The global oncology biosimilars market is projected to grow from USD 12.81 billion in 2026 to USD 24.96 billion by 2031, after reaching USD 11.22 billion in 2025, for a 14.25% compound annual growth rate, according to ResearchAndMarkets. The report links the expansion to expiring patents on major oncology biologics, payer efforts to reduce treatment costs, rising cancer incidence and broader hospital adoption of biosimilar purchasing contracts. Breast cancer accounted for 28.15% of the market in 2025 and monoclonal antibodies made up 68.54%, led by trastuzumab, bevacizumab and rituximab biosimilars. Lung cancer is forecast to be the fastest-growing indication through 2031 at a 16.75% CAGR, while other drug classes including checkpoint inhibitor and VEGF-related therapies are projected to expand at an 18.16% CAGR. North America held 36.18% of the market in 2025, with reported U.S. hospital biosimilar utilization reaching 93% for bevacizumab, 87% for trastuzumab and 84% for rituximab by 2024, while Asia-Pacific is expected to post the fastest regional growth at 18.05%. The report also points to June 2026 trial progress for Samsung Bioepis' SB27 and the European Commission's April 2026 approval of POHERDY, the first pertuzumab biosimilar approved in Europe, as signs of continued portfolio expansion, even as prescriber caution over immunogenicity, switching and interchangeability remains a restraint.