#Japan #Tokyo #Eisai #Henlius #Serplulimab

Eisai and Henlius Form Exclusive Partnership in Japan

On February 6, 2026, Eisai Co., Ltd. and Shanghai Henlius Biotech, Inc. announced the formation of an exclusive commercial agreement for the novel anti-PD-1 monoclonal antibody, serplulimab, in Japan. Also known in the European Union as Hetronifly®, serplulimab holds promise as a new treatment for various cancers.

A Unique Antibody for Critical Cancer Treatment

Serplulimab stands out due to its unique binding mechanism, making it different from existing anti-PD-1 antibodies. In China, this innovative treatment has already gained approvals for multiple indications, such as non-small cell lung cancer (NSCLC) and advanced small-cell lung cancer (ES-SCLC), further extending to esophageal squamous cell carcinoma. The European Union has also approved serplulimab for the treatment of ES-SCLC, making it the first anti-PD-1 antibody internationally recognized as a first-line therapy for this condition.

Ongoing Studies and Anticipated Regulatory Review

In Japan, Henlius is currently conducting a phase II binding study specifically for ES-SCLC. They anticipate submitting a regulatory application based on the outcomes of this study and the supportive phase III data previously used for approvals in China and Europe during the 2026 fiscal year. Additionally, a multinational phase III clinical trial is already underway targeting metastatic colorectal cancer, with further developments expected.

Under this new agreement, Eisai will gain exclusive marketing rights for serplulimab in Japan, allowing them to lead the commercialization efforts. Henlius is poised to initiate a clinical trial focusing on perioperative gastric cancer in the Japanese market, assuming responsibility as the marketing authorization holder.

Financial Aspects of the Agreement

Eisai's financial commitment to Henlius includes an initial payment of $75 million, with regulatory milestone payments that could reach up to $80.01 million, plus potential sales-based milestone payments that could total $233.3 million. Along with these, Henlius will benefit from double-digit royalties based on product sales. Importantly, Eisai does not foresee any impact on their consolidated financial projections for the fiscal year concluding on March 31, 2026.

Leadership Perspectives

Dr. Jason Zhu, the CEO of Henlius, expressed enthusiasm about the collaboration, stating, "We are excited to work with Eisai in Japan to advance the development of serplulimab in this significant market. By merging Henlius' innovative capabilities with Eisai's thorough local expertise, we aim to meet the unmet medical needs of patients in Japan."

Eisai’s Executive Director and Japan Operations Head, Toshihiko Yusa, emphasized serplulimab’s track record for addressing major medical needs, indicating their urgency to provide Japanese patients with this treatment as soon as possible.

Conclusion

This strategic partnership between Eisai and Henlius marks a notable advancement in oncology treatment options available in Japan, thereby enhancing the potential for improved patient outcomes through innovative therapies. The collaboration not only strengthens their market positions but sets a promising precedent for future endeavors in the biopharmaceuticals sector.