GSK heads back to Hansoh, paying $185M upfront for another ADC

The antibody-drug conjugate (ADC) fever of recent months still shows no signs of abating, with GSK heading back to Hansoh Pharmaceutical to pick up another candidate for $185 million upfront.

The Chinese biotech will also be in line for up to $1.5 billion in milestone payments and tiered royalties. In return, GSK is getting the ex-China rights to develop and commercialize a B7-H3-targeted ADC called HS-20093.

Hansoh said the candidate, which is composed of an anti-B7-H3 monoclonal antibody linked to a topoisomerase inhibitor (TOPOi) payload, is undergoing a number of phase 1 and 2 trials in China for lung cancer, sarcoma, head and neck cancers and other solid tumors.

Explaining its rationale for the latest licensing deal, GSK said HS-20093 “has shown promising initial clinical activity in lung cancer with potential to address unmet medical need in broader solid tumor indications.”

The British Big Pharma singled out data from the ARTEMIS-001 phase 1 trial, which was presented by Hansoh at the 2023 American Society of Clinical Oncology annual meeting. The trial showed initial clinical activity in small cell lung cancer, non-small cell lung cancer and sarcoma.

The licensing deal comes two months to the day after GSK secured the rights to a B7-H4-targeted ADC called HS-20089 from Hansoh that is being investigated in the clinic to treat gynecologic cancer. The weighting of that deal was broadly similar, if slightly lower up front, than today’s announcement, with GSK handing over $85 million and pledging up to $1.4 billion in milestone payments.

“B7-H3 is highly expressed in a broad range of solid tumors where there remains a significant need for novel treatment options,” GSK’s global head of oncology R&D Hesham Abdullah said in the company’s release. “We look forward to progressing this potential new treatment across several indications and in future potential combination approaches with our established portfolio.”

GSK is just one of the Big Pharmas to have gone into a feeding frenzy over ADCs in recent months. Merck & Co. handed over an eye-watering $4 billion upfront to co-develop three of Daiichi Sankyo’s ADC prospects, following in the footsteps of AstraZeneca and BioNTech, who have both bagged their own ADCs from the Japanese company.

Only last week, Bristol Myers Squibb got in on the Chinese ADC action, handing SystImmune $800 million upfront for a phase 2 solid tumor candidate.