Comparing relative dose intensity of weekly nab-paclitaxel regimens in early breast cancer: A retrospective study at a large academic outpatient cancer center

IntroductionNational guidelines for breast cancer support substitution with nab-paclitaxel for paclitaxel or docetaxel due to medical necessity.¹ This study aimed to assess for correlation between weekly nab-paclitaxel dose and relative dose intensity (RDI) amongst early breast cancer patients.MethodsThis single-center, retrospective cohort study included adult patients with early breast cancer who switched from weekly paclitaxel to nab-paclitaxel after hypersensitivity reaction. The primary outcome of RDI was assessed in patients receiving nab-paclitaxel 80 mg/m² (NB80) or 100 mg/m² (NB100) intravenously (IV) weekly. Secondary outcomes included adverse effects, incidence of nab-paclitaxel alterations, and growth factor (GCSF) administration for secondary prophylaxis.ResultsAmongst 26 patients, the median age was 43 years (range 33 to 71), with the majority (54%) having stage II or later disease. Median RDI with NB80 was 91% (range 69 to 100%) versus 86% (55 to 100%) with NB100. Fifty percent of all patients underwent dose reductions. Dose delays occurred in a higher proportion of patients on 50% with NB80 vs 33% with NB100. Early nab-paclitaxel discontinuations occurred more on NB100 (33% vs 10%). Incidence of chemotherapy-induced peripheral neuropathy (CIPN) was 80% vs 83% with NB80 and NB100, respectively, while grade 2 CIPN was more common on NB100 (50% vs 35%). A lower rate of neutropenia resulted from NB80 (60 vs 67% with NB100).ConclusionNab-paclitaxel dosed at 80 mg/m² IV weekly, after switching due to paclitaxel hypersensitivity, may promote improved RDI and safety compared to nab-paclitaxel 100 mg/m² weekly amongst early breast cancer patients.