Efficacy and safety of palbociclib in treatment of HR-positive advanced breast cancer patients: A single center real-world experience.

Abstract

e13035 Background: With an estimated 2.3 million new cases (11.7% of all cases), female breast cancer is the leading cause of cancer globally as of 2020. Metastatic or advanced breast cancer is an incurable disease with a 5-year overall survival rate of 28.1%. Palbociclib, a cyclin-dependent kinase 4/6 inhibitor combined with an aromatase inhibitor, is approved to treat HR+/HER2- metastatic breast cancer (MBC). The present single-arm study evaluates the real world experience of efficacy and safety of Palbociclib-Letrozole for the treatment of HR+/HER2- MBC in the Indian population. Methods: MBC patients with or without prior chemotherapy and hormone therapy were treated with Palbociclib 125 mg once daily (3/1 schedule) plus Letrozole 2.5 mg once daily. The efficacy was recorded as objective response or disease control rate based on the response as per the RECIST criteria. The study also reports the incidence and severity of adverse events during the treatment duration. The tolerability was assessed per Common Terminology Criteria for Adverse Events (CTCAE) v.4.0 and coded using Medical Dictionary for Regulatory Activities (MedDRA) v.21.0. Results: A total of 102 patients were treated from 2017 to 2020 at the tertiary cancer center. The efficacy response is captured as per the investigator's assessment of the disease response. The response is as captured for 100/102 patients (two patients lost to follow-up) and are represented in Table. About 17% (23/100) patients achieved an objective response, while 54% (57/100) showed disease control. The tolerability was assessed as treatment-related side-effects (adverse events (AEs) and severe adverse events (SAEs)) as reported by the treating oncologist. Overall, 61 adverse events were observed in 40/102 (39.22%). The most-reported AE, neutropenia, was reported in 13 patients, followed by chest pain and breathlessness. Conclusions: In the present study, Palbociclib + Letrozole reported good clinical response at the end of treatment duration with a manageable tolerability profile in the Indian population.