Introduction/Background We report on the first patient to our knowledge, to receive all three approved PARP-inhibitors as part of treatment for relapsed ovarian cancer. The 71-year-old was diagnosed with high-grade serous ovarian carcinoma (HGSOC), FIGO stage IIIB, BRCA-1 positive, in 2013 and underwent extensive treatment for almost ten years. First-line therapy included six cycles of carboplatin-paclitaxel plus bevacizumab between January and May, 2013 followed by maintenance therapy with bevacizumab until March, 2014. After relapsing in June, 2017 the patient underwent salvage surgery with complete resection and platinum rechallenge therapy with six cycles of carboplatin-caelyx plus bevacizumab. As maintenance therapy all three PARP-inhibitors were used consecutively from May, 2018 two of which had to be discontinued due to side effects. First niraparib following recurrent thrombocytopenia, then olaparib for abdominal pain. To enable treatment with a PARP-inhibitor, she received rucaparib from October, 2018 until her second relapse in June, 2020. After another salvage surgery with complete resection she was given three cycles of carboplatin and one cycle of cisplatin from September, 2020 to January, 2021. She has received maintenance therapy with rucaparib since March, 2021 with manageable side effects.

Methodology Patient‘s file, Excel, patient interview

Results Rucaparib caused a slower and smaller decrease in platelet count. Transaminases only increased slightly without reaching adverse effect level according to CTCAE, making it an asymptomatic laboratory finding.

Conclusion This report gives an example of how to manage potential side effects during PARP-inhibitor therapy in routine clinical practice. Even after intolerance of two PARP-inhibitors, another was tolerated, showing that switching PARP-inhibitors during therapy is possible. Patients react differently to side effects of PARP-inhibitors, further studies should focus on predictive clinical and pharmacodynamic parameters to identify individual toxicity for optimization of the efficacy of PARP-inhibitors.