Analysis of Clinical Factors in Olaparib-related Anemia Using Adverse Drug Event Reporting Databases

Anemia is one of the dose-limiting toxicities of olaparib. A global randomized controlled trial confirmed that anemia occurrence in Japanese was relatively high. The factors related to anemia in different nationalities remain unknown. Therefore, this study investigated the factors of olaparib-related anemia in real-world settings using an adverse event reporting system database.We used data from FDA Adverse Events Reporting System (FAERS) and Japanese Adverse Drug Event Report database (JADER) between 2018 and 2021. FAERS reports from Japan were collected to conduct subgroup analysis, which was defined as FAERS-Japan. The endpoint was the occurrence of olaparib-related anemia. Disproportionality analysis was conducted to calculate reporting odds ratio (ROR), with a confidence interval of 95%. Adjusted ROR (aROR) was calculated to control for sex differences.In FAERS and JADER, the daily olaparib dose per body weight (DPBW) ≥12 mg/kg was associated with anemia occurrence [aROR; FAERS, 4.483 (3.009-6.680), p<0.001, FAERS-Japan, 1.834 (1.091-3.063), p=0.009, and JADER, 1.628 (1.039-2.551), p=0.034]. Furthermore, FAERS reports confirmed that females with body weight <50 kg, reports from Japan, concomitant use of drugs causing vitamin B12 deficiency, and previous platinum treatment history were associated with olaparib-related anemia. FAERS-Japan also showed that body weight <50 kg and previous platinum treatment history were associated with anemia occurrence.High DPBW constitutes a significant risk of olaparib-related anemia. In addition, information on co-administration of drugs causing vitamin B12 deficiency and previous platinum treatment history is also important for the evaluation of the risk of olaparib-related anemia.