Triplet therapy with rucaparib, bevacizumab, and atezolizumab is feasible, demonstrating clinically meaningful improvement in response with acceptable safety for patients with recurrent endometrial cancer, according to a phase 2 trial.

These findings were presented at the 2022 ASCO Annual Meeting by William Bradley, MD, Froedtert and the Medical College of Wisconsin, Milwaukee.

“Patients with metastatic recurrent endometrial cancer have limited effective therapies,” wrote Dr Bradley and colleagues.

 “Single agent pembrolizumab is utilized in mismatch repair deficient patients, while the combination of lenvatinib and pembrolizumab is now more commonly used in [mismatch repair] intact patients who have progressed after chemotherapy combinations,” they continued.

This phase 2 trial enrolled 30 patients with recurrent endometrial cancer not amendable to curative intent surgery or radiation after 1 or 2 lines of therapy. All patients received rucaparib, bevacizumab, and atezolizumab until disease progression, toxicity, or physician choice. Patients were evaluable if they received at least 1 cycle of study treatment and have 1 post-dose tumor assessment.

The primary objective of the trial was to estimate the overall response rate (ORR). A secondary objective was to estimate progression-free survival (PFS) and overall survival (OS).

At a median follow-up of 14.9 months, 23 patients experienced clinical benefit with 1 (4%) patient with a complete response, 9 (39%) patients with a partial response, and 13 (57%) patients with stable disease. Median PFS was 5.3 months 5.3 months and overall survival 13.3 months at cut off. Median duration of therapy was 4.4 months with 4 patients still on study directed therapy at data cut off.

Grade 3 or 4 treatment-related adverse events occurred in 50% patients.

“To our knowledge, this trial represents the first use of a non-chemotherapy-based triplet therapy for recurrent endometrial cancer. The combination of rucaparib, bevacizumab, and atezolizumab may safely be used to treat recurrent/persistent endometrial cancer,” concluded Dr Bradley and colleagues.

“This combination demonstrates clinically meaningful improvement in response, with acceptable toxicity,” they added.

Source:

Bradley WH, Hayes MP, Taylor N, et al. An open label, nonrandomized, multisite phase II trial combining bevacizumab, atezolizumab, and rucaparib for the treatment of previously treated recurrent and progressive endometrial cancer. Presented at: ASCO Annual Meeting; June 3-7, 2022. Chicago, IL, and virtual. Abstract 5510.