Prescribing preferences for hormone sensitive (HR+) metastatic breast cancer (mBC) in the CDK 4/6 inhibitor (CDK 4/6i) era.

Abstract

e13058 Background: CDK 4/6i is a category 1 guideline-recommended therapy for HR+/HER2- mBC in both first-line (1L) with an aromatase inhibitor and second-line (2L) with fulvestrant and without prior CDK 4/6i. We sought to understand community oncologists’ (c-oncs) prescribing preferences and sequencing for 1L, 2L, and third-line (3L) HR+/HER2- mBC patients across several common clinical scenarios (CS). Methods: C-oncs were presented 4 hypothetical HR+/HER2- mBC clinical scenarios (CS 1-4) via web-based survey. CS differed by menopausal status, prior adjuvant therapy and nature of metastases (mets) (i.e., bulky liver, lung, bone), but otherwise uniform: asymptomatic presentation, PI3K negative, identical response extent and duration in 1L, 2L, and 3L. Treatment preferences: hormonal (H), single agent (SA) or combination chemotherapy (CC) for 1L, 2L, and 3L in each CS were queried. We describe these preference patterns. Results: 47 U.S. c-oncs participated: mean years in practice was 22.7 and mean mBC patients under active treatment was 23.3. Preference for treatment and sequence, regardless of CS, per LOT were: 1L = 71% H, 14% SA, 16% CC; 2L = 51% H, 31% SA, 16% CC; and 3L = 35% H, 59% SA, 6% CC (Table). Of the 71% who preferred 1L H, the CDK4/6i % were: 73% overall, 58% when mets described as bulky liver, 94% when described as bone and or lung. The preference for pre-planned sequential chemo-hormonal therapy in 1L resulted in 63% of initial chemotherapy followed immediately by H; of which CDK 4/6i was preferred in 47%. In total, the initial and post-chemo CDK4/6i 1L preference was 80%. 2L hormonal preferences by frequency were: everolimus + exemestane = 38%, CDK 4/6i + fulvestrant = 20%, fulvestrant = 19%. SA preferences: 2L = capecitabine 46%, taxane 25%; 3L = capecitabine 40%, eribulin 32%. CC preferences included atezolizumab + nab-paclitaxel 24% in 1L and 16% in 2L. Conclusions: 1L HR+/HER2- mBC treatment is highly variable and preferences that warrant further research include: the role of CC, specifically atezolizumab + nab-paclitaxel; repeated CDK4/6i line of therapy; H therapy post CDK4/6i progression; and optimal SA sequencing. [Table: see text]