Merck's KEYNOTE-522 posts results in triple negative breast cancer; new PAH study starts in India

A busy week for Merck-linked trials included new Phase 3 results and a newly recruiting Phase 4 study.

• The Phase 3 "KEYNOTE-522" trial testing pembrolizumab plus chemotherapy against placebo plus chemotherapy, given before surgery and continued after, in triple negative breast cancer has posted results. The study tested whether adding pembrolizumab to chemotherapy would outperform chemotherapy alone, measured by pathological complete response rates and event-free survival, in people with locally advanced disease.¹ The enrollment reached 1,174 participants, who received 200 mg of pembrolizumab or placebo every three weeks alongside paclitaxel, carboplatin, and either doxorubicin or epirubicin plus cyclophosphamide.¹
• A Phase 4, single-arm study of sotatercept in adults with pulmonary arterial hypertension in India is recruiting, sponsored by Merck Sharp & Dohme LLC. The goal of the study is to assess the safety and tolerability of sotatercept given alongside standard PAH treatment in patients in India.² The trial plans to enroll 30 participants, who receive sotatercept subcutaneously every 21 days starting at 0.3 mg/kg with a target dose of 0.7 mg/kg, on top of background PAH therapy.²
• A Phase 2 study of lenvatinib, pembrolizumab, and weekly paclitaxel in recurrent endometrial, ovarian, fallopian tube and primary peritoneal cancer, led by Ohio State's Floor Backes with Merck Sharp & Dohme LLC as a collaborator, has posted results. The trial enrolled 38 participants across several platinum-resistant and recurrent cancer types, with objective tumor response by RECIST as the primary outcome.³
• Merck's Phase 1 study of enlicitide decanoate (MK-0616) in participants with severe renal impairment is completed, with pharmacokinetic data posted. Enlicitide decanoate is designed to lower low-density lipoprotein cholesterol in the blood.⁴ The posted results showed an AUC0-24 of 347 hr*nmol/L in participants with severe renal impairment compared with 236 hr*nmol/L in healthy participants.
• A University of Hawaii-sponsored study of metformin in HIV-infected individuals on antiretroviral therapy, with Merck Sharp & Dohme LLC as a collaborator, was terminated. Enrollment was halted during the COVID pandemic by the study's institutional review board, and the sponsor later decided to end the trial.⁵ The posted primary outcome showed a change in CD4 T cells co-expressing PD-1 and TIGIT of -0.787 with metformin versus -1.466 with observation (p=0.8125).