FDA Grants Fast Track Designation to BI-1808 Plus Pembrolizumab in Ovarian Cancer

The FDA has granted fast track designation to BI-1808, a first-in-class anti-TNFR2 antibody, in combination with pembrolizumab (Keytruda) for the treatment of patients with ovarian cancer.¹

The designation was supported by interim findings from the combination cohort of the ongoing phase 2a study (NCT04752826), in which BI-1808 plus pembrolizumab generated a confirmed objective response rate (ORR) of 24% and a disease control rate (DCR) of 56% in heavily pretreated patients with advanced platinum-resistant ovarian cancer, according to data presented at the 2026 ASCO Annual Meeting.^1,2 Responses comprised 1 complete response and 5 partial responses, along with 8 patients who experienced stable disease. A preliminary analysis showed a median progression-free survival (PFS) of 10.3 months, with responses observed across both high-grade serous and clear cell subtypes.

“Receiving FDA Fast Track Designation for BI-1808 in ovarian cancer is an important milestone that reflects the significant unmet medical need in this difficult-to-treat disease and the strength of the clinical signals we have generated to date,” Martin Welschof, chief executive officer of BioInvent, satated in a news release.¹

The company reported that cohort expansion is underway, focusing on the high-grade serous and clear cell subtypes, with an additional data readout expected in the second half of 2026.¹

What is the mechanism of action of BI-1808?

BI-1808 is a first-in-class IgG1 monoclonal antibody targeting TNFR2, a receptor that is particularly upregulated on regulatory T cells (Tregs) within the tumor microenvironment.^1,2 The antibody blocks TNF-α binding and, through FcγR engagement, depletes immunosuppressive Tregs and reprograms myeloid cells, resulting in the expansion of antitumor CD8-positive T cells.

In preclinical models, BI-1808 synergized with anti–PD-1 therapy, producing additive tumor inhibition that provided the rationale for combining the agent with pembrolizumab in the clinic.²

The activity observed with the combination builds on continued efforts to extend checkpoint inhibition into platinum-resistant ovarian cancer, a setting in which single-agent PD-1 blockade has shown limited benefit. Sacituzumab govitecan-hziy (Trodelvy) recently generated an ORR of 35% in heavily pretreated platinum-resistant disease in a separate phase 2 study (NCT06028932),³ and PD-L1 IHC 22C3 pharmDx was cleared in the European Union as a companion diagnostic for pembrolizumab in platinum-resistant epithelial ovarian cancer.⁴

How was the BI-1808 trial designed?

The ongoing phase 2a study is evaluating BI-1808 as a single agent (Part A), in combination with pembrolizumab (Part B), and in a triple combination with pembrolizumab plus paclitaxel (Part C).¹ The trial aims to enroll 20 patients in the monotherapy cohort and 40 patients in the combination cohort.²

All enrolled patients had recurrent ovarian cancer and had previously received at least one platinum-containing regimen.² Patients were treated with BI-1808 at 1000 mg with or without pembrolizumab at 200 mg every 3 weeks for up to 2 years.²

The study is designed to characterize safety, pharmacokinetics, and pharmacodynamics, and to assess preliminary antitumor activity by ORR, duration of response, and PFS, as measured by RECIST v1.1 and iRECIST criteria.¹

What did the safety data demonstrate?

Across 74 patients with solid tumors who received BI-1808 plus pembrolizumab, the combination was well tolerated, with manageable immune-related adverse effects, a low rate of grade 3 or higher adverse effects, and a treatment-related discontinuation rate of less than 5%.²

References

1. BioInvent receives FDA fast track designation for BI-1808 for the treatment of ovarian cancer. News release. BioInvent International AB. August 7, 2026. Accessed August 7, 2026. https://www.bioinvent.com/en/press/bioinvent-receives-fda-fast-track-designation-bi-1808-treatment-ovarian-cancer-2472829

2. Kristelleit R, Williams A, Lopez J, et al. BI-1808 + pembrolizumab: responses to a chemotherapy-free regimen in advanced ovarian cancer. J Clin Oncol. 2026;44(suppl 16):2605. doi:10.1200/JCO.2026.44.16_suppl.2605

3. Sacituzumab govitecan yields responses in platinum-resistant ovarian cancer. OncLive. Published July 22, 2026. Accessed August 7, 2026. https://www.onclive.com/view/sacituzumab-govitecan-yields-responses-in-platinum-resistant-ovarian-cancer

4. EU clears PD-L1 IHC 22C3 pharmDx as companion diagnostic for pembrolizumab in ovarian cancer. OncLive. Published August 6, 2026. Accessed August 7, 2026. https://www.onclive.com/view/eu-clears-pd-l1-ihc-22c3-pharmdx-as-companion-diagnostic-for-pembrolizumab-in-ovarian-cancer