Merck known as MSD outside of the United States and Canada, announced that the Phase 3 KEYNOTE-B96 trial, also known as ENGOT-ov65, met its primary endpoint of progression-free survival (PFS) for the treatment of patients with platinum-resistant recurrent ovarian cancer whose tumors expressed PD-L1 and in all comers.
The study also met a secondary endpoint of overall survival (OS) in patients whose tumors express PD-L1. The study is evaluating KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, in combination with chemotherapy (paclitaxel) with or without bevacizumab for these patients. The trial is continuing and OS for the full study population will be evaluated at a future analysis.
At pre-specified interim analyses conducted by an independent Data Monitoring Committee, the KEYTRUDA-based regimen demonstrated a statistically significant and clinically meaningful improvement in PFS regardless of PD-L1 status compared to placebo plus chemotherapy with or without bevacizumab. The study also showed a statistically significant and clinically meaningful improvement in OS in patients whose tumors express PD-L1 (Combined Positive Score [CPS] ≥1) compared to placebo plus chemotherapy with or without bevacizumab. The safety profile of KEYTRUDA in this trial was consistent with that observed in previously reported studies; no new safety signals were identified. Results will be presented at an upcoming medical meeting and shared with regulatory authorities worldwide.
“This marks the first time a KEYTRUDA-based regimen has shown the ability to help certain patients with platinum-resistant ovarian cancer live longer, and the first time an immune checkpoint inhibitor-based regimen has demonstrated an overall survival benefit in ovarian cancer,” said Dr. Gursel Aktan, vice president, global clinical development, Merck Research Laboratories. “The positive results from this trial add to the growing body of evidence supporting the potential benefit of KEYTRUDA across gynecological cancers, including this difficult-to-treat form of ovarian cancer for which patients are in need of new options.”
KEYTRUDA is not approved to treat ovarian cancer (see selected KEYTRUDA indications in the U.S. below). LYNPARZA® (olaparib), which is being jointly developed and commercialized by AstraZeneca and Merck, has three approved ovarian cancer indications in the U.S.: in first-line maintenance treatment of BRCA-mutated advanced ovarian cancer, following complete or partial response to first-line platinum-based chemotherapy; in first-line maintenance treatment of HRD-positive advanced ovarian cancer in combination with bevacizumab, following complete or partial response to first-line platinum-based chemotherapy; and in maintenance treatment of BRCA-mutated recurrent ovarian cancer, following complete or partial response to platinum-based chemotherapy. For each of these indications, patients are selected for therapy based on an FDA-approved companion diagnostic for LYNPARZA (see indications for LYNPARZA below). In 2024, Merck announced the initiation of the Phase 2/3 REJOICE-Ovarian01 trial evaluating raludotatug deruxtecan (R-DXd), an investigational potential first-in-class CDH6 directed DXd antibody-drug conjugate discovered by Daiichi Sankyo and being jointly developed with Merck, in patients with platinum-resistant ovarian cancer.
About KEYNOTE-B96/ENGOT-ov65:
KEYNOTE-B96, also known as ENGOT-ov65, is a randomized, double-blind Phase 3 trial (ClinicalTrials.gov, NCT05116189) sponsored by Merck and conducted in collaboration with the European Network for Gynecologic Oncology Trial (ENGOT) groups investigating KEYTRUDA in combination with chemotherapy (paclitaxel) with or without bevacizumab compared to placebo plus chemotherapy with or without bevacizumab for the treatment of platinum-resistant recurrent ovarian cancer. The primary endpoint is PFS, and OS is a key secondary endpoint. The trial enrolled an estimated 643 patients who were randomized to receive:
KEYTRUDA (400 mg intravenously every six weeks for approximately two years) plus paclitaxel with or without bevacizumab, or;
placebo plus paclitaxel with or without bevacizumab.
About ovarian cancer:
Ovarian cancer often begins in the fallopian tubes or on the outer surface of the ovaries. It is the third most common gynecologic malignancy and seventh most common cancer in women worldwide. Globally, there were approximately 324,603 patients diagnosed with ovarian cancer and about 206,956 deaths from the disease in 2022. In the U.S., it is estimated there will be approximately 20,890 patients diagnosed with ovarian cancer and about 12,730 deaths from the disease in 2025. The primary aim of first-line treatment is to delay disease progression for as long as possible with the intent to achieve long-term remission.
About Merck’s research in women’s cancers:
Merck is advancing research aimed at expanding treatment options for certain breast and gynecologic (ovarian, cervical and endometrial) cancers, with a goal of improving outcomes for more patients affected by these diseases. Breast cancer and gynecological cancers are the first and second most commonly occurring cancer types among women worldwide, respectively, and Merck aims to give patients facing these devastating diseases options. With more than 20 clinical trials in more than 18,000 patients around the world, Merck is driving innovative research to purposefully advance standards of care in women’s cancers. Merck’s research efforts include trials focused on evaluating its medicines in earlier stages, as well as identifying novel mechanisms and new combinations with these treatments. Merck is working to develop a portfolio and pipeline to address the impact of women’s cancers on patients, their families and communities globally.
About KEYTRUDA® (pembrolizumab) injection, 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.
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 25 novel mechanisms. With one of the largest clinical development programs across more than 30 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. For more information, visit www.merck.com/research/oncology.
For more information, visit www.merck.com
