Dostarlimab (modestly) improves progression-free survival in advanced ovarian cancer

The addition of the programmed cell death protein-1 (PD-1) inhibitor dostarlimab to first-line platinum-based chemotherapy and maintenance niraparib is associated with a statistically significant, albeit clinically modest, improvement in progression-free survival (PFS), according to the phase 3 FIRST/ENGOT-OV44 trial.

Preclinical evidence suggests that inhibitors of PD-1 and programmed cell death-ligand 1 (PD-L1) result in improved activity in advanced ovarian cancer when combined with chemotherapy, anti-VEGF therapy using bevacizumab, or PARP inhibitors [1]. Moreover, results from early-phase clinical trials showed a manageable safety profile and a modest efficacy signal for PD-(L)1 inhibitors in participants with relapsed advanced ovarian cancer when combined with a PARP inhibitor [2].

From these promising results, the FIRST/ENGOT-OV44 trial (NCT03602859) evaluated the addition of PD-1 inhibitor dostarlimab to first-line platinum-based chemotherapy and niraparib maintenance (with or without bevacizumab) in participants with newly diagnosed advanced ovarian cancer. Dr Anne-Claire Hardy-Bessard (Centre Armoricain d'Oncologie, France) presented the results [3].

A total of 1162 participants were 1:2 randomised to receive chemotherapy followed by niraparib maintenance or additional dostarlimab combined with chemotherapy and niraparib maintenance. The primary endpoint was progression-free survival (PFS).

The addition of dostarlimab to the chemotherapy and niraparib maintenance regimen statistically significantly improved PFS, albeit with clinically small effects. The median PFS was 20.6 months (95% CI 19.2–22.8) versus 19.2 months (95% CI 16.2–21.0) with or without dostarlimab, respectively (HR 0.85; 95% CI 0.73–0.99; P=0.0351). No improvement was observed between arms in overall survival, nor were there any meaningful differences in quality-of-life.

“Addition of dostarlimab to the standard treatment of participants with newly diagnosed advanced ovarian cancer comes with a statistically significant, but clinically modest improvement”, Dr Hardy-Bessard concluded.

1. Huang J, et al. Biochem Biophys Res Commun. 2015;463(4):551–556.
2. Lee J-M, et al. Ann Oncol. 2018;29(suppl 8):VIII334.
3. Hardy-Bessard AC, et al. FIRST/ENGOT-OV44: A phase 3 clinical trial of dostarlimab (dost) and niraparib (nira) in first-line (1L) advanced ovarian cancer (aOC). Abstract LBA5506, ASCO Annual Meeting 2025, May 30–June 3, Chicago, IL, USA.

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Posted on 30 July 2025