 18 cycles. Each study arm follows its own dosing schedule and treatment duration. Participants will be closely monitored through various assessments including measuring adverse events, drug concentrations in the blood at specified cycles, and cancer response evaluations using established criteria such as RECIST 1.1 and Lugano classification. The study tracks multiple outcomes like objective response rates, duration of response, disease control, progression-free survival, and overall survival, with follow-up periods extending up to approximately 46 months. Safety and treatment tolerability are key aspects monitored throughout the study duration.
CONDITIONS
Brief Title
A Study of Pembrolizumab in Japanese Pediatric Participants With Solid Tumors or Lymphomas and Japanese Adult Participants With Merkel Cell Carcinoma (MK-3475-G21/KEYNOTE-G21)
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Participants aged 6 months or older
- For pediatric participants: diagnosis of relapsed or refractory classical Hodgkin lymphoma or primary mediastinal large B-cell lymphoma with measurable disease
- For participants with completely resected melanoma: surgically removed stage IIB, IIC, III or IV cutaneous melanoma with no prior systemic therapy beyond surgery
- For participants with locally advanced or metastatic melanoma: unresectable or metastatic melanoma with measurable lesions
- For participants with MSI-H/dMMR or TMB-H solid tumors: incurable locally advanced or metastatic solid malignancy with measurable disease and specific test results
- For participants with Merkel cell carcinoma: locoregional MCC that recurred or metastatic MCC with measurable disease
- Life expectancy greater than 3 months (pediatric) or greater than 6 months (adult)
You will not qualify if you...
- Having another active malignancy requiring treatment or progressing
- Known active central nervous system metastases or carcinomatous meningitis
- Active autoimmune disease needing systemic treatment in the past 2 years
- History or current pneumonitis/interstitial lung disease requiring steroids
- Active infection requiring systemic therapy
- Known history of HIV infection
- Known history of Hepatitis B or active Hepatitis C infection
- Having had a solid organ transplant at any time or allogeneic stem cell transplant within past 5 years
- Not fully recovered from major surgery or having ongoing surgical complications
AI-Screening
AI-Powered Screening
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Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
screening and enrollment visit
Duration - Up to approximately 17 or 35 cycles for pediatric participants; up to 18 cycles for adult participants
Participants receive pembrolizumab via intravenous infusion on a repeating cycle schedule. Pediatric participants receive 2 mg/kg every 3 weeks for up to 17 or 35 cycles. Adult participants receive 400 mg every 6 weeks for up to 18 cycles.
Infusions every 3 weeks for pediatric participants or every 6 weeks for adult participants
Trial Site Locations
Total: 6 locations
1
Nagoya City University Hospital ( Site 0003)
Nagoya, Aichi-ken, Japan, 467-8602
Actively Recruiting
2
Nagoya City University Hospital ( Site 0007)
Nagoya, Aichi-ken, Japan, 467-8602
Actively Recruiting
3
Sapporo Hokuyu Hospital ( Site 0005)
Sapporo, Hokkaido, Japan, 003-0006
Actively Recruiting
4
Hyogo Prefectural Kobe Children's Hospital ( Site 0006)
Kobe, Hyōgo, Japan, 650-0047
Actively Recruiting
5
National Cancer Center Hospital ( Site 0002)
Chūō, Tokyo, Japan, 104-0045
Actively Recruiting
6
National Hospital Organization Kyushu Cancer Center ( Site 0001)
Fukuoka, Japan, 811-1395
Actively Recruiting
Research Team
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How is the study designed?
Study Type
INTERVENTIONAL
Masking
SINGLE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
2
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