Real-world feasibility of first-line palbociclib for hormone receptor-positive HER2-negative locally advanced/metastatic breast cancer in women aged 70 years and older – final results of the endocrine-sensitive cohort in the French prospective non-interventional PalomAGE study

BACKGROUND: Breast cancer (BC) is the most commonly diagnosed cancer among women, with 30% of cases occurring at age ≥70 years (70+). Because patients 70+ are underrepresented in BC clinical trials, real-world data may help fill treatment knowledge gaps for this population. PATIENTS AND METHODS: PalomAGE is a French observational, multicentre, prospective study assessing the real-world feasibility of ET + palbociclib in women 70+ with hormonal receptor-positive/HER2-negative (/HER+/HER2-) locally advanced/metastatic BC (ABC). The primary endpoint was palbociclib permanent discontinuation rate at 18 months. Secondary endpoints included time to treatment failure (TTF), real-world progression-free survival (rwPFS), health-related quality of life (HRQoL) and geriatric status (G8 and G-CODE). Here, we report results from the endocrine-sensitive cohort, using ET + palbociclib as first-line treatment. RESULTS: From October 2018 through December 2020, 412 patients were enrolled. Of these, 382 received ≥1 cycle of palbociclib. With a median follow-up of 25.2 months, the 18-month palbociclib permanent discontinuation rate was 41%. The median TTF and rwPFS were 23.0 and 30.4 months, respectively. Palbociclib dose reduction and permanent discontinuation due to adverse events occurred in 35% and 11% of patients, respectively. There were no new safety signals and HRQoL remained stable throughout treatment. An altered G8 (≤14/17) at baseline was an independent factor for palbociclib discontinuation by multivariate analysis. CONCLUSION: This analysis showed that first-line ET + palbociclib is feasible, well-tolerated and maintains HRQoL in women 70+ with endocrine-sensitive HR+/HER2- ABC, consistent with results from the general adult population. The G8 tool may help identify vulnerable older patients needing further geriatric assessment.