Scope
This page provides information on omalizumab biosimilars from the point of UK marketing authorisation onwards. It includes details on licensed indications, available formulations, evidence supporting bioequivalence and practical considerations relevant to clinical use.
As of January 2026, Omlyclo (Celltrion) is the only omalizumab biosimilar product with UK marketing authorisation. See our Preparing to use omalizumab biosimilar (SPS page) article for details of additional biosimilars in development.
This page will be updated as further biosimilars progress through the regulatory and market entry process.
NHS Framework awards
NHS Trusts should be guided in choice of biosimilar products by NHS Framework awards.
The national omalizumab contract is in place from 1st February 2026 to 31st September 2027.
Further detail should be obtained from the relevant Regional Pharmacy Procurement Specialist team.
Licensed indications
Omlyclo (Celltrion) is licensed for the same indications as the reference product Xolair (Novartis). Refer to the individual summary of medicinal product characteristics (SmPC) for further information.
Note: the 75mg strength preparation (Xolair and Omlyclo) is not licensed for chronic spontaneous urticaria (CSU).
Licensed preparations
Omlyclo (Celltrion) is available as both pre-filled syringes and pre-filled pens in 150mg and 75mg strengths.
A 300mg strength may become available later in 2026.
Evidence supporting safety and efficacy
The clinical efficacy, safety profile and immunogenicity of Omlyclo are comparable to those of the reference product Xolair.
Efficacy data
In a randomised, double-blind, active controlled parallel group study, 409 patients aged between 12 and 75 years with chronic spontaneous urticaria (CSU) not responding to antihistamine treatment received Omlyclo (biosimilar omalizumab, CT-P39) or the reference product (Xolair). The study demonstrated similarity in clinical efficacy after 12 weeks of treatment. The weekly itch severity score (ISS7) was reduced by an average of 9.21 points in people who received Omlyclo compared with an average of 9.98 points in those who received Xolair [95% CI, -0.37, 1.90] which was within the predefined equivalence margin of [-2.0, 2.0].
For further details see the published abstract or the European Public Assessment Report.
Extrapolation of data to other indications
Omlyclo is considered highly similar to the reference product (Xolair) based on results of the clinical trial in patients with CSU. Its licence is extrapolated to the additional indications already approved (licensed) for the reference product (Xolair). Thus, avoiding unnecessary repetition of clinical trials.
The CSU population was chosen for the biosimilar efficacy study in preference to that with allergic asthma. Patients with CSU were considered a more homogenous population and therefore more sensitive to any potential differences between products.
See understanding biological and biosimilar medicines (SPS page) for further information regarding the regulatory process for biosimilar medicines.
Pharmacokinetic trial data
In a published randomised, double-blind, two-part, single-dose, pharmacokinetic study 146 healthy adults received 150mg Omlyclo or Xolair. The study demonstrated primary outcomes of pharmacokinetic parameters within pre-specified equivalence margins. Safety and immunogenicity were comparable between products.
Differences between brands
This section outlines key pharmaceutical and practical differences between Omlyclo and the reference product Xolair.
Administration
The first three doses of omalizumab must be administered by or under the supervision of a healthcare professional. For those with no known history of anaphylaxis, patients or caregivers can administer omalizumab (Xolair, or Omlyclo) from the fourth dose onwards. Appropriate training should be provided.
The requirement to give the first three doses under supervision is molecule-specific, not brand specific. Therefore, providing the patient is deemed suitable for unsupervised administration and is appropriately trained on the new device:
- those stable self-administering Xolair can switch to self-administration of Omlyclo
- those stable receiving carer-administered Xolair can switch to carer-administration of Omlyclo
The administration instructions for Omlyclo are consistent with those for the equivalent Xolair device. However, device and packaging colouring differs between brands and strengths and may require additional attention during selection and administration. Full details are provided in the patient information leaflets.
Packaging and associated risks
To minimise errors, consider processes to avoid inadvertent switching between omalizumab originator and biosimilar.
Omlyclo
Be aware of differences in packaging colour that could cause confusion.
- Xolair: blue identifies the 75mg strength
- Omlyclo: blue to identifies the 150mg strength
Clear processes should be in place to avoid mis-selection, especially if both products are available during a transition period
Excipients
There are no differences between the excipients listed in the reference product (Xolair) and the biosimilar (Omlyclo).
The Omlyclo SmPC expresses the L-isomer forms of several excipients, for example L-histidine. L-histidine is a synonym for histidine; the terms can be used interchangeably.
Presence of latex
Differences do exist between omalizumab products
Xolair pre-filled syringes
The removable needle cap may contain dry rubber (latex) and should not be handled by anyone who is sensitive to latex. Use in latex-sensitive individuals has not been studied, therefore risk of a hypersensitivity reaction cannot be ruled out.
Xolair pre-filled pens
No components contain natural rubber latex (confirmed by Novartis).
Omlyclo (all presentations)
The needle cap of the pre-filled syringes and pens is made of synthetic materials (elastomer and polypropylene). No components contain natural rubber latex
Storage and stability
Comparisons of storage and in use stability between omalizumab biosimilars and the reference product (Xolair):
Omlyclo
Store in a refrigerator (2 °C to 8 °C).
The product may be kept for a total of 7 days at room temperature (25 °C)
Xolair
Store in a refrigerator (2 °C to 8 °C).
The product may be kept for a total of 48 hours at room temperature (25 °C)
Further resources
SPS have further resources on biosimilars and biosimilar omalizumab.
Preparing to use omalizumab biosimilar
Understanding biological and biosimilar medicines
Understanding biosimilar and generic market entry
Update history
- NHS Framework is due to start in February, Omlyco has been awarded and is available. Consistency in administration instructions added, including links to patient information leaflets.
- Additional clarification regarding administration requirements when switching brands. The requirement for the first-three doses to be administered under the supervision of a health care professional is molecule-specific rather than brand-specific.
- Republished
- Published