Omlyclo, First Interchangeable Xolair Biosimilar, Launches in the US

Celltrion USA announced on October 5, 2026, that Omlyclo (omalizumab-igec), the first FDA-approved interchangeable biosimilar to Xolair (omalizumab), is commercially available in the United States. The launch adds an omalizumab option for patients with chronic spontaneous urticaria (CSU) and other approved allergic and inflammatory conditions.

The company is offering single-dose prefilled syringes in 75 mg/0.5 mL, 150 mg/mL, and 300 mg/2 mL presentations for subcutaneous administration. In addition to CSU, Omlyclo is approved for certain patients with asthma, chronic rhinosinusitis with nasal polyps, and IgE-mediated food allergy.¹

The commercial announcement follows Omlyclo’s initial FDA approval in March 2025. In its announcement of that approval, the FDA identified Omlyclo as the first interchangeable biosimilar to Xolair and described its mechanism as binding to IgE and preventing its interaction with IgE receptors.⁴

Relevance to CSU Care

For dermatology clinicians, the CSU indication covers adults and adolescents aged 12 years and older who remain symptomatic despite H1 antihistamine treatment. Omlyclo is not indicated for other forms of urticaria.

The recommended CSU dosage is 150 mg or 300 mg administered subcutaneously every 4 weeks. Unlike dosing for several of its other indications, CSU dosing does not depend on serum IgE levels or body weight. The 300 mg dose may be given using one 300 mg/2 mL injection or two 150 mg/mL injections.⁴

Understanding Interchangeability

The FDA explains that biosimilars must be highly similar to their reference biologic and have no clinically meaningful differences. An interchangeable designation permits pharmacy-level substitution without consulting the prescriber, subject to state pharmacy laws. Both biosimilars and interchangeable biosimilars meet the FDA’s standards for safety and effectiveness.

This distinction is relevant when discussing a potential change from Xolair to Omlyclo with patients. Interchangeability concerns substitution; it does not establish superior efficacy or safety over the reference product.⁴

Celltrion positioned the launch as an opportunity to improve access and affordability. However, the announcement did not provide a launch price or quantify patient savings. The FDA notes that potential savings and insurance coverage should be assessed with the patient’s pharmacy and insurer.¹

Safety and Administration

Omlyclo carries a boxed warning for anaphylaxis, which can occur after the first dose or more than a year after treatment begins. Therapy should be initiated in a health care setting equipped to manage anaphylaxis, with appropriate observation after administration. Self-administration requires a clinician’s assessment of patient eligibility and risk mitigation.²

For practices treating CSU, the launch provides an additional product option within established anti-IgE therapy. Applying that option requires attention to the approved indication, administration precautions, and the patient’s coverage.

References

1. Celltrion. (2026, October 5). Omlyclo (omalizumab-igec), the first and only FDA-approved interchangeable biosimilar to Xolair, now commercially available in the U.S.PR Newswire.
2. US Food and Drug Administration. (2025, March 11). FDA roundup: March 11, 2025.
3. Celltrion. (2026). Omlyclo (omalizumab-igec) injection: Prescribing information.
4. US Food and Drug Administration. (n.d.). Biosimilar and interchangeable biologics: More treatment choices.