Merck’s KEYTRUDA QLEX has been approved in Japan for subcutaneous use across all indications currently approved for KEYTRUDA, giving patients another way to receive the cancer treatment.
Japan’s Ministry of Health, Labor and Welfare (MHLW) approved KEYTRUDA QLEX, a combination of pembrolizumab and berahyaluronidase alfa-pmph. In Japan, the treatment is planned to be marketed under the name KEYJECT.
Unlike standard intravenous KEYTRUDA, KEYTRUDA QLEX is given as an injection under the skin. Healthcare providers can administer it in about one minute every three weeks or two minutes every six weeks, according to Merck. The treatment is injected into the thigh or abdomen.
The approval is based on results from the Phase 3 MK-3475A-D77 trial, which compared KEYTRUDA QLEX with intravenous KEYTRUDA in patients with previously untreated metastatic non-small cell lung cancer (NSCLC). Patients in the study received either treatment every six weeks, along with chemotherapy.
The study found that the two treatments produced comparable levels of pembrolizumab exposure in the body. Response rates were also similar. The overall response rate was 45% among patients receiving KEYTRUDA QLEX with chemotherapy, compared with 42% for those receiving KEYTRUDA with chemotherapy. Merck reported no notable differences in progression-free survival or overall survival between the two treatment groups.
KEYTRUDA QLEX combines pembrolizumab, an immune checkpoint inhibitor that targets PD-1, with berahyaluronidase alfa. The second component helps improve the movement and absorption of pembrolizumab when it is given under the skin. Berahyaluronidase alfa was developed and is manufactured by Alteogen.
Merck said the Japanese approval could provide patients and healthcare providers with more flexibility in how and where treatment is delivered. The company described KEYTRUDA QLEX as the first subcutaneous immune checkpoint inhibitor available in Japan that can be administered by a healthcare provider in as little as one minute.
The approval also expands the global availability of subcutaneous pembrolizumab. The U.S. Food and Drug Administration approved KEYTRUDA QLEX in September 2025 for adults across most solid tumor indications covered by KEYTRUDA. The European Commission approved the subcutaneous formulation, known as KEYTRUDA SC in Europe, in November 2025.
For Merck, the Japanese decision further expands options for administering KEYTRUDA, one of the company’s key oncology medicines, while the company continues to study pembrolizumab across a wide range of cancers.