Dose reduction of olaparib in older patients: Insights from an analysis of a National Database in Japan.

AIM: Although the advent of a poly polymerase inhibitors has greatly advanced the tailoring of cancer treatment, there is a dearth of real-world evidence on the actual use of olaparib in aging populations, especially those using national-level data. METHODS: We extracted and analyzed all prescriptions of olaparib in female outpatients from the National Database Open Data Japan (NDB Open Data) from April 2019 to March 2021. The recommended standard dose of olaparib is four tablets of the 150 mg formulation per day, while the 100 mg formulation of olaparib can be considered as an alternative dose in the occurrence of hematologic toxicity. We calculated the proportion of 100 mg compared to the 150 mg prescriptions across age groups. A Cochrane-Armitage trend test was used to examine the association of age groups with the proportion of 100 mg prescriptions. RESULTS: The total number of prescriptions of the 100 mg formulation and the 150 mg formulation were 1449 222, and 4233 625, respectively. Overall, 45.1% (2567 513/5682 847 prescriptions) of olaparib were prescribed for patients 65 years of age or older in females. Stratified by age group, the proportion of 100 mg compared to the 150 mg prescriptions significantly increased with age (p < 0.0001). CONCLUSIONS: Given that the 100 mg formulation of olaparib can be considered as an alternative dose in Japan in the occurrence of hematologic toxicity, our observations indicate the dose reduction of olaparib in older patients in Japan. Further investigations are necessary to assess its efficacy and safety at a reduced dose.