The EU and US show similar biosimilar distribution trends, with the EU having a broader portfolio. Biosimilars are most developed for inflammatory diseases, immunology, and oncology due to high costs and prevalence. The EMA leads in biosimilar approvals, but the FDA's approval rate is faster. Regulatory strategies and patent protections significantly impact biosimilar market access, with the EU benefiting earlier than the US. The FDA's Biosimilar Action Plan aims to improve biosimilar development, approval, and market competition.