Study also met secondary endpoint of overall survival (OS) for patients whose tumors express PD-L1
KEYTRUDA® (pembrolizumab) plus chemotherapy (paclitaxel) with or without bevacizumab is the first immune checkpoint inhibitor-based regimen to show a statistically significant improvement in OS for ovarian cancer
RAHWAY, NJ, USA I May 15, 2025 I Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today 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.
Selected KEYTRUDA® (pembrolizumab) Indications in the U.S.
Melanoma
KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic melanoma.
KEYTRUDA is indicated for the adjuvant treatment of adult and pediatric (12 years and older) patients with Stage IIB, IIC, or III melanoma following complete resection.
Non-Small Cell Lung Cancer
KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of patients with metastatic nonsquamous non-small cell lung cancer (NSCLC), with no EGFR or ALK genomic tumor aberrations.
KEYTRUDA, in combination with carboplatin and either paclitaxel or paclitaxel protein-bound, is indicated for the first-line treatment of patients with metastatic squamous NSCLC.
KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with NSCLC expressing PD-L1 [Tumor Proportion Score (TPS) ≥1%] as determined by an FDA-approved test, with no EGFR or ALK genomic tumor aberrations, and is:
- Stage III where patients are not candidates for surgical resection or definitive chemoradiation, or
- metastatic.
KEYTRUDA, as a single agent, is indicated for the treatment of patients with metastatic NSCLC whose tumors express PD-L1 (TPS ≥1%) as determined by an FDA-approved test, with disease progression on or after platinum-containing chemotherapy. Patients with EGFR or ALK genomic tumor aberrations should have disease progression on FDA-approved therapy for these aberrations prior to receiving KEYTRUDA.
KEYTRUDA is indicated for the treatment of patients with resectable (tumors ≥4 cm or node positive) NSCLC in combination with platinum-containing chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery.
KEYTRUDA, as a single agent, is indicated as adjuvant treatment following resection and platinum-based chemotherapy for adult patients with Stage IB (T2a ≥4 cm), II, or IIIA NSCLC.
Malignant Pleural Mesothelioma
KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of adult patients with unresectable advanced or metastatic malignant pleural mesothelioma (MPM).
Head and Neck Squamous Cell Cancer
KEYTRUDA, in combination with platinum and fluorouracil (FU), is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent head and neck squamous cell carcinoma (HNSCC).
KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC whose tumors express PD-L1 [Combined Positive Score (CPS) ≥1] as determined by an FDA-approved test.
KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic HNSCC with disease progression on or after platinum-containing chemotherapy.
Classical Hodgkin Lymphoma
KEYTRUDA is indicated for the treatment of adult patients with relapsed or refractory classical Hodgkin lymphoma (cHL).
KEYTRUDA is indicated for the treatment of pediatric patients with refractory cHL, or cHL that has relapsed after 2 or more lines of therapy.
Primary Mediastinal Large B-Cell Lymphoma
KEYTRUDA is indicated for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL), or who have relapsed after 2 or more prior lines of therapy. KEYTRUDA is not recommended for treatment of patients with PMBCL who require urgent cytoreductive therapy.
Urothelial Cancer
KEYTRUDA, in combination with enfortumab vedotin, is indicated for the treatment of adult patients with locally advanced or metastatic urothelial cancer.
KEYTRUDA, as a single agent, is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma:
- who are not eligible for any platinum-containing chemotherapy, or
- who have disease progression during or following platinum-containing chemotherapy or within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy.
KEYTRUDA, as a single agent, is indicated for the treatment of patients with Bacillus Calmette-Guerin (BCG)-unresponsive, high-risk, non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) with or without papillary tumors who are ineligible for or have elected not to undergo cystectomy.
Microsatellite Instability-High or Mismatch Repair Deficient Cancer
KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options.
Microsatellite Instability-High or Mismatch Repair Deficient Colorectal Cancer
KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC) as determined by an FDA-approved test.
Gastric Cancer
KEYTRUDA, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.
KEYTRUDA, in combination with fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma.
Esophageal Cancer
KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic esophageal or gastroesophageal junction (GEJ) (tumors with epicenter 1 to 5 centimeters above the GEJ) carcinoma that is not amenable to surgical resection or definitive chemoradiation either:
- in combination with platinum- and fluoropyrimidine-based chemotherapy, or
- as a single agent after one or more prior lines of systemic therapy for patients with tumors of squamous cell histology that express PD-L1 (CPS ≥10) as determined by an FDA-approved test.
Cervical Cancer
KEYTRUDA, in combination with chemoradiotherapy (CRT), is indicated for the treatment of patients with FIGO 2014 Stage III-IVA cervical cancer.
KEYTRUDA, in combination with chemotherapy, with or without bevacizumab, is indicated for the treatment of patients with persistent, recurrent, or metastatic cervical cancer whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.
KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic cervical cancer with disease progression on or after chemotherapy whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test.
Hepatocellular Carcinoma
KEYTRUDA is indicated for the treatment of patients with hepatocellular carcinoma (HCC) secondary to hepatitis B who have received prior systemic therapy other than a PD-1/PD-L1-containing regimen.
Biliary Tract Cancer
KEYTRUDA, in combination with gemcitabine and cisplatin, is indicated for the treatment of patients with locally advanced unresectable or metastatic biliary tract cancer (BTC).
Merkel Cell Carcinoma
KEYTRUDA is indicated for the treatment of adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC).
Renal Cell Carcinoma
KEYTRUDA, in combination with axitinib, is indicated for the first-line treatment of adult patients with advanced renal cell carcinoma (RCC).
KEYTRUDA is indicated for the adjuvant treatment of patients with RCC at intermediate-high or high risk of recurrence following nephrectomy, or following nephrectomy and resection of metastatic lesions.
Endometrial Carcinoma
KEYTRUDA, in combination with carboplatin and paclitaxel, followed by KEYTRUDA as a single agent, is indicated for the treatment of adult patients with primary advanced or recurrent endometrial carcinoma.
KEYTRUDA, as a single agent, is indicated for the treatment of adult patients with advanced endometrial carcinoma that is MSI-H or dMMR, as determined by an FDA-approved test, who have disease progression following prior systemic therapy in any setting and are not candidates for curative surgery or radiation.
Tumor Mutational Burden-High Cancer
KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic tumor mutational burden-high (TMB-H) [≥10 mutations/megabase (mut/Mb)] solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options.
This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials. The safety and effectiveness of KEYTRUDA in pediatric patients with TMB-H central nervous system cancers have not been established.
Cutaneous Squamous Cell Carcinoma
KEYTRUDA is indicated for the treatment of patients with recurrent or metastatic cutaneous squamous cell carcinoma (cSCC) or locally advanced cSCC that is not curable by surgery or radiation.
Triple-Negative Breast Cancer
KEYTRUDA is indicated for the treatment of patients with high-risk early-stage triple-negative breast cancer (TNBC) in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery.
KEYTRUDA, in combination with chemotherapy, is indicated for the treatment of patients with locally recurrent unresectable or metastatic TNBC whose tumors express PD-L1 (CPS ≥10) as determined by an FDA-approved test.
Please see Prescribing Information for KEYTRUDA (pembrolizumab) at http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_pi.pdf and Medication Guide for KEYTRUDA at http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_mg.pdf.
About LYNPARZA® (olaparib)
LYNPARZA is a first-in-class PARP inhibitor and the first targeted treatment to potentially exploit DNA damage response (DDR) pathway deficiencies, such as BRCA mutations, to preferentially kill cancer cells. Inhibition of PARP with LYNPARZA leads to the trapping of PARP bound to DNA single-strand breaks, stalling of replication forks, their collapse and the generation of DNA double-strand breaks and cancer cell death. LYNPARZA is being tested in a range of tumor types with defects and dependencies in the DDR.
LYNPARZA, which is being jointly developed and commercialized by AstraZeneca and Merck, has a broad clinical trial development program, and AstraZeneca and Merck are working together to understand how it may affect multiple PARP-dependent tumors as a monotherapy and in combination across multiple cancer types. Independently, Merck is developing LYNPARZA in combination with its anti-PD-1 therapy, KEYTRUDA.
INDICATIONS
LYNPARZA is a poly (ADP-ribose) polymerase (PARP) inhibitor indicated:
First-Line Maintenance BRCAm Advanced Ovarian Cancer
For the maintenance treatment of adult patients with deleterious or suspected deleterious germline or somatic BRCA-mutated (gBRCAm or sBRCAm) advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to first-line platinum-based chemotherapy. Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
First-Line Maintenance HRD-Positive Advanced Ovarian Cancer in Combination with Bevacizumab
In combination with bevacizumab for the maintenance treatment of adult patients with advanced epithelial ovarian, fallopian tube or primary peritoneal cancer who are in complete or partial response to first-line platinum-based chemotherapy and whose cancer is associated with homologous recombination deficiency (HRD)-positive status defined by either:
- a deleterious or suspected deleterious BRCA mutation, and/or
- genomic instability
Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
Maintenance BRCA-mutated Recurrent Ovarian Cancer
For the maintenance treatment of adult patients with deleterious or suspected deleterious germline or somatic BRCA-mutated (gBRCAm or sBRCAm) recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, who are in complete or partial response to platinum-based chemotherapy. Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
Adjuvant Treatment of gBRCAm, HER2-Negative, High-Risk Early Breast Cancer
For the adjuvant treatment of adult patients with deleterious or suspected deleterious gBRCAm, human epidermal growth factor receptor 2 (HER2)-negative, high-risk early breast cancer who have been treated with neoadjuvant or adjuvant chemotherapy. Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
gBRCAm, HER2-Negative Metastatic Breast Cancer
For the treatment of adult patients with deleterious or suspected deleterious gBRCAm, human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer who have been treated with chemotherapy in the neoadjuvant, adjuvant, or metastatic setting. Patients with hormone receptor (HR)-positive breast cancer should have been treated with a prior endocrine therapy or be considered inappropriate for endocrine therapy. Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
First-Line Maintenance gBRCAm Metastatic Pancreatic Cancer
For the maintenance treatment of adult patients with deleterious or suspected deleterious gBRCAm metastatic pancreatic adenocarcinoma whose disease has not progressed on at least 16 weeks of a first-line platinum-based chemotherapy regimen. Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
HRR Gene-mutated Metastatic Castration-Resistant Prostate Cancer
For the treatment of adult patients with deleterious or suspected deleterious germline or somatic homologous recombination repair (HRR) gene-mutated metastatic castration-resistant prostate cancer (mCRPC) who have progressed following prior treatment with enzalutamide or abiraterone. Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
BRCAm Metastatic Castration-Resistant Prostate Cancer in Combination with Abiraterone and Prednisone or Prednisolone
In combination with abiraterone and prednisone or prednisolone (abi/pred) for the treatment of adult patients with deleterious or suspected deleterious BRCA-mutated (BRCAm) metastatic castration-resistant prostate cancer (mCRPC). Select patients for therapy based on an FDA-approved companion diagnostic for LYNPARZA.
Please see complete Prescribing Information, including Medication Guide.
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.
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. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.
SOURCE: Merck