Japan approves Merck's subcutaneous Keytruda injection

Merck announced on September 21, 2026, that Japan's Ministry of Health, Labor and Welfare approved Keytruda Qlex for subcutaneous injection. The clearance covers all indications approved in Japan for the intravenous formulation of Keytruda.

In Japan, the therapy will be marketed under the brand name Keyject. The fixed-combination drug pairs pembrolizumab with berahyaluronidase alfa, an enzyme developed by Alteogen Inc. It can be administered by a healthcare provider in one minute every three weeks or in two minutes every six weeks.

The approval relied on data from the Phase 3 MK-3475A-D77 trial evaluating 377 patients with treatment-naive metastatic non-small cell lung cancer. Keyject demonstrated comparable pharmacokinetic exposure to intravenous Keytruda. In descriptive analyses, the overall response rate reached 45% in the Keyject arm compared with 42% for intravenous Keytruda.

The Japanese decision follows previous regulatory clearances for subcutaneous pembrolizumab. The US Food and Drug Administration approved Keytruda Qlex in September 2025, and the European Commission authorized the subcutaneous formulation in November 2025.