Adjuvant olaparib real world data for BRCA positive, HER2-negative high-risk early breast cancer patients in the United Kingdom.

IntroductionSince 2023 olaparib has been commissioned in the United Kingdom for breast cancer for patients with breast cancer gene 1 and 2 (BRCA1 and 2) positive, human epidermal growth factor receptor 2 (HER2)-negative, high-risk early disease after chemotherapy. Our study describes tolerability and adverse effects, to understand continued applicability of the OlympiA trial analyses through comparison to available real-world data.Materials and methodsThis was a retrospective observational study using secondary real-world data for 47 patients who received olaparib between April 2023 and March 2024 from 11 NHS and HSC hospitals. Anonymised data was collected from electronic patient records for eligible patients. A standardised data collection tool was utilised capturing key metrics. Statistical analysis included descriptive statistics and comparisons of adverse events with the OlympiA trial using Chi-square or Fisher's exact tests (p < 0.05).ResultsThe research sample at baseline had broader age range including patients in their 60s, compared to the OlympiA patient population which lacked those aged over 49. It also has a more even distribution of BRCA1/BRCA2 mutations, higher rates of hormone receptor positive HER2-negative cancers and a greater use of neoadjuvant and platinum-based treatments. Adverse events were similar between the two populations. Fatigue was significantly more prevalent compared to OlympiA (p < 0.05). Nineteen patients had dose reductions due to adverse effects and four patients discontinued treatment early.ConclusionAdjuvant olaparib was well tolerated in our real-world UK population study, with toxicity profiles similar to the OlympiA trial. Fatigue was significantly more prevalent in the real-world cohort.