Experience With Palbociclib in Metastatic Breast Cancer Patients Managed Under a Government Health Scheme at a Cancer Care Center in Southern India

Introduction According to Globocan 2022, breast cancer ranks number one among the cancers worldwide. South Asian women have a higher incidence compared to Westerners. Estrogen receptor (ER) and progesterone receptor (PR) positive tumors, termed hormonal receptor-positive tumors, account for most breast cancer presentations. In India, advanced-stage presentations are more common. In metastatic hormone receptor-positive breast cancer, hormonal therapy combined with cyclin-dependent kinase (CDK) 4/6 inhibitors is the standard treatment. Aim This study aimed to analyze the experience with generic palbociclib provided under the Government Health Scheme for metastatic hormone receptor-positive breast cancer at our institution. Methods This retrospective study was conducted on breast cancer patients admitted to a tertiary care center in South India. The data of ER and PR receptor-positive metastatic breast cancer patients who received palbociclib were identified and reviewed using medical records from 2023 to 2024. Results A total of 238 patients were analyzed, of which 41 received palbociclib for hormone receptor-positive metastatic breast cancer. The median age was 49 (33-75), with 53.5% (22) of women above 50. Denovo stage IV presentation was observed in 21 patients (51.2%), while progression to stage IV disease was noted in 11 patients (26.8%), and stages II and III were noted in nine patients (22%). Invasive ductal carcinoma was the most common histology. All patients were ER-positive, and 38 (92.7%) were PR-positive. About 17 patients (41.5%) had visceral metastasis, and 12 (29.3%) had bone-only metastasis. Local recurrence was seen in six patients (14.6%), and bone with visceral metastasis was seen in another six patients (14.6%). Progression within one year of hormonal therapy initiation was observed in 50% (10) of patients. Among 21 patients with upfront metastasis, nine were treated with prior chemotherapy. All patients were given 125 mg of oral palbociclib. Fatigue was the most common side effect in 34.1% (14), followed by myalgia in 21.9% (9), low hemoglobin levels of less than 8 g/dl in 14.6% (6), and nausea and vomiting in only 9.8% (4) of patients. Conclusion Hormone therapy combined with CDK4/6 inhibitors is the backbone of treatment for metastatic hormone-positive breast cancer. However, in developing countries like India, where most patients come from rural areas, using innovator palbociclib may not be feasible for many. With the availability of generic palbociclib under the Government Health Scheme, patients of metastatic hormone receptor-positive breast cancer will receive the protocol-based treatment.