Introduction/Background Anemia is the featured hematological adverse effect associated with olaparib (a poly (ADP-ribose) polymerase (PARP) inhibitor). It was reported that anemia recovered after 18 months of treatment with olaparib, however the reason was unknown. We assessed the feature of anemia during treatment with olaparib.

Methodology We reviewed 10 patients with advanced ovarian cancer patients underwent maintenance monotherapy with olaparib in Gifu University Hospital between January 1, 2018, and April 30, 2019, retrospectively.

Results Although the mean hemoglobin levels decreased, it recovered after 16 weeks of treatment with olaparib. The maximum level of hemoglobin was 8.6±2.2 mg/dl at 16 weeks. Mean Corpuscular Volume (MCV) values gradually increased, it remained above the normal range during treatment. It was above 102.0±6.5 (range 102.0–112.2) fl after 12 weeks. Macrocytic anemia occurred during short-term treatment with olaparib and macrocytosis without anemia during long-term treatment.

Conclusion Olaparib lead to macrocytosis, however alternative mechanism would exists to recover anemia.

Disclosure Nothing to disclose.