RAPT and Jemincare Announce License for New Long-Acting anti-IgE Antibody

RAPT Therapeutics, Inc., a company focused on immunology-based biopharmaceutical developments, has entered into a pivotal agreement with Shanghai Jemincare Pharmaceutical Co., Ltd., a major player in the pharmaceutical industry in China. This collaboration is centered around JYB1904, also known as RPT904, a promising clinical-stage half-life extended anti-IgE monoclonal antibody. The agreement grants RAPT the rights to develop and commercialize RPT904 worldwide, except for mainland China, Hong Kong, Macau, and Taiwan. In exchange, Jemincare will receive an upfront payment of $35 million, with potential additional earnings from milestone payments that could cumulatively reach up to $672.5 million. Moreover, Jemincare stands to gain royalties from future sales of RPT904 in markets outside its designated territory.

RPT904 is being developed as a potential improvement over the existing anti-IgE monoclonal antibody, omalizumab, known commercially as Xolair. This antibody has applications in several allergic disorders, including food allergies, asthma, and chronic spontaneous urticaria (CSU). RAPT has plans to focus its initial development efforts on treating food allergies and aims to commence a Phase 2b clinical trial in this area by the latter half of 2025.

Jemincare, on the other hand, is actively advancing its clinical trials for JYB1904 in China, focusing on asthma and CSU. The company is in the midst of Phase 2 trials aimed at understanding the pharmacokinetic and pharmacodynamic profiles of JYB1904 in comparison to omalizumab. These trials are crucial for determining appropriate dosing for potential future Phase 3 trials. The Phase 2 asthma trial is expected to yield topline results in the second half of 2025, while the CSU trial outcomes are anticipated in the first half of 2026.

Jemincare has previously completed a Phase 1 study involving a randomized, double-blinded, single-dose escalation trial with healthy volunteers in China. The study assessed the safety, pharmacokinetics, and pharmacodynamics of JYB1904 against a placebo and included comparisons with omalizumab. The findings indicated that JYB1904 was generally well-tolerated, with only mild adverse effects noted. Importantly, the pharmacokinetic data revealed that JYB1904 possesses more than double the half-life of omalizumab, suggesting a potentially longer-lasting therapeutic effect. Additionally, JYB1904 demonstrated a more significant and sustained reduction in free IgE levels and higher total IgE accumulation compared to omalizumab at similar doses, further highlighting its potential advantages.

The leadership at both RAPT and Jemincare has expressed enthusiasm about this collaboration. Brian Wong, President and CEO of RAPT, highlighted the growing market for food allergy treatments and the potential of RPT904 to become a leading treatment option. Xiaoxiang Li, President of Jemincare, emphasized the strategic importance of this partnership in accelerating the development and commercialization of JYB1904, with the goal of benefiting patients with allergic disorders.

This partnership represents a significant step in the field of immunology-based therapeutics, potentially offering new hope for patients dealing with challenging allergic conditions. As the clinical trials progress, the outcomes will be eagerly awaited by the medical community, patients, and stakeholders involved in the treatment of allergic diseases.