In 2nd big ADC deal of the day, GSK inks $1.4B pact for Hansoh gynecology cancer asset

GSK is the latest to partake in a string of recent antibody-drug conjugate (ADC) deals, dishing out $85 million cash and up to $1.4 billion in biobucks for Hansoh Pharma’s gynecologic cancer asset. 

The exclusive licensing deal (PDF) centers around HS-20089, a B7-H4 targeted ADC currently being assessed in a phase 1a/1b clinical trial in China. After preclinical data demonstrated that the asset inhibited tumor cell growth expressing B7-H4 in vitro and in vivo, China-based Hansoh began studying the asset among patients with advanced solid tumors. The trial has an estimated enrollment of 177 people and is expected to wrap by Dec. 31 of this year, according to

Under the new agreement, GSK gains exclusive worldwide rights to HS-20089, excluding certain areas: Hansoh will keep rights in China’s mainland, Hong Kong, Macau and Taiwan.   

In exchange, GSK is paying $85 million upfront and giving Hansoh the chance to make up to $1.485 billion more in success-based milestones. If HS-20089 reaches the market, GSK will also pay out royalties on global net sales outside of the areas where Hansoh has commercialization rights. 

The transaction comes right on the heels of a separate Big Pharma ADC deal, in which Merck & Co. paid $4 billion upfront to co-develop three of Daiichi Sankyo’s ADC prospects. That pact followed an AstraZeneca deal with Daiichi for two ADCs and another in which BioNTech also got in on the fun, picking up a HER3-directed asset from ADC expert Daiichi.

ADCs merge two traditional oncology classes—antibodies and chemotherapy—to target the cancer cell while leaving healthy tissues alone.

Besides targeting B7-H4, which is overexpressed in ovarian and endometrial cancers, HS-20089 uses ADC tech such as a topoisomerase inhibitor payload—a validated mechanism of action in approved anti-cancer medicines.

GSK believes Hansoh’s asset has “best-in-class potential in ovarian and endometrial cancer with opportunities in other solid tumors,” Hesham Abdullah, M.D., GSK senior vice president and global head of oncology, R&D, said in an Oct. 20 release. The Big Pharma plans to launch phase 1 trials for HS-20089 outside of China in 2024.

Part of GSK’s strategic R&D focus includes tumor cell-targeting modalities and expertise in gynecologic cancers. The company has several investigational assets targeting endometrial cancers and multiple other ADCs being assessed in oncology. GSK also has one approved ADC: Blenrep, which won FDA approval in August 2020 for multiple myeloma patients who have failed four previous treatments.