Suzhou, China, August 3, 2026 - Alphamab Oncology (stock code: 9966.HK) today announced that the Center for Drug Evaluation (CDE) has approved the initiation of a Phase III clinical study (JSKN033-301) for JSKN033. JSKN033 is first-in-class high-concentration subcutaneous co-formulation comprising a HER2 bispecific antibody-drug conjugate (ADC) and a PD-L1 inhibitor. The study will compare JSKN033 with physician choice chemotherapy in patients with recurrent or metastatic cervical cancer whose disease has progressed on or after platinum-based chemotherapy and IO therapy, irrespective of HER2 expression status.
Cervical cancer remains the most common gynecological malignancy worldwide and the fourth leading cause of cancer-related death among women. Despite initial responses, patients with locally advanced or high-risk early-stage disease frequently relapse and develop distant metastases, and the five-year survival rate for advanced disease is below 20%. The current first-line standard of care — immunotherapy combined with platinum-based doublet chemotherapy, with or without bevacizumab — is recommended by both Chinese and international guidelines; however, acquired resistance ultimately leads to disease progression in the majority of patients. For those who have progressed after both platinum-based chemotherapy and IO therapy, there is no highly effective treatment other than chemotherapies.
JSKN033 uniquely integrates two innovative therapeutic modalities in a single subcutaneous injection. It combines JSKN003, a HER2 bispecific ADC, with Envafolimab (KN035), the world’s first subcutaneously administered PD-L1 inhibitor. JSKN003 is a HER2 bispecific ADC that simultaneously binds two distinct HER2 epitopes. Through site-specific glycan conjugation, a topoisomerase I inhibitor is linked to N-glycosylation sites on the anti-HER2 bispecific antibody Anbenitamab (KN026), producing a highly homogeneous product with a drug-to-antibody ratio (DAR) of 4 and substantially lower hematologic toxicity relative to other ADCs. Envafolimab is an Fc fusion protein incorporating a humanized anti-PD-L1 single-domain antibody; its low molecular weight, high water solubility and excellent stability enable rapid administration in approximately 30 seconds. JSKN033 merges these components into the first subcutaneous co-formulation of an ADC and an immune checkpoint inhibitor that is independent of hyaluronidase and enabled by a proprietary high-concentration formulation platform. This design delivers the synergistic benefits of targeted therapy and immunotherapy while allowing administration in tens of seconds, significantly improving convenience, treatment adherence and patient quality of life.
In early-phase clinical studies, JSKN033 monotherapy has already demonstrated compelling antitumor activity and a manageable safety profile in patients with cervical cancer who failed standard therapies. Detailed results will be featured in a rapid oral presentation at the upcoming European Society for Medical Oncology (ESMO) Congress 2026. Additionally, the Phase II study JSKN033-202, evaluating JSKN033 combined with platinum-based chemotherapy as first-line treatment for advanced cervical cancer, is ongoing and enrolling.
JSKN033-301 is an open-label, randomize, controlled, multicenter Phase III study designed to assess the efficacy and safety of JSKN033 versus physician choice chemotherapy in patients with recurrent or metastatic cervical cancer who have progressed on or after IO and platinum-based chemotherapy.
About JSKN033
JSKN033 is the global first high-concentration subcutaneous formulation, combining the ADC (JSKN003) with PD-L1(Envafolimab), which is independently developed by the Company. JSKN003 is developed by site-specific conjugation to the Fc glycans of Anbenitamab (KN026), resulting in a homogeneous and stable ADC with a drug-to-antibody ratio (DAR) of 4. JSKN003 binds to two HER2 epitopes on tumor cells and release topoisomerase I inhibitors through cellular endocytosis, exerting anti-tumor effects. Envafolimab is a Fc fusion protein consisting of humanized anti-PD-L1 single domain antibody and human IgG1 Fc fragment, which has been approved by Chinese authorities as the global-first subcutaneous injection PD-(L)1 inhibitor in November 2021.
JSKN033 uniquely integrates two innovative therapeutic modalities in a single subcutaneous injection. This design delivers the synergistic benefits of targeted therapy and immunotherapy while allowing administration in tens of seconds, significantly improving convenience, treatment adherence and patient quality of life.
Currently, multiple Phase II clinical studies of JSKN033 are progressing smoothly, including its use in combination with platinum‑based chemotherapy as first‑line treatment for advanced cervical cancer, as monotherapy for second‑line or above cervical cancer, and second‑line or above endometrial cancer. In addition, the Company has received approval from the Center for Drug Evaluation (CDE) to initiate a Phase III clinical study of JSKN033 as monotherapy for recurrent or metastatic cervical cancer in patients who have failed platinum‑based chemotherapy and PD‑1/PD-L1 inhibitors.
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.
Two products have 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; and Anbenitamab (KN026, brand name: 恩尼妥®), the first domestically developed HER2 bispecific antibody approved for marketing in China, redefining the standard of treatment for second‑line HER2‑positive gastric cancer. Six bispecific ADC and dual-payload ADC candidates are currently in clinical development, and next-generation ADC pipelines 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, enabling patients to achieve long-term, high-quality survival and delivering China-innovated cancer therapies to benefit patients worldwide.
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