FDA approves the first immunotherapy regimen for platinum-resistant ovarian cancer with a proven survival benefit
In plain English
The 30-second version
What happened?
In the randomized, phase 3 ENGOT-ov65/KEYNOTE-B96 trial, adding pembrolizumab to paclitaxel chemotherapy significantly improved BOTH progression-free survival (8.3 vs 7.2 months) AND overall survival (18.2 vs 14.0 months) in patients with PD-L1-positive, platinum-resistant ovarian cancer -- the first immune checkpoint inhibitor regimen to show a statistically significant survival benefit in a phase 3 ovarian cancer trial.
Why does it matter?
Ovarian cancer has historically shown disappointing results with immune checkpoint inhibitors compared with other cancer types -- a confirmed, statistically significant survival benefit in a well-powered, randomized phase 3 trial is a genuine, meaningful advance for a population with historically very limited options, and adds real depth to this site's ovarian cancer coverage.
What does this not prove?
This approval is specifically for PD-L1-POSITIVE (CPS >=1) disease, confirmed by a companion diagnostic test -- it does not apply to PD-L1-negative platinum-resistant ovarian cancer, for which this specific benefit was not demonstrated. Platinum-resistant disease is a specific clinical category (recurrence within 6 months of platinum-based chemotherapy) -- this record makes no claim about platinum-sensitive disease.
Keep reading for evidence stage, limitations, study details, and sources.
The FDA approved pembrolizumab (Keytruda) in combination with paclitaxel, with or without bevacizumab, for adults with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma who have received one to two prior lines of systemic therapy and whose tumors express PD-L1 (CPS >=1, per a companion diagnostic test) — the first immune checkpoint inhibitor regimen to demonstrate a statistically significant overall-survival benefit in a phase 3 ovarian cancer trial. The approval was based on the randomized, double-blind, phase 3 ENGOT-ov65/KEYNOTE-B96 trial (ClinicalTrials.gov NCT05116189; primary publication in The Lancet, DOI 10.1016/S0140-6736(26)00602-1, PMID 41974150), conducted at 187 gynaecologic oncology centres in 25 countries and enrolling 643 patients. Among PD-L1-positive participants, progression-free survival improved from 7.2 to 8.3 months (hazard ratio 0.72, P=.0014) and overall survival improved from 14.0 to 18.2 months (hazard ratio 0.76, P=.0053) with pembrolizumab added — real, statistically significant benefits on both endpoints.
Population / Applicability
Studied in: Adults with platinum-resistant, PD-L1-positive (CPS >=1) epithelial ovarian, fallopian tube, or primary peritoneal carcinoma who had received one to two prior lines of systemic therapy, randomized to pembrolizumab plus paclitaxel (+/- bevacizumab) or placebo plus paclitaxel (+/- bevacizumab), in the randomized, double-blind, phase 3 ENGOT-ov65/KEYNOTE-B96 trial conducted at 187 sites in 25 countries. (Adults)
Requires PD-L1 testing (CPS >=1) before use via a companion diagnostic. This record has not independently reviewed the full safety/tolerability profile.
Full evidence details
- Study design
- Randomized controlled trial
- Sample size
- 643
Funding & Conflicts
Sponsor/developer: Merck & Co., Inc. -- not independently confirmed against a primary corporate-disclosure document.
Regulatory status by jurisdiction
United States (FDA)
- Status
- FDA-approved for the exact stated cancer/use
- Indication
- Adults with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma whose tumors express PD-L1 (CPS >=1), who have received one to two prior lines of systemic therapy.
- Biomarker requirement
- PD-L1 CPS >=1 (PD-L1 IHC 22C3 pharmDx)
- Decision date
- 2026-02-10
Guideline positions
Guideline
- Position
- Not addressed
- Last verified
- 2026-08-13
Primary evidence supporting this story
- Pembrolizumab plus weekly paclitaxel in platinum-resistant recurrent ovarian cancer (ENGOT-ov65/KEYNOTE-B96): a multicentre, randomised, double-blind, phase 3 study (The Lancet) (opens in a new tab) (Peer-reviewed paper) [Peer-reviewed] 10.1016/S0140-6736(26)00602-1 Primary source DOI 10.1016/S0140-6736(26)00602-1, PMID 41974150
Pembrolizumab plus weekly paclitaxel in platinum-resistant recurrent ovarian cancer (ENGOT-ov65/KEYNOTE-B96): a multicentre, randomised, double-blind, phase 3 study (The Lancet). DOI 10.1016/S0140-6736(26)00602-1, PMID 41974150.
Additional context
- ENGOT-ov65/KEYNOTE-B96 trial registry (opens in a new tab) (Clinical-trial registry) NCT05116189 NCT05116189
ENGOT-ov65/KEYNOTE-B96 trial registry. NCT05116189.
Last reviewed
FDA approves the first immunotherapy regimen for platinum-resistant ovarian cancer with a proven survival benefit
https://cancerdiscoveries.com/discoveries/fda-approves-the-first-immunotherapy-regimen-for-platinum-resistant-ovarian-cancer-with-a-proven-survival-benefit/
Research type: Later-stage studies in people
What This Means
In the randomized, phase 3 ENGOT-ov65/KEYNOTE-B96 trial, adding pembrolizumab to paclitaxel chemotherapy significantly improved BOTH progression-free survival (8.3 vs 7.2 months) AND overall survival (18.2 vs 14.0 months) in patients with PD-L1-positive, platinum-resistant ovarian cancer -- the first immune checkpoint inhibitor regimen to show a statistically significant survival benefit in a phase 3 ovarian cancer trial.
What This Doesn't Mean
This approval is specifically for PD-L1-POSITIVE (CPS >=1) disease, confirmed by a companion diagnostic test -- it does not apply to PD-L1-negative platinum-resistant ovarian cancer, for which this specific benefit was not demonstrated. Platinum-resistant disease is a specific clinical category (recurrence within 6 months of platinum-based chemotherapy) -- this record makes no claim about platinum-sensitive disease.
Why It Matters
Ovarian cancer has historically shown disappointing results with immune checkpoint inhibitors compared with other cancer types -- a confirmed, statistically significant survival benefit in a well-powered, randomized phase 3 trial is a genuine, meaningful advance for a population with historically very limited options, and adds real depth to this site's ovarian cancer coverage.
Primary sources
- Pembrolizumab plus weekly paclitaxel in platinum-resistant recurrent ovarian cancer (ENGOT-ov65/KEYNOTE-B96): a multicentre, randomised, double-blind, phase 3 study (The Lancet) — https://doi.org/10.1016/S0140-6736(26)00602-1 (DOI 10.1016/S0140-6736(26)00602-1, PMID 41974150)
Date verified: 2026-08-13
Correction status: No correction or retraction