Abstract P1-18-04: Feasibility of palbociclib in women aged 70 and older with resistant and/or pretreated advanced breast cancer in the PALOMAGE study

Abstract

Abstract Background:In France, more than 1 in 3 women diagnosed with breast cancer (BC) is 70 years old or older. Given the many factors that may impact on the success of treatment in these older patients, especially with advanced BC (ABC), treatment feasibility (i.e. receiving the optimal duration of treatment) should be assessed carefully in real life. Methods:PALOMAGE is a French prospective study evaluating palbociclib (PAL) + endocrine therapy (ET) in real life setting in women aged ≥70 with hormone receptors positive (HR+) HER2- ABC, either ET-sensitive with no prior systemic treatment for ABC (cohort A), or ET-resistant (relapse during or < 1 year after the end of adjuvant ET) and/or with prior systemic treatment for ABC (cohort B). Quality of life data (EORTC QLQ-C30 and ELD14) and geriatric data [G8 and Geriatric-COre DatasEt (G-CODE)] were collected. This analysis in cohort B reports on the primary endpoint: treatment feasibility based on the rate of permanent PAL discontinuation at 6 months (mo) for any reason including progression, toxicity, patient’s choice, or death. Two-sided 95% binomial confidence interval (CI) was used. Results:From 10/2018 to 07/2020, 406 patients were included in cohort B: median age 78 years (69-98) (15.8% > 85), 15.8% ECOG performance status (PS) ≥2, 67.8% G8 score ≤14, 86.7% Charlson score ≥4, 49.3% visceral metastasis (liver 25.9%, lung 27.6%), 24.4% ≥2 lines of systemic treatment for ABC, 52.4% prior chemotherapy. PAL starting dose was 125, 100 and 75 mg in 72.6%, 22.1% and 5.2% of patients, respectively, combined with fulvestrant or an aromatase inhibitor in 65.3% and 34.7%, respectively.The primary endpoint analysis was performed on the full analysis set of cohort B: amongst 378 patients, 109 (28.8%; 95%CI=24.3-33.7) had a permanent PAL discontinuation at 6 mo due to progression (67 patients/17.7%), toxicity (14 patients/3.7%), death (14 patients/3.7%), or patient’s choice (11 patients/2.9%). Visceral progression was observed in 32 patients (8.5%), mainly in liver. Neutropenia (including 1 febrile neutropenia) was the main toxicity leading to PAL discontinuation. No death was considered PAL-related by investigators. Treatment discontinuation rate at 6 mo according to PAL starting dose 125/100/75 mg was 28% (95%CI=22.7-33.6), 30.5% (95%CI=20.8-41.6), and 35.3% (95%CI=14.2-61.7), respectively. With a median follow-up of 11.3 mo, 33.6% of patients were still on PAL treatment. Median time to treatment failure (TTF) was 11.6 mo (95%CI=10-13). Efficacy, safety and quality of life will be presented according to geriatric status. Conclusion:PALOMAGE is a unique French real-world study dedicated to older patients treated with PAL for ABC. In this cohort B analysis, treatment discontinuation rate at 6 mo was 28.8%, close to what has been observed in PALOMA 3 study, and did not differ according to PAL starting dose. Although not controlled, these data are reassuring and suggest that PAL treatment is feasible in resistant and/or pretreated women aged ≥70. Citation Format: Etienne Brain, Marina Pulido, Elena Paillaud, Jessica Grosjean, William Mina, Philippe Caillet, Louis Tassy, Pierre Soubeyran, Fanny Bouteiller, Nada Rifi, Jean-Michel Vauthier, Claire Falandry, Elisabeth Carola. Feasibility of palbociclib in women aged 70 and older with resistant and/or pretreated advanced breast cancer in the PALOMAGE study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-18-04.