Food and Drug Administration regulation of biosimilar products: Improving affordability of biologics for patients with asthma and allergic diseases.

On March 7, 2025, the US Food and Drug Administration (FDA) approved the first biosimilar to omalizumab (omalizumab-igec, Omlyclo; Celltrion). This is the first biosimilar approved for a biologic with an indication for the treatment of allergic diseases and/or asthma. Recent FDA announcements focus on accelerating biosimilar development and lowering costs by streamlining the approval process. On October 29, 2025, the FDA issued draft guidance proposing to no longer routinely require comparative clinical efficacy studies for biosimilarity, supporting the goal of reducing development time and cost. This review discusses FDA regulation of biologics and biosimilars, the recent approval of the first omalizumab biosimilar, and the evolving regulatory landscape for biosimilars to decrease the costs of their development while ensuring their efficacy and safety. The approval of biosimilars for treating allergic diseases and asthma is expected to significantly improve accessibility and affordability of these therapies, providing health care providers and patients with confidence in high-quality, cost-effective treatment options for patients with severe and refractory asthma and allergic conditions.