Omalizumab Biosimilar CT-P39: Quality of Life Gains Precede CSU Control

Quality of life gains came before disease activity responses with omalizumab in chronic spontaneous urticaria (CSU), according to post hoc analyses of the omalizumab-igec (Omlyclo; CT-P39) phase 3 trial Celltrion USA will present at the American College of Allergy, Asthma and Immunology (ACAAI) 2026 Annual Scientific Meeting in Phoenix.

“The impact on quality of life can be substantial, with approximately 40% of patients with CSU scoring greater than 10 on the Dermatology Life Quality Index,” said Juby Jacob-Nara, MD, senior vice president and chief medical officer at Celltrion USA, in a statement.1 All 3 analyses will be presented as ePosters during Meet the Author sessions at the Phoenix Convention Center on November 14 and 15.¹

Additional analyses found comparable efficacy between CT-P39 and reference omalizumab (Xolair) regardless of baseline itch severity, and comparable pharmacokinetics in patients with comorbid asthma.¹ The data follow the October 5, 2026, US commercial launch of omalizumab-igec, which the FDA approved in March 2025 as interchangeable with reference omalizumab across all 4 of its indications.¹,2 Approval was based on a double-blind, randomized, active-controlled phase 3 trial of 619 patients with CSU, which showed equivalent efficacy between CT-P39 and reference omalizumab on change in Weekly Itch Severity Score (ISS7) at week 12.3

Omalizumab Disease Activity and Quality of Life in CSU

Metz and colleagues assessed patients with CSU receiving omalizumab 300 mg every 4 weeks for 24 weeks, followed by a 16-week off-treatment period.¹ Investigators sorted disease activity, measured by the Weekly Urticaria Activity Score (UAS7), and quality of life, measured by the Dermatology Life Quality Index (DLQI), into 5 previously established categories each to track how patients moved between categories across the study.¹ At baseline, the largest share of patients (36.7%) had severe disease and reported a very large effect of CSU on quality of life.¹

By week 12, 43.9% of patients were in the well-controlled or complete response UAS7 categories, and 72.5% reported no or small effect of CSU on quality of life.¹ At week 24, the end of treatment, 44.4% of patients achieved a complete response with no effect of CSU on quality of life.¹

At week 40, 16 weeks after the final dose, 41.7% of patients remained in the well-controlled or complete response categories with no or small effect on quality of life.¹ According to the investigators, quality of life improvements emerged earlier than disease activity improvements, and the week 40 data suggest persistent treatment effects up to 16 weeks after omalizumab discontinuation.¹

CT-P39 Efficacy by Itch Severity and Pharmacokinetics in Comorbid Asthma

A second analysis, from Zuberbier and colleagues, grouped 409 patients receiving CT-P39 or reference omalizumab 300 mg every 4 weeks by baseline ISS7: ISS7 ≥13 (n = 331) or ISS7 <13 (n = 78).¹ UAS7 and Chronic Urticaria Quality of Life Questionnaire (CU-Q2oL) scores declined at weeks 12, 24, and 40 regardless of baseline itch severity, with outcomes analyzed descriptively.¹ At week 24, mean UAS7 reductions were –24.8 with CT-P39 vs –26.3 with reference omalizumab in the ISS7 ≥13 group and –15.7 vs –16.0 in the ISS7 <13 group.¹

Pharmacokinetics With CT-P39 vs Reference Omalizumab

The third analysis, from Heffler and colleagues, evaluated pharmacokinetics and target engagement in 41 patients with physician-reported asthma at baseline who received CT-P39 or reference omalizumab 150 mg or 300 mg every 4 weeks.¹

At week 12, mean serum omalizumab concentrations were 26.9 vs 21.5 µg/mL with CT-P39 and reference omalizumab at 300 mg, and 15.2 vs 13.1 µg/mL at 150 mg.¹ Free immunoglobulin E (IgE) levels were 4.2 vs 2.7 ng/mL at 300 mg and 6.1 vs 2.9 ng/mL at 150 mg, respectively.¹ Investigators concluded CT-P39 demonstrated comparable pharmacokinetics and similar target engagement to reference omalizumab in this subgroup.¹

The ACAAI analyses did not report new safety data. Omalizumab-igec carries a boxed warning for anaphylaxis, and its label directs clinicians to start therapy in a healthcare setting and observe patients after administration.¹

References

1. Celltrion USA. Celltrion to present new analyses of OMLYCLO (omalizumab-igec) in chronic spontaneous urticaria at ACAAI 2026. Published November 12, 2026. Accessed November 12, 2026.

2. Celltrion USA. OMLYCLO (omalizumab-igec), the first and only FDA-approved interchangeable biosimilar to XOLAIR, now commercially available in the U.S. Published October 5, 2026. Accessed November 12, 2026. https://www.prnewswire.com/news-releases/omlyclo-omalizumab-igec-the-first-and-only-fda-approved-interchangeable-biosimilar-to-xolair-now-commercially-available-in-the-us-302898400.html

3. 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