Alphamab Oncology Announces the First Patient Dosed in a Phase III Clinical Study for Triple-Negative Breast Cancer of TROP2/HER3 Bispecific ADC JSKN016

SUZHOU, China, March 20, 2026 /PRNewswire/ -- Alphamab Oncology (stock code: 9966.HK) today announced that the first patient has been dosed in a phase III clinical study (JSKN016-301) evaluating JSKN016, a novel TROP2/HER3 bispecific antibody-drug conjugate (ADC) for the treatment of triple-negative breast cancer (TNBC). This milestone brings another innovative bispecific ADC from the company's pipeline into pivotal development, reinforcing its potential to offer a more effective and safer treatment option for patients with TNBC.

Breast cancer is the most commonly diagnosed malignancy among women worldwide, with a growing disease burden. TNBC accounts for approximately 15–20% of all breast cancer cases and is characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. This subtype is associated with high invasiveness, increased recurrence rates, and poor prognosis. For patients with locally advanced or metastatic TNBC who have progressed after at least one line of systemic chemotherapy (particularly taxane-based therapy), subsequent treatment options remain limited. Current therapies typically yield objective response rates (ORR) of only 10–20% and median progression-free survival (mPFS) of approximately one to three months, underscoring a significant unmet medical need.

JSKN016 is a bispecific ADC developed by Alphamab Oncology leveraging its proprietary single-domain antibody and bispecific antibody platforms. Designed to co-target TROP2 and HER3, JSKN016 features a homogeneous DAR4 ADC achieved through glycan-specific conjugation. This enables simultaneous blockade of tumor signaling pathways and enhanced intracellular delivery of a topoisomerase I inhibitor for precise and potent antitumor activity. Early-phase clinical studies have demonstrated encouraging antitumor activity and a favorable safety profile of JSKN016 in heavily pretreated advanced TNBC and other solid tumors.

JSKN016-301 is an open-label, randomized, controlled, multicenter phase III trial expected to be conducted at approximately 60 sites across China. The study aims to evaluate the efficacy and safety of JSKN016 versus treatment of physician's choice (TPC) in patients with unresectable locally advanced, recurrent, or metastatic TNBC who have failed at least two lines of systemic therapy. Primary endpoints are progression-free survival (PFS) and overall survival (OS) as assessed by a Blinded Independent Review Committee (BIRC) per RECIST v1.1. Secondary endpoints include investigator-assessed PFS, ORR, disease control rate (DCR), and duration of response (DoR), as well as BIRC-assessed ORR, DCR, and DoR.

About JSKN016

JSKN016 is a TROP2/HER3 targeting bispecific ADC developed using the proprietary single-domain antibody and bispecific antibody platforms. It features a homogeneous DAR4 ADC achieved through glycan-specific conjugation. JSKN016 binds to TROP2 and/or HER3 on tumor cells, blocks the corresponding signaling pathways and releases topoisomerase I inhibitors through cellular endocytosis, thereby exerting potent anti-tumor effects.

JSKN016 has demonstrated promising antitumor activity and a favorable safety profile across multiple solid tumors. Multiple clinical studies of JSKN016 as monotherapy and in combination therapies for lung cancer, breast cancer, and other indications have been initiated. The Phase III clinical study evaluating JSKN016 for the treatment of triple-negative breast cancer (TNBC) is currently ongoing.

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. Five 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, enabling patients to achieve long-term, high-quality survival and delivering China-innovated cancer therapies to benefit patients worldwide.

SOURCE Alphamab Oncology