Real-World Use of Dostarlimab in Endometrial Cancer: A Portuguese Multicenter Study.

Abstract

Introduction: Dostarlimab has been available in Portugal for advanced or recurrent endometrial cancer post-platinum therapy via an early access program (EAP) since November 2021, with reimbursement from October 2024; its use with carboplatin and paclitaxel was authorized under an early access program in June 2024. The aim of this study was to assess the efficacy and safety of dostarlimab in a Portuguese cohort of endometrial cancer patients.

Methods: This is a national multicenter retrospective cohort study involving patients treated with dostarlimab between January 2022 and January 2025 in 13 hospitals. Safety endpoints were rate of grade ≥ 3 adverse events (AE) and the treatment discontinuation rate. Efficacy endpoints were disease control rate (DCR), overall response rate (ORR) and six-month progression-free survival (PFS), in the monotherapy and the chemotherapy-combination groups.

Results: The study assessed 43 patients, with a median follow-up time of six (3 - 14) months. In the chemotherapy-combination group (n = 13), mean age was 62.77 ± 8.4 years-old; the most common histological subtype was endometrioid (69.2%), but 23.1% were carcinosarcoma. Both ORR and DCR were 84.6%. In the monotherapy group (n = 30), the median number of previous treatment lines was 1 (1 - 6). Mean age was 67.43 ± 9.44 years. Endometrioid was the most prevalent histology (83.3%), followed by serous (6.6%). Overall response rate was 53.3% and DCR 63.3%. The six-month PFS was 68.4% (95% CI: 51% - 86%) in the monotherapy group and 83.1% (95% CI: 62% - 100%) in the combination group. Regarding safety, only 13.9% of patients reported grade ≥ 3 AE and the discontinuation rate was 9.3%.

Conclusion: The results show compatible findings with current data regarding efficacy and manageable toxicity and may support the role of an early access program in improving treatment availability for patients with limited therapeutic options.