News|Articles|February 11, 2026

PD-L1 IHC 22C3 pharmDx Nets Companion Diagnostic Approval for Pembrolizumab in Ovarian Cancer

Fact checked by: Caroline Seymour, Kirsty Mackay

Listen

0:00 / 0:00

Key Takeaways

FDA authorized PD-L1 IHC 22C3 pharmDx as the companion diagnostic for pembrolizumab selection in epithelial ovarian, fallopian tube, and primary peritoneal carcinoma based on PD-L1 CPS.
KEYNOTE-B96 enrolled platinum-resistant patients progressing within 6 months of platinum, ECOG 0–1, after 1–2 prior lines; prior anti–PD-1/PD-L1, PARPi, and bevacizumab were allowed.
Randomization compared pembrolizumab 400 mg Q6W (18 cycles) versus placebo, each with weekly paclitaxel 80 mg/m² and optional bevacizumab 10 mg/kg Q2W; PFS was primary, OS key secondary.
In CPS ≥1 tumors, pembrolizumab combinations improved PFS (8.3 vs 7.2 months; HR 0.72) and OS (18.2 vs 14.0 months; HR 0.76) over placebo combinations.
Toxicity was substantial in both arms, with increased grade ≥3 (82.5% vs 70.8%) and serious AEs (55.6% vs 38.4%); common treatment-related events included anemia, neuropathy, and alopecia.

The FDA approved the PD-L1 IHC 22C3 pharmDx as a companion diagnostic for patients with PD-L1–positive ovarian cancer who could receive pembrolizumab.

The FDA has approved the PD-L1 IHC 22C3 pharmDx, Code SK006, as the sole FDA-approved companion diagnostic to aid in identifying treatment-naive patients with epithelial ovarian, fallopian tube, or primary peritoneal carcinoma with PD-L1–expressing tumors who may be eligible for treatment with pembrolizumab (Keytruda).¹

“Delivering effective precision oncology requires close collaboration between diagnostics and therapeutics, and this FDA approval reflects Agilent’s long-standing industry partnership in companion diagnostics,” Nina Green, vice president and general manager of Agilent Technologies’ Clinical Diagnostics Division, stated in a news release. “We are proud to enable pathologists to identify patients with EOC [epithelial ovarian cancer] who may benefit from immunotherapy. As the first immuno-oncology approval for this disease, this milestone underscores our commitment to advancing precision medicine and expanding access to innovative cancer treatments worldwide.”

The diagnostic approval accompanied the February 2026 FDA approval of pembrolizumab as well as pembrolizumab and berahyaluronidase alfa-pmph (Keytruda Qlex) plus paclitaxel, with or without bevacizumab (Avastin), in adult patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma with a PD-L1 combined positive score (CPS) of at least 1, as determined by an FDA-authorized test, and prior receipt of 1 or 2 systemic treatment regimens.²

The regulatory decision was supported by data from the phase 3 KEYNOTE-B96 trial (NCT05116189) which demonstrated that patients with a PD-L1 CPS of at least 1 who received pembrolizumab plus paclitaxel, with or without bevacizumab (n = 234) experienced a median progression-free survival (PFS) of 8.3 months (95% CI, 7.0-9.4) vs 7.2 months (95% CI, 6.2-8.1) with placebo plus paclitaxel, with or without bevacizumab, (n = 232; HR, 0.72; 95% CI, 0.58-0.89; P = .0014).^2,3 The median overall survival (OS) values were 18.2 months (95% CI, 15.3-21.0) and 14.0 months (95% CI, 12.5-16.1), respectively (HR, 0.76; 95% CI, 0.61-0.94; P = .0053). The PD-L1 IHC 22C3 pharmDx was used in KEYNOTE-B96 to identify patients who may have benefited from the pembrolizumab-containing regimen.¹

PD-L1 IHC 22C3 pharmDx Companion Diagnostic Approval: Key Takeaways

The FDA approved the PD-L1 IHC 22C3 pharmDx, Code SK006, as the sole FDA-approved companion diagnostic to aid in identifying treatment-naive patients with epithelial ovarian, fallopian tube, or primary peritoneal carcinoma with PD-L1–expressing tumors who may be eligible for treatment with pembrolizumab.

The regulatory decision occurred in conjunction with the FDA approval of pembrolizumab as well as pembrolizumab and berahyaluronidase alfa-pmph plus paclitaxel, with or without bevacizumab in adult patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma with a PD-L1 CPS of at least 1, as determined by an FDA-authorized test, and prior receipt of 1 or 2 systemic treatment regimens.

In the phase 3 KEYNOTE-B96 trial, patients with a PD-L1 CPS of at least 1, as determined by the PD-L1 IHC 22C3 pharmDx, experienced significant PFS (HR, 0.72; 95% CI, 0.58-0.89; P = .0014) and OS (HR, 0.76; 95% CI, 0.61-0.94; P = .0053) benefits in the pembrolizumab arm compared with the placebo arm.

What were the key design characteristics of KEYNOTE-B96?

KEYNOTE-B96 was a multicenter, randomized, double-blind, placebo-controlled trial that enrolled patients with platinum-resistant, epithelial ovarian, fallopian tube, or primary peritoneal carcinoma who received 1 or 2 prior lines of systemic therapy for ovarian carcinoma.² Eligible patients needed to have experienced radiographic disease progression within 6 months after the last dose of platinum-based chemotherapy and an ECOG performance status of 0 or 1.³ Prior anti–PD-1, anti–PD-L1, PARP inhibition, and bevacizumab were permitted.

Patients were randomly assigned 1:1 to receive pembrolizumab at 400 mg every 6 weeks for 18 cycles or matching placebo, both in combination with paclitaxel at 80 mg/m² on days 1, 8, and 15 of each 3-week cycle, with or without bevacizumab at 10 mg/kg every 2 weeks.

The primary end point was PFS per RECIST 1.1 criteria per investigator assessment. OS was the study’s key secondary end point.

What was the safety profile of the pembrolizumab-containing combination?

Prior safety data from KEYNOTE-B96 presented during the 2025 ESMO Congress demonstrated that any-grade adverse effects (AEs) occurred in the investigational (n = 320) and placebo (n = 318) arms at respective rates of 99.7% and 99.4%. AEs that were grade 3 or higher (82.5% vs 70.8%), serious (55.6% vs 38.4%), led to death (4.7% vs 4.4%), and led to discontinuation of any treatment (41.3% vs 34.0%) were reported in both arms. The most common any-grade treatment-related AEs that occurred in at least 20% of patients included anemia (49.7% vs 42.1%), peripheral neuropathy (38.8% vs 31.1%), and alopecia (37.8% vs 34.0%).

References

Agilent receives FDA approval for PD-L1 IHC 22C3 pharmDx in epithelial ovarian, fallopian tube, or primary peritoneal carcinoma (EOC). News release. Agilent Technologies. February 11, 2026. Accessed February 11, 2026. https://www.investor.agilent.com/news-and-events/news/news-details/2026/Agilent-Receives-FDA-Approval-for-PD-L1-IHC-22C3-pharmDx-in-Epithelial-Ovarian-Fallopian-Tube-or-Primary-Peritoneal-Carcinoma-EOC/default.aspx
FDA approves pembrolizumab with paclitaxel for platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal carcinoma. FDA. February 10, 2026. Accessed February 11, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-pembrolizumab-paclitaxel-platinum-resistant-epithelial-ovarian-fallopian-tube-or?utm_medium=email&utm_source=govdelivery
Colombo N, Zsiros E, Sebastianelli A, et al. Pembrolizumab vs placebo plus weekly paclitaxel ± bevacizumab in platinum-resistant recurrent ovarian cancer: results from the randomized double-blind phase III ENGOT-ov65/KEYNOTE-B96 study. Ann Oncol. 2025;36(suppl 2):S1582. doi:10.1016/j.annonc.2025.09.049