NCT07302347

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)

A Phase I/II Study of Pembrolizumab (MK-3475) in Japanese Pediatric Participants With Specific Solid Tumors or Lymphomas, or in Japanese Adult Participants With Advanced Merkel Cell Carcinoma (KEYNOTE-G21)

• Status: Recruiting
• Phase: Phase 1 / Phase 2
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: Merck Sharp & Dohme LLC · Industry
• Sex: All
• Age: 6 Months
• Healthy volunteers: Not accepted

Summary

Researchers are looking for new ways to treat people with solid tumors, lymphomas (blood cancers), and a certain type of skin cancer. The goals of this study are to learn: * About the safety of pembrolizumab (the study medicine) and if people tolerate it * What happens to different doses of pembrolizumab in a person's body over time * How the cancer responds (gets smaller or goes away) to treatment

Conditions

• Malignant Neoplasm
• Carcinoma, Merkel Cell
• Lymphoma

Interventions

Type	Name	Description
BIOLOGICAL	Pembrolizumab	25 mg/mL solution for intravenous infusion.

Timeline

• Start date: 2026-06-30
• Primary completion: 2029-03-30
• Completion: 2029-12-31
• First posted: 2025-12-24
• Last updated: 2026-04-17

Locations

2 sites across 1 country: Japan