Outcome with pertuzumab, docetaxel, and trastuzumab (PTH) regimen in patients with HER2 positive metastatic breast cancer: Real-world data from a single center in India.

Abstract

e13037 Background: Pertuzumab, Docetaxel and Trastuzumab (PTH) regimen constitutes one of the standard treatment regimens in human epidermal growth factor receptor-2 (HER2) positive metastatic breast cancer (MBC). The real-world outcomes of its use from the Indian sub-continent are lacking. Methods: We retrospectively reviewed the medical records of HER2-positive MBC treated with an upfront PTH regimen at the All India Institute of Medical Sciences, New Delhi, India, between Aug 2016 to July 2023. A total of six cycles of PTH [pertuzumab (840 mg loading followed by 420 mg), docetaxel (75 mg/m2), trastuzumab (8 mg/kg loading followed by 6 mg/kg) q21 days] were planned along with granulocyte-colony stimulating factor (GCSF) prophylaxis. Patients were continued on maintenance trastuzumab after 6 cycles (till disease progression) and hormonal agent if indicated. The primary outcome was progression-free survival (PFS). The secondary outcome was overall survival (OS), overall response rate (ORR) rates, and toxicity. Results: Eighty-seven were included with a median age of 48 years (range, 25-73). Overall, 38 (43.6%) patients had hormone-positive (estrogen receptor and or progesterone receptor) disease and 48 (55.17%) were premenopausal. Thirty-five (40.2%) patients had received prior adjuvant and neoadjuvant treatment. Eighty patients (91.5%) had visceral metastasis and the most common site was the liver followed by the lung. After a median follow-up of 36 months, the median PFS was 15 months and OS was 42 months. The ORR was 85.3% and complete response (CR) was observed in 14(16.09%) patients. The survival outcomes were significantly better among those with hormone-negative disease and among those who achieved CR after 6 cycles of PTH. Grade 3/4 toxicity was seen in 12% of patients which led to dose modification, interruption, and change in chemotherapy. Two patients developed reversible left asymptomatic ventricular systolic dysfunction. None of the patients developed congestive heart failure. The most common grade 3/4 toxicities were diarrhea in 8 (9.1%) patients, cutaneous rash in 2 (2.2%) patients and thrombocytopenia in 2 (2.2%) patients. There were two cases of febrile neutropenia. Conclusions: In a real-world context, PTH is an effective and well-tolerated regimen for in patients with HER2-positive MBC in India. Hormone-positive disease has poor survival compared with hormone negative disease.