LP-003 Shows Promise vs. Omalizumab in Chronic Spontaneous Urticaria Trial

Adults living with chronic spontaneous urticaria (CSU), often characterized by persistent hives and itching despite antihistamine treatment, may have a new therapeutic option on the horizon. Recent phase 2 trial data, presented at the American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting on March 23, 2026, suggest that LP-003, a novel anti-IgE antibody developed by LongBio, significantly reduces disease activity compared to placebo and, in some measures, even outperforms omalizumab, a currently approved treatment. The findings offer a potential pathway to more effective and convenient treatment for this often debilitating condition.

Understanding Chronic Spontaneous Urticaria

CSU is a complex condition where hives (wheals) and intense itching appear on the skin without an identifiable trigger. Unlike urticaria caused by allergies or infections, CSU is considered chronic when symptoms persist for more than six weeks. The underlying cause often involves an overactivation of the immune system, specifically involving immunoglobulin E (IgE) antibodies. Current treatment typically begins with antihistamines, but a significant number of patients don’t achieve adequate relief, necessitating alternative therapies like omalizumab, which targets IgE. The FDA recently approved the first oral therapy for CSU in late 2025, but additional treatment options are still needed.

LP-003: A New Approach to IgE Inhibition

LP-003, like omalizumab, works by targeting IgE, but it represents a potentially improved approach. Ming Xie, business development at LongBio, explained that the phase 2 study results indicate the molecule may be effective in CSU with a favorable safety profile and the possibility of less frequent dosing. Currently, omalizumab requires administration every four weeks, whereas some LP-003 regimens in the trial were evaluated every eight weeks. This could translate to increased convenience and potentially better adherence for patients.

Phase 2 Trial Design and Key Findings

The multicenter, double-blind, placebo-controlled phase 2 study involved 202 adults with moderate to severe CSU whose symptoms were not adequately controlled by antihistamines. Participants were randomly assigned to one of five treatment groups: three different doses of LP-003 (100 mg every 8 weeks, 200 mg every 8 weeks, and 200 mg every 4 weeks), omalizumab (300 mg every 4 weeks), or a placebo. All treatments were administered in addition to stable-dose antihistamines.

The primary endpoint of the study was the change in weekly urticaria activity score (UAS7) from baseline to week 12. UAS7 is a standardized measure used to assess the severity of CSU symptoms, taking into account both the number and intensity of hives and the degree of itching. Researchers found that all three LP-003 groups experienced significant reductions in UAS7 compared to the placebo group. Notably, the LP-003 200 mg administered every eight weeks demonstrated a significantly greater decrease in UAS7 at week 12 than omalizumab (least-squares mean difference, –4.78; 95% CI, –8.57 to –0.99; P = .0137).

a higher proportion of patients in the LP-003 groups achieved a UAS7 score of zero – indicating complete symptom resolution – at both week 4 and week 12 compared to the placebo group. Specifically, 66.7% of patients receiving LP-003 200 mg every eight weeks achieved a UAS7 of zero at week 12, compared to 43.6% in the omalizumab group (difference, 23.1; 95% CI, 1.1-42.2; P = .0405). This suggests a potentially faster onset of action with LP-003.

Safety Profile and Adverse Events

The safety profile of LP-003 appeared generally favorable in the phase 2 trial. The incidence of adverse events was comparable across the LP-003 groups, omalizumab, and placebo. Serious adverse events were reported in a compact percentage of patients in each group, but none were deemed to be treatment-related. Only one patient discontinued treatment due to an adverse event – a case of erythema multiforme in the omalizumab group.

What’s Next for LP-003?

The promising results from the phase 2 trial pave the way for further investigation of LP-003 in a phase 3 study. LongBio plans to determine the optimal dose and study design for the phase 3 trial after consulting with China’s regulatory agency. This next phase will be crucial to confirm the efficacy and safety of LP-003 in a larger patient population and to ultimately seek regulatory approval for its use in treating CSU. The company is also exploring potential applications of LP-003 in other IgE-mediated allergic conditions.

For individuals managing CSU, it’s important to continue working closely with a qualified healthcare professional to develop a personalized treatment plan. Staying informed about emerging therapies and participating in clinical trials, when appropriate, can also be valuable steps in managing this challenging condition. You can find more information about CSU and available treatments from organizations like the National Eczema Association.