CT-P39 Shows Promise as a Cost-Saving Alternative to Omalizumab for CSU

Key Takeaways:

• CT-P39 is a biosimilar antibody of omalizumab and can be used to treat chronic spontaneous urticaria (CSU). It demonstrates similar rates of efficacy to reference omalizumab, and switching between drugs is not associated with any noteworthy change in effectiveness or safety.
• Patients treated with CT-P39 and reference omalizumab demonstrated comparable weekly itch severity scores, weekly hives severity scores, and weekly urticaria activity scores.
• Incidents of adverse events (AEs) were comparable between the 2 drugs, and most events were either grade 1 or 2 in intensity.

Omalizumab is a monoclonal antibody approved to treat patients with CSU, but its high cost limits patient access. Therefore, biosimilar antibodies such as CT-P39 are often offered as comparable cost-saving alternatives.

A randomized phase 3 clinical trial compared the efficacy and safety profile of CT-P39 with reference omalizumab. The study included 2 treatment periods and evaluated efficacy by measuring the changes in weekly itch severity score, weekly hives severity score, and weekly urticaria activity score.

The first treatment period included 619 patients: 204 patients were treated with CT-P39 300 mg, 205 patients were treated with reference omalizumab (ref-OMA) 300 mg, 107 patients were treated with CT-P39 150 mg, and 103 patients were treated with ref-OMA 150 mg. The second treatment period included 579 patients; in the ref-OMA 300 mg group, 97 patients continued using ref-OMA 300 mg, and 96 patients were switched to CT-P39 300 mg.

Comparable Efficacy and Safety Between Reference Omalizumab and CT-P39

Both CT-P39 300 mg and ref-OMA 300 mg had similar changes from baseline in weekly itch severity scores and weekly hives severity scores. The average of both scores decreased for all groups during the course of the trial.

The average weekly urticaria activity score was comparable between CT-P39 300 mg and ref-OMA 300 mg. At the end of the first treatment period, the score was slightly higher in patients treated with ref-OMA 300 mg. However, at the end of the second treatment period, the weekly urticaria activity score was higher in patients treated with CT-P39 300 mg.

Patients who switched from ref-OMA 300 mg to CT-P39 300 mg had no significant change in scores from patients who continued being treated with reference omalizumab. No notable differences were observed in efficacy between the 300 mg and 150 mg groups.

Rates of AEs were similar across all study cohorts. Most AEs were grade 1 or 2 events, with the most common AE being COVID-19. Less than 10% of patients experienced a drug-related AE.

According to the study’s authors, “Biosimilars can provide cost savings, potentially through increasing patient access to biologic therapies.”

The study’s findings show CT-P39 to be a promising omalizumab biosimilar that can be used as an alternative to treat patients with CSU.

Reference

Saini SS, Maurer M, Dytyatkovska Y, et al. CT-P39 compared with reference omalizumab in chronic spontaneous urticaria: results from a double-blind, randomized, active-controlled, phase 3 study. Allergy. 2025;80(8):2167-2177. doi:10.1111/all.16446