High-affinity omalizumab variants with optimized disruptive potency prevent anaphylaxis in vivo.

BACKGROUND

Omalizumab, a therapeutic mAb targeting IgE, is approved for the treatment of multiple allergic indications. However, its moderate affinity for IgE necessitates frequent high-dose administrations, limiting its therapeutic use and efficacy. Attempts to develop next-generation anti-IgE antibodies with improved affinity, such as ligelizumab or HAE1, have yielded alternatives that are either less safe or not demonstrably superior.

OBJECTIVE

We sought to generate optimized omalizumab variants featuring 2 specific molecular enhancements: increased IgE binding affinity while preserving epitope specificity to enhance target neutralization and improved potency to actively dissociate prebound IgE from its high-affinity receptor FcεRI.

METHODS

Using a targeted yeast display selection strategy applied to mutated omalizumab libraries, we identified the anti-IgE clone C03 and engineered 2 flexible variants, C03-H1L2 and C03-H2L2.

RESULTS

The C03 antibodies demonstrated approximately 10-fold higher IgE binding affinity compared with omalizumab, resulting in superior inhibition of IgE binding to FcεRI. Furthermore, C03-H1L2 and C03-H2L2 exhibited enhanced potency in displacing FcεRI-bound IgE from humanized mouse mast cells and human basophils without triggering spontaneous cell activation. In a systemic anaphylaxis mouse model, single-dose administration of the flexible C03 variants, in contrast to omalizumab, desensitized allergic effector cells within 36 hours, fully preventing antigen-induced anaphylaxis.

CONCLUSIONS

These findings underscore the importance of engineering next-generation anti-IgE therapies with higher affinity and disruptive potency to optimize current treatment approaches.