Age Is a Risk Factor for Olaparib Dose Modification and Discontinuation in Patients With Ovarian Cancer

Olaparib, a poly (ADP-ribose) polymerase inhibitor, is widely used as maintenance therapy for ovarian cancer. Dose modification, such as dose reduction and treatment interruption, are frequently performed to manage adverse events (AEs) of olaparib. By identifying patients at high risk for dose modification before administration, interventions related to appropriate control of AEs can be implemented. This study aimed to evaluate risk factors of olaparib dose modification and its clinical usefulness. Sixty patients with ovarian cancer who received olaparib were included in this retrospective cohort study. Associations between patients' characteristics and dose modification were evaluated by multivariate logistic regression analysis. We also examined whether risk factors of dose modification were associated with treatment discontinuation due to AEs. Twenty-five (41.7%) patients required dose modification. Patients who required dose modification were significantly older (p=0.018) and tended to be more underweight (p=0.078) than those who did not require dose modification. In multivariate analysis, increasing age was significantly associated with dose modification (odds ratio=1.056; 95% confidence interval=1.002-1.112; p=0.034). The optimal cutoff of age as a risk factor for dose modification, calculated from receiver operating characteristic curves, was 65.0 years. Patients aged 65.0 years and older were significantly more likely to discontinue olaparib owing to AEs (p=0.0437). Age is a risk factor of olaparib dose modification due to AEs. Older patients, who frequently require dose modification, are more likely to discontinue olaparib, suggesting that strict management of AEs is particularly necessary in this patient group.