Progression-free survival (PFS) and toxicities of palbociclib in a geriatric population

PurposeOver 40% of newly diagnosed metastatic breast cancer patients are 70 years old; however, this population is less likely to be represented in clinical trials. The objective of this study was to analyze PFS, dose reductions, dose delays, and toxicity in a geriatric population receiving palbociclib in a non-trial setting.MethodsPatients with metastatic breast cancer receiving palbociclib in any line of therapy were identified from a cohort of 845 patients at a large academic institution. Dose delays, dose reductions, and toxicities were retrospectively extracted from the medical record. Data were analyzed using Fischer's exact test for categorized variables and T test/Wilcoxon rank-sum test for continuous variables. PFS and OS were analyzed using the Kaplan-Meier method.Results605 patients who met eligibility criteria were included. 160 patients were 65 years old and 92 patients were 70 years old. Patients70 had a significantly increased number of dose reductions (p=0.03) and dose delays (p=0.02) compared to the younger patients. There was no significant increase in toxicities, including neutropenic fever, infections, or hospitalizations, in the 70 cohort (p=0.3). The 70 cohort had a significantly improved PFS as compared to the younger cohort (p=0.02); however, age was no longer a significant variable in the multivariate analysis.ConclusionsPalbociclib was well tolerated in the geriatric population and there was no difference in PFS between older and younger patients. These results are reassuring as palbociclib becomes the frontline standard of care therapy for patients.