Alphamab Oncology recently announced that its anti-HER2 biparatopic antibody-drug conjugate (ADC), JSKN003, has received approval from the U.S. FDA to initiate a Phase II clinical study for the treatment of platinum-resistant ovarian cancer, including recurrent epithelial ovarian cancer, primary peritoneal cancer, and fallopian tube cancer. This major milestone highlights the innovative potential of JSKN003 in oncology therapeutics and marks an important step forward in the global fight against cancer.

What is JSKN003?

JSKN003 is a cutting-edge biparatopic ADC developed in-house by Alphamab Oncology. It combines two key therapeutic components:

• Anti-HER2 Antibody: Targets HER2, a protein overexpressed on the surface of many cancer cells.

• Topoisomerase I Inhibitors (TOPIi): Released upon cellular endocytosis, these inhibitors have potent anti-tumor effects.

The biparatopic nature of JSKN003 means it can bind to two different epitopes on HER2, increasing its specificity and effectiveness in targeting tumor cells. This dual-target approach is what sets JSKN003 apart from traditional antibody-drug conjugates, offering enhanced serum stability and a stronger bystander effect, which widens its therapeutic window.

A Major Step for Ovarian Cancer Treatment
JSKN003's FDA IND approval enables Alphamab to advance its Phase II study for platinum-resistant recurrent epithelial ovarian cancer (PROC), which is a significant challenge in oncology due to the limited treatment options available. Phase II Study JSKN003-202 will evaluate the safety and efficacy of JSKN003 in patients who have previously undergone platinum-based chemotherapy but have shown resistance to treatment.

This study aims to determine the recommended Phase III dose (RP3D) and assess the clinical benefits of JSKN003 for ovarian cancer patients, regardless of HER2 expression levels. This is particularly important as many ovarian cancer patients do not express HER2 at high levels, making conventional HER2-targeting treatments less effective.

Global Clinical Development and Breakthrough Designation

In addition to the ongoing U.S. study, JSKN003 is also undergoing three Phase III clinical trials in China, focusing on its use for HER2-low expressing breast cancer (BC), platinum-resistant ovarian cancer (PROC), and HER2-positive breast cancer (BC).

JSKN003's innovative approach has caught the attention of regulatory bodies around the world. In March 2025, the drug received breakthrough therapy designation from the National Medical Products Administration (NMPA) of China for platinum-resistant ovarian cancer, which will help expedite its development and availability in China. Furthermore, it has also been granted Orphan Drug Designation (ODD) by the FDA for the treatment of gastric cancer and gastroesophageal junction cancer (GC/GEJ).

Alphamab Oncology: Innovating Cancer Treatment

Alphamab Oncology continues to lead in the development of innovative cancer therapies. With a strong portfolio that includes single-domain antibodies, bispecific antibodies, and antibody-drug conjugates (ADCs), the company is committed to addressing the unmet clinical needs of oncology patients worldwide. Their flagship product, Envafolimab, is the world's first subcutaneously injectable PD-(L)1 inhibitor, which has improved the convenience and accessibility of cancer treatment.

As Alphamab Oncology accelerates the development of JSKN003 and other groundbreaking therapies, they remain focused on delivering China-innovated cancer treatments to patients globally, advancing toward their mission to make cancer manageable and curable.

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Source: the Manila Times