September 21, 2026 6:45 am EDT--RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the Ministry of Health, Labor and Welfare (MHLW) in Japan has approved KEYTRUDA QLEX™ (pembrolizumab and berahyaluronidase alfa-pmph) injection for subcutaneous use for all indications approved in Japan for KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy. In Japan, KEYJECT®, for subcutaneous injection is the planned trademark for KEYTRUDA QLEX. KEYJECT can be administered in one minute every three weeks or in two minutes every six weeks. Berahyaluronidase alfa is a variant of hyaluronidase developed and manufactured by Alteogen Inc. For a list of select indications for which KEYTRUDA and KEYTRUDA QLEX are approved in the United States, see Selected Indications in the U.S. below.
“KEYJECT is the first and only subcutaneous immune checkpoint inhibitor available in Japan that can be administered by a healthcare provider in as little as one minute,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “This approval is a significant milestone for patients and healthcare providers in Japan and reflects our commitment to advancing new patient-centered care options like KEYJECT that offers patients two dosing options and more choices of health care settings where they can receive therapy.”
The approval of KEYJECT is based on results from the pivotal Phase 3 MK-3475A-D77 trial which compared KEYJECT to KEYTRUDA, both administered every six weeks, each in combination with chemotherapy, in patients with treatment-naïve metastatic non-small cell lung cancer (NSCLC) with no EGFR, ALK or ROS1 genomic tumor aberrations. This trial demonstrated comparable pharmacokinetic exposure levels between KEYJECT and KEYTRUDA. In descriptive analyses, overall response rates (ORR) were consistent between KEYJECT and KEYTRUDA. The ORR in the KEYJECT with chemotherapy arm was 45% (95% CI, 39-52) and 42% (95% CI, 33-51) in the KEYTRUDA with chemotherapy arm. There were no notable differences in progression-free survival (PFS) and overall survival (OS) observed in patients who received KEYJECT compared to patients who received KEYTRUDA.
In September 2025, the U.S. Food and Drug Administration (FDA) approved KEYTRUDA QLEX and it is now approved for adults in all the same solid tumor indications as KEYTRUDA. The European Commission approved subcutaneous pembrolizumab [known as KEYTRUDA SC™ in the European Union (EU)] in November 2025, and it is now approved for all KEYTRUDA indications in Europe.
About Study MK-3475A-D77
Study 3475A-D77 is a multicenter, randomized, open-label, active-controlled Phase 3 trial (ClinicalTrials.gov, NCT05722015) conducted in patients with treatment-naïve metastatic non-small cell lung cancer (NSCLC) with no EGFR, ALK or ROS1 genomic tumor aberrations. The primary outcome measure was pembrolizumab exposure [Cycle 1 AUC0-6 weeks and Cycle 3 (i.e. Steady State) Ctrough] of KEYJECT as compared to KEYTRUDA. Additional descriptive efficacy outcome measures were ORR by blinded independent central review (BICR), PFS by BICR and OS. A total of 377 patients were randomized 2:1 to receive either KEYJECT (790 mg/9,600 units) every six weeks with platinum doublet chemotherapy (n=251) or KEYTRUDA (400 mg) every six weeks with platinum doublet chemotherapy (n=126).
About subcutaneous administration
Subcutaneous administration is a method of delivering medications under the skin. Subcutaneous administration may provide added convenience because it offers more options where patients can receive their treatment because it can be administered by healthcare providers in multiple settings from an infusion center to a doctor’s office or a local community-based clinic. For patients who do not require a port or whose veins are difficult to access, subcutaneous administration may simplify treatment administration.
About KEYTRUDA® (pembrolizumab) injection for intravenous use, 100 mg
KEYTRUDA is an anti-programmed death receptor-1 (PD-1) therapy that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. KEYTRUDA is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.
Merck has the industry’s largest immuno-oncology clinical research program. There are currently more than 2,800 trials studying KEYTRUDA across a wide variety of cancers and treatment settings. The KEYTRUDA clinical program seeks to understand the role of KEYTRUDA across cancers and the factors that may predict a patient's likelihood of benefitting from treatment with KEYTRUDA, including exploring several different biomarkers.
About KEYTRUDA QLEX™ (pembrolizumab and berahyaluronidase alfa-pmph) injection for subcutaneous use, 165 mg + 2,000 units/mL
KEYTRUDA QLEX is a fixed-combination drug product of pembrolizumab and berahyaluronidase alfa. Pembrolizumab is a programmed death receptor-1 (PD-1) blocking antibody and berahyaluronidase alfa enhances dispersion and permeability to enable subcutaneous administration of pembrolizumab. KEYTRUDA QLEX is administered as a subcutaneous injection into the thigh or abdomen, avoiding the 5 cm area around the navel, over one minute every three weeks (2.4 mL) or over two minutes every six weeks (4.8 mL).
Merck’s focus on cancer
Every day, we follow the science as we work to discover innovations that can help patients, no matter what stage of cancer they have. As a leading oncology company, we are pursuing research where scientific opportunity and medical need converge, underpinned by our diverse pipeline of more than 20 novel mechanisms. With one of the largest clinical development programs across more than 25 tumor types, we strive to advance breakthrough science that will shape the future of oncology. By addressing barriers to clinical trial participation, screening and treatment, we work with urgency to reduce disparities and help ensure patients have access to high-quality cancer care. Our unwavering commitment is what will bring us closer to our goal of bringing life to more patients with cancer.
About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities.