May 14, 2026 — Henlius (2696.HK) announced that the Japan bridging study (NCT06812260) of its self-developed anti-PD-1 mAb serplulimab (trade name: Hetronifly^® in Europe), in combination with chemotherapy for the first-line treatment of extensive-stage small cell lung cancer (ES-SCLC), has successfully completed patient enrolment.

The study is designed to evaluate the efficacy and safety of serplulimab in combination with chemotherapy as a first-line treatment for ES-SCLC in Japanese patients. The trial is led by Dr. Takayasu Kurata of Kansai Medical University Hospital.

Dr. Takayasu Kurata, M.D., Ph.D., the leading principal investigator of the NCT06812260 study from Kansai Medical University Hospital, said: “The completion of enrolment in this bridging study marks a key step in evaluating the efficacy and safety of serplulimab in Japanese patients with extensive-stage small cell lung cancer. We look forward to this PD-1 inhibitor— the first of its kind approved globally for first-line treatment of small cell lung cancer—bringing a new treatment option to patients in Japan.”

Jing Li, Vice President of Global Product Development at Henlius, said: “Serplulimab has been approved in over 40 countries and regions worldwide. The completion of enrolment in this Japan bridging study represents an important milestone in advancing its clinical development and regulatory progress in Japan. We will continue to strengthen communication with local regulatory authorities and accelerate its development and registration in the Japanese market.”

The NCT06812260 study, together with results from the ASTRUM-005 study—which supported approvals of serplulimab for ES-SCLC in China and Europe—will serve as key clinical evidence for regulatory submission in Japan. Henlius plans to submit the marketing application in collaboration with its partner Eisai during its fiscal year 2026. ASTRUM-005 is a randomized, double-blind, placebo-controlled, international Phase 3 study to evaluate serplulimab for first-line treatment of ES-SCLC. The results were first presented as an oral presentation at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting and subsequently published in The Journal of the American Medical Association (JAMA)—marking the first small-cell lung cancer immunotherapy study ever featured in JAMA’s main edition. At the 2025 ASCO Annual Meeting, the final analysis of ASTRUM-005 was released: as of December 31, 2024 (median follow-up 42.4 months), the four-year overall survival (OS) rate was 21.9% in the serplulimab group versus 7.2% in the control group, with a manageable safety profile—further validating its durable survival benefit for patients with ES-SCLC.

Building on these positive results, serplulimab has been granted Orphan Drug Designations (ODDs) by regulatory authorities of multiples countries, including the U.S. FDA, for the treatment of SCLC and has been approved for first-line treatment of ES-SCLC in over 40 countries and regions including China, the U.K., EU, Singapore, India, Switzerland, and Peru. Serplulimab’s clinical data in SCLC have been included in the ESMO Magnitude of Clinical Benefit Scale (MCBS), ranking higher than peer products. Notably, the ASTRIDE study, a bridging clinical trial of serplulimab conducted in previously untreated ES-SCLC patients in the United States—comparing it with the standard first-line treatment atezolizumab (a PD-L1 inhibitor)—also successfully completed patient enrolment in October 2025.

As part of its strategic expansion in Japan, Henlius entered into an exclusive commercialisation agreement, as well as a co-exclusive development and manufacturing license agreement, with Eisai in February 2026 for serplulimab. Under the terms of the agreement, Eisai will hold exclusive commercialisation rights for serplulimab in Japan, while Henlius will serve as the Marketing Authorisation Holder (MAH) for the product in Japan, a status it officially obtained in February 2026.

Henlius will continue to advance the global clinical development and regulatory progress of serplulimab. Through clinical practices aligned with international standards, the company is committed to building robust cross-regional clinical evidence and delivering innovative treatment options that are accessible and aligned with real-world clinical needs for patients worldwide.

About Serplulimab

Serplulimab is a recombinant humanized anti-PD-1 mAb injection (trade name: Hetronifly^® in Europe). It is the world’s first anti-PD-1 mAb approved for first-line treatment of small cell lung cancer (SCLC) and has been approved for marketing in over 40 countries and regions including China, the U.K., EU, Singapore, India, Switzerland, and Peru.

In March 2022, serplulimab was officially approved for marketing in China and is currently indicated for the treatment of squamous non-small cell lung cancer (sqNSCLC), extensive-stage small cell lung cancer (ES-SCLC), esophageal squamous cell carcinoma (ESCC), and non-squamous non-small cell lung cancer (nsqNSCLC).

Henlius continues to advance an extensive global clinical programme for serplulimab, with more than 10 combination immunotherapy studies ongoing worldwide and over 5,100 patients enrolled, with over 30% of patients enrolled in two pivotal international studies being Caucasian, making it one of the anti-PD-1 mAbs with the most extensive international clinical data. Bridging studies for ES-SCLC are being conducted in the United States and Japan.

In gastrointestinal cancers, ASTRUM-006, the phase 3 study is evaluating serplulimab in perioperative gastric cancer, including neoadjuvant combination therapy and adjuvant monotherapy, representing a novel treatment approach.¹ As the world’s first perioperative regimen for gastric cancer to replace adjuvant chemotherapy with immunotherapy monotherapy, its New Drug Application (NDA) has been accepted by the National Medical Products Administration (NMPA) and granted Priority Review. The indication is expected to be approved in China in 2026. In colorectal cancer, ASTRUM-015, the global phase 3 study evaluating serplulimab in combination with bevacizumab and chemotherapy for first-line treatment of metastatic colorectal cancer (mCRC) has completed patient enrolment, while emerging data from its phase 2 stage further underscore serplulimab’s potential to expand its clinical value across high-burden gastrointestinal malignancies.²

Three pivotal clinical studies of serplulimab have been published in leading journals including The Journal of the American Medical Association (JAMA), Nature Medicine, and the British Journal of Cancer. In addition, serplulimab has been included in several authoritative clinical guidelines, such as the CSCO Guidelines for SCLC, NSCLC, ESCC, Colorectal Cancer, Clinical Application of Immune Checkpoint Inhibitors, and Chinese Guidelines for Radiotherapy in Esophageal Cancer, providing important references for oncology clinical practice. Internationally, serplulimab for the treatment of SCLC has been granted Orphan Drug Designations (ODDs) by regulatory authorities of multiples countries, including the U.S. FDA.

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