Subcutaneous pembrolizumab administered every six weeks with a median injection time of two minutes, in combination with chemotherapy, shows consistent results across reported efficacy and safety endpoints compared to IV KEYTRUDA in combination with chemotherapy

A time and motion descriptive analysis shows nearly 50% reductions in patient chair and treatment room time, and in total active healthcare professional time related to treatment tasks, for subcutaneous pembrolizumab compared to IV KEYTRUDA

Applications for subcutaneous pembrolizumab are under review in the U.S. and Europe

Merck (NYSE:MRK), known as MSD outside of the United States and Canada, today announced the first data presentation from the pivotal 3475A-D77 Phase 3 trial, evaluating the subcutaneous administration of pembrolizumab, together with berahyaluronidase alfa (MK-3475A; from now on referred to as "subcutaneous pembrolizumab"). Berahyaluronidase alfa is a variant of human hyaluronidase developed and manufactured by Alteogen Inc. These results are being presented today at the European Lung Cancer Congress (ELCC) 2025 (Abstract #8MO) and published simultaneously in Annals of Oncology.

The study met its primary endpoints, demonstrating noninferior pharmacokinetics (PK) for subcutaneous pembrolizumab administered with chemotherapy with a median injection time of two minutes, versus intravenous (IV) KEYTRUDA® (pembrolizumab) administered with chemotherapy for the first-line treatment of adult patients with metastatic non-small cell lung cancer (NSCLC). The secondary endpoints of objective response rate (ORR), progression-free survival (PFS) and duration of response (DOR) and safety were consistent for subcutaneous pembrolizumab with chemotherapy compared to IV KEYTRUDA with chemotherapy. Median overall survival (OS) was not reached in either arm.

Based on these data, the U.S. Food and Drug Administration (FDA) has accepted for review a Biologics License Application (BLA) seeking approval of subcutaneous pembrolizumab across all previously approved solid tumor indications for KEYTRUDA. The FDA has set a Prescription Drug User Fee Act (PDUFA), or target action, date of Sept. 23, 2025. Additionally, the European Medicines Agency (EMA) has validated an extension application to introduce a new pharmaceutical form and new route of administration for KEYTRUDA.

In addition, results of a prospective, observational time and motion descriptive analysis conducted alongside study 3475A-D77 show that, compared to IV KEYTRUDA, subcutaneous pembrolizumab reduced time for patients spent in-chair and in the treatment room by 49.7% and 47.4%, respectively, and reduced the total active time spent by healthcare professionals (HCPs) on treatment preparation, administration process and patient monitoring by 45.7%. These results are being presented as a poster at ELCC (Poster #33P). Pharmacokinetic, efficacy, safety and time and motion results are described further below.