This marks the approval of the first and only subcutaneous immune checkpoint inhibitor in Europe that can be administered by a health care provider in as little as one minute
November 19, 2025--RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced that the European Commission (EC) has approved a new subcutaneous (SC), or under the skin, route of administration and a new pharmaceutical form (solution for injection) of KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy. KEYTRUDA SC™, as it will be marketed in the European Union (EU), [known as KEYTRUDA QLEXTM (pembrolizumab and berahyaluronidase alfa-pmph) in the U.S.], is a subcutaneous injection containing pembrolizumab and berahyaluronidase alfa and has been approved for use across all 33 KEYTRUDA indications for adult patients in Europe. Berahyaluronidase alfa is a variant of human 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.
“We are honored to introduce KEYTRUDA SC, the first and only subcutaneous immune checkpoint inhibitor in Europe that can be administered in one minute every three weeks or in two minutes every six weeks,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “We are committed to discovering patient-focused innovations for people with cancer like KEYTRUDA SC, which offers faster administration than KEYTRUDA, two dosing options and allows patients more choices of health care settings where they can receive therapy.”
The approval of KEYTRUDA SC is based on results from the pivotal 3475A-D77 trial, which compared KEYTRUDA SC and 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 KEYTRUDA SC and KEYTRUDA. In descriptive efficacy analyses, overall response rates (ORR) were consistent between KEYTRUDA SC and KEYTRUDA. The ORR in the KEYTRUDA SC with chemotherapy arm was 45% (95% CI, 39-52) and 42% (95% CI, 33-51) in the KEYTRUDA with chemotherapy arm. Additionally, no notable differences were observed in progression-free survival (PFS) and overall survival (OS).
This decision authorizes the marketing of KEYTRUDA SC in all 27 EU member states, as well as Iceland, Liechtenstein and Norway. Timing for commercial availability of KEYTRUDA SC in individual EU countries will depend on multiple factors, including the completion of national reimbursement procedures.
The EC approval follows the positive recommendation from the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) received in September 2025. Also in September 2025, KEYTRUDA QLEX was approved by the U.S. Food and Drug Administration (FDA). In the United States, KEYTRUDA QLEX is now approved for use in adults across all solid tumor indications approved for KEYTRUDA.
About subcutaneous administration
Subcutaneous administration is a method of delivering medications under the skin, offering faster administration than intravenous infusion. Subcutaneous administration may provide added convenience because it offers more options where patients can receive their treatment because it can be administered by health care 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 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 KEYTRUDA SC 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 KEYTRUDA SC (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).
At the primary analysis, the confirmed ORR was 45% (95% Cl, 39-52) in the KEYTRUDA SC arm versus 42% (95% Cl, 33-51) for the KEYTRUDA arm. There were no notable differences in PFS and OS observed in patients who received KEYTRUDA SC compared to patients who received KEYTRUDA.
The most common adverse reactions (≥20%) of patients who received KEYTRUDA SC in combination with chemotherapy were nausea (25%), fatigue (25%), and musculoskeletal pain (21%).
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 1,600 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).
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.