Suzhou, China, December 23, 2025 - Alphamab Oncology (stock code: 9966.HK) announced that Envafolimab (KN035) has been granted Orphan Drug Designation (ODD) by the U.S. Food and Drug Administration (FDA) for the treatment of gastric cancer and gastroesophageal junction cancer (GC/GEJ). This marks the third ODD awarded to Envafolimab, following previous designations for advanced biliary tract cancer and soft tissue sarcoma.
GC/GEJ is among the most prevalent malignant tumors worldwide, with limited treatment options and poor prognosis for certain subtypes. In the U.S., the SEER database model predicts that there will be 26,890 new cases and 10,880 new deaths of GC/GEJ in 2024, with a five-year overall survival rate of less than 40%. Fluoropyrimidine and platinum-based regimens are commonly used as first-line treatments. Available second-line or later-line treatment options include paclitaxel plus ramucirumab, paclitaxel, docetaxel or irinotecan, and best supportive care, with objective response rates of approximately 15-25%. The median overall survival is approximately 8-9 months for second-line treatment and 4-6 months for later lines.
Envafolimab is the world’s first subcutaneously injectable PD-L1 inhibitor. Patients can complete administration within 30 seconds, making it particularly suitable for frail, elderly patients and those with adverse reactions to intravenous infusions. This ODD was granted based on the antitumor efficacy demonstrated in a previous Phase II clinical study for advanced GC/GEJ. The combination regimen of Envafolimab and FOLFOX achieved an objective response rate (ORR) of 60% and a disease control rate (DCR) as high as 100%, with a favorable safety and tolerability profile. No adverse events leading to treatment discontinuation or death were reported. This therapy is expected to provide a more effective immunotherapy option for patients with gastric cancer.
The "Orphan Drug Designation", originated from the Orphan Drug Act (ODA), is a U.S. FDA initiative aimed at encouraging the development of innovative drugs for the treatment of diseases affecting fewer than 200,000 people in the U.S. The designation of JSKN003 will be beneficial to obtain relevant policy supports for subsequent research and development, registration, and commercialization in the U.S., including funding for research and development costs, tax credits for clinical trial expenditures, waiver of prescription drug user fee, accelerated review and approval processes, and, upon approval, the potential for seven years of market exclusivity in the U.S. These incentives are expected to significantly accelerate Envafolimab 's development progress and market entry efficiency in this therapeutic area.
About Envafolimab（KN035）
Envafolimab (KN035) is independently invented by Alphamab Oncology，and co-developed with 3D (Beijing) Medicines since 2016. On March 30, 2020, Alphamab Oncology, 3DMed, and Simcere reached a strategic cooperation, whereby Alphamab Oncology is responsible for production and quality control, and 3DMed is responsible for the clinical development in oncology field, and Simcere is responsible for the exclusive commercial promotion of products in mainland China.
Envafolimab is an subcutaneous PD-L1 single-domain antibody Fc fusion protein. It was approved for marketing in China in November 2021, for the treatment of unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) solid tumors.
Envafolimab efficiently blocks the binding of PD-1 and PD-L1, thereby activating an immune response against tumors. With a molecular weight half that of a conventional antibody, it exhibits enhanced tissue penetration and reaches tumor tissues via the lymphatic circulation system. Envafolimab offers significant advantages in convenience and compliance by avoiding intravenous infusion and can be administered in just 30 seconds, making it particularly suitable for frail, elderly, or IV-intolerant patients.
Multiple clinical trials for Envafolimab are currently underway to further expand its indications.
Envafolimab has been granted three Orphan Drug Designations by the U.S. Food and Drug Administration (FDA) for the treatment of advanced biliary tract cancer, soft tissue sarcoma, and gastric cancer and gastroesophageal junction cancer; it has been granted Breakthrough Therapy Designation by the National Medical Products Administration (NMPA) for the treatment of unresectable or metastatic solid tumors with high tumor mutation burden (TMB-H).
About Alphamab Oncology
Alphamab Oncology (Stock Code: 9966.HK) is an innovative biopharmaceutical company focused on oncology. Leveraging proprietary platforms-including single-domain antibodies, bispecific antibodies, glycan-specific conjugation, linker-payloads, dual-payload ADCs, and high-concentration subcutaneous formulations, the Company has built a differentiated and globally competitive pipeline, covering cutting-edge candidates in ADCs, bispecific antibodies, and single-domain antibodies.
One product has received market approval: Envafolimab (KN035, brand name: 恩维达®), the world's first subcutaneously injected PD-(L)1 inhibitor, offering greater convenience and accessibility in cancer treatment. The NMPA has accepted the new drug application for KN026 (Anbenitamab Injection), a HER2 bispecific antibody, for second-line or later HER2-positive gastric cancer. Four bispecific ADC candidates have entered clinical stages, and next-generation ADC pipelines—such as dual-payload ADCs—are advancing rapidly. The Company has established strategic partnerships with organizations including CSPC, ArriVent, and Glenmark, covering both product development and technology platforms.
Our overarching mission is to make cancer manageable and curable by addressing unmet clinical needs in oncology. Alphamab Oncology is continuously dedicated to the development of effective, safe, and globally competitive anti-tumor drugs, delivering China-innovated cancer therapies to benefit patients worldwide.
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