Abstract Code: IUC24434-82

Real-World Use of Abiraterone and Olaparib in Metastatic Castration-Resistant Prostate Cancer (mCRPC): A Two-Centre UK Experience

M.  Ali Hassan ¹, J. Kadamala Samuel ², M. Maffezzoli ³, N. Kolambil Saidalavi ³, R. Arora ³, S. Sandulache ³, F. Di Costanzo ⁴, A. Maniam ³, G. Luigi Banna ¹

(1) Portsmouth Hospital University NHS trust – United Kingdom, (2) Portsmouth Hospital University NHS trust – United Kingdom, (3) Portsmouth Hospital University NHS trust – United Kingdom, (4) Newcastle Hospitals NHS Foundation trust – United Kingdom

Background: Metastatic castration-resistant prostate cancer (mCRPC) remains a therapeutic challenge, with limited long-term treatment options. In December 2023, NICE approved the combination of olaparib and abiraterone for mCRPC based on the PROpel trial, which demonstrated a significant improvement in radiographic progression-free survival. However, real-world data on the effectiveness and tolerability of this combination are lacking. To our knowledge, this is the first UK-based real-world study evaluating this regimen in contemporary patients.

Methods: We conducted a retrospective chart review of patients with mCRPC treated with abiraterone and Olaparib (Abi-Ola) between December 2023 and June 2025 at two UK centres: Portsmouth Hospitals University NHS Trust and Newcastle Hospitals NHS Trust. Demographics, disease characteristics, prior treatments, treatment tolerability, and adverse events were analysed.

Results: A total of 36 patients were included. The median age was 69 years (52-84). At baseline, 25 patients (69.4%) had ECOG performance status (PS) 0, and 11 (30.5%) had PS 1. The median PSA at diagnosis was 240 ng/mL. Prior treatments, disease setting at mCRPC diagnosis, Abi-Ola treatment discontinuation, dose reduction and toxicity are summarised in the Table. Twenty-eight patients (77.8%) had previous docetaxel. Before initiating therapy, only 2 patients had G1 anaemia.

With a median follow-up of 11.1 months (95% CI 9.9-15.4), 3 patients (8.3%) had died, and 9 (25.0%) discontinued Ola-Abi due to disease progression. Treatment discontinuation due to toxicity occurred in 8 patients (22.2%), with 1 patient stopping both agents and 7 patients discontinuing Ola alone. Dose reductions were required in 12 patients (33.3%): 11 for Ola and 1 for both agents. Anaemia was observed in 14 patients (38.8%), with 10 experiencing Grade (G) 1, 2 G2, and 2 G3 severity. The other most common side effects observed were fatigue in 20 patients (55.5%; 13 G1, 7 G2), and nausea in 9 patients (25.0%; all G1).

Conclusions: This real-world analysis suggests that the combination of Abi-Ola is feasible and generally well tolerated in the mCRPC setting, with manageable toxicity profiles similar to those reported in the PROpel trial. Further follow-up and comparison with clinical trial outcomes are warranted to validate efficacy and long-term safety in broader clinical practice and in patients’ subgroups.