Background: Biosimilars have the potential for cost savings and thus help increase access to treatment. The first trastuzumab biosimilar was introduced in 2014 in India. A qualitative study was conducted focusing on understanding the physicians’ perceptions on using trastuzumab biosimilars in HER2+ breast cancer (BC) and changes in trends from pre-biosimilar to post-biosimilar era in India. These study results were presented at ESMO Asia 2022 conference (https://www.annalsofoncology.org/article/S0923-7534(22)04219-3/fulltext). The current abstract utilizes sales data on trastuzumab to reexamine trends in biosimilar usage in this indication in India. Methods: Trends in patients treated with trastuzumab innovator or biosimilar were identified using data from Ipsos’ India Oncology Sales Audit (Jan 2014-Dec 2020), which reports Net Realized Value of all brands marketed by ~60 oncology companies across India. Data were collected using open-source intelligence and telephone interviews with sales/marketing personnel from pharmaceutical companies and distributors. The number of patients treated with trastuzumab was calculated using Microsoft Excel based on their body weight (assumed to be 60 kg), completing 6 months (9 cycles) of therapy and consuming 1 vial of 440 mg/cycle (8 mg/kg loading dose and 6mg/kg maintenance dose Q3W). Results: Approximately 68,000 HER2+ BC patients received trastuzumab from 2014-2020, out of which 46,000 received biosimilars and 22,000 innovators. Eighteen percent of patients were treated with biosimilars in 2014 which increased to 88% by end of 2020. There was a 17% decline in patients treated with innovator from the year 2017-2018, whereas patients treated with biosimilars grew by 229% in the same period, due to the launch of multiple biosimilars in this era. In the year 2020, there was a 15% decline (13% for biosimilar vs 30% for innovator) in the overall number of patients receiving trastuzumab which was primarily due to the impact of COVID-19. Similarly, pertuzumab usage increased 17 times from its introduction in 2015 till 2020. There has been decline in innovator trastuzumab patients and increase in the number of patients treated with biosimilar trastuzumab and pertuzumab in the last seven years; supporting our physician perception survey, wherein oncologists used pertuzumab with biosimilars in almost 45% of their patients. Conclusions: Findings from this data coincide with the physician perception survey suggesting increasing trend in usage of biosimilars in the last seven years. Biosimilars are preferred option amongst oncologists in India because of affordability and accessibility. The availability of quality biosimilars has the potential to reduce health care expenditure, and an effective supply also increase patient’s adherence to treatment.