Background and importance Poly (ADP-ribose) polymerase inhibitors (PARPi) are used for maintenance therapy in ovarian cancer after a platinum-sensitive relapse. Treatment individualisation is crucial due to the frequency of adverse events (AEs).

Aim and objectives To assess the safety of PARPi for maintenance treatment in ovarian cancer. To compare the obtained results with reference trials.

Material and methods Retrospective observational study from March 2020 to March 2021. All ovarian cancer patients that received PARPi for maintenance after platinum-based chemotherapy were included. Collected data: age, prescribed PARPi and dose, previous chemotherapy lines, BRCA mutational status, AEs and grade according to Common Tterminology Criteria for Adverse Events (CTCAE), time until grade 3 or greater AEs and management. Data were collected from digital clinical history. Reference trials: olaparib: SOLO2/ENGOT-Ov21; niraparib: NOVA/ENGOT-Ov21. Rucaparib comparison was excluded due to a shortage of patients.

Results 40 patients included: olaparib (20), niraparib (18), rucaparib (2). All patients started PARPi therapy with standard dose. Mean age: 55 (range: 37–74) years. Mean chemotherapy regimens received: 3. Patients that did not presented BRCA mutation started treatment with niraparib. 86% patients suffered AEs, of which 62.5% were classified as grade 3. Olaparib: 93% patients presented AEs, grade 3: 50%. Niraparib: 75% presented AEs, grade 3: 66%. Rucaparib: 100% presented grade 3 AEs. Of the total grade 3 AEs reported: 50% were haematological toxicity (olaparib: 14%, niraparib: 83%, rucaparib: 50%), 25% were gastrointestinal toxicity (olaparib 43%, rucaparib 50%) and the remaining 25% were other toxicity (olaparib 43%, niraparib 17%). Mean time until first appearance of grade 3 toxicity: 5.4 months and 4-month median. 65% patients required a dose reduction due to AEs (olaparib: 36%, niraparib: 41%, rucaparib: 100%) of which 6 patients discontinued PARPi due to a second major haematological AE: niraparib (5), rucaparib (1). Both trials SOLO2/ENGOT-Ov21 and NOVA/ENGOT-Ov21 showed an overall less AE incidence.

Conclusion and relevance AEs related to PARPi therapy are common, and more than the half of the patients required a dose reduction. These findings are in line with both trials. However, in contrast with the revised trials, we report an overall higher AEs incidence, haematological AEs being the main concern specially with niraparib. More studies are needed to improve the PARPi tolerance without compromising efficacy.

Conflict of interest No conflict of interest