Yuhan's Lesigercept Shows Promise in Phase 1b Trial, Demonstrating Superior IgE Suppression in High-Risk Patients

Yuhan Corporation's Lesigercept showed strong and sustained suppression of 'free IgE' in a Phase 1b trial, particularly outperforming Omalizumab in patients with high IgE levels.

This result is significant as it suggests a clear point of differentiation in a market where competitors have failed to prove superiority over the existing standard of care, Omalizumab.

The positive data strengthens confidence in the ongoing Phase 2 trial (CLEAR), which is designed to validate Lesigercept's efficacy in patients who do not respond to current treatments.

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Yuhan Corporation has unveiled promising results from its Phase 1b study of Lesigercept, a next-generation treatment for severe allergic diseases.

The core of the news lies in Lesigercept's ability to potently and persistently suppress 'free IgE', the key molecule driving allergic reactions. In a recent trial, the drug showed excellent safety and a clear dose-dependent effect. Most impressively, in patients with high baseline IgE levels—a difficult-to-treat group—Lesigercept maintained very low free IgE levels for a median of 15 days, while both the placebo and the current standard, Omalizumab, showed no such lasting effect.

This finding is particularly significant because of the high bar in the allergy treatment market. First, the market leader, Omalizumab (Xolair), is well-established, and its recent FDA approval for food allergies has further validated the anti-IgE approach. Second, another next-generation drug, Novartis's Ligelizumab, failed in 2021 to prove superiority over Omalizumab in a large Phase 3 trial. This created a clear challenge for newcomers: they must be significantly better, not just comparable. Lesigercept's unique design as a high-affinity 'IgE trap' and its strong performance in high-IgE patients provide a compelling mechanical argument for how it could clear this high hurdle.

These encouraging results are not happening in a vacuum; they directly support the ongoing global Phase 2 clinical trial, known as the CLEAR study. This trial is strategically designed to include patients with chronic spontaneous urticaria (CSU) who have not responded to antihistamines and may have even failed Omalizumab therapy. The consistent safety and potent IgE suppression seen in the Phase 1b study build confidence that Lesigercept can deliver meaningful clinical benefits for these underserved patients.

In essence, the latest data does more than just confirm the drug's safety. It provides a concrete signal of mechanistic superiority, especially for the most challenging patient populations. By demonstrating a stronger and longer-lasting effect on the biological driver of the disease, Yuhan has increased the perceived probability of success for its pivotal Phase 2 study and strengthened its case for future partnerships.

Glossary
IgE (Immunoglobulin E): An antibody produced by the immune system that plays a central role in allergic reactions. High levels are associated with more severe allergies.
Omalizumab (Xolair): A widely used injectable biologic drug that works by binding to and neutralizing IgE, used to treat conditions like allergic asthma and chronic hives.
Chronic Spontaneous Urticaria (CSU): A condition characterized by the sudden appearance of itchy hives and swelling without a known external trigger, which can be debilitating.