Adagene reports two collaboration milestones with Third Arc Bio and Exelixis

Adagene Inc. (Nasdaq: ADAG) issued two separate 6-K filings in September 2026 detailing progress on its antibody-masking collaborations.

On September 10, 2026, the company said Third Arc Bio, Inc. selected the first lead candidate under a strategic licensing agreement established in November 2025, in which Third Arc Bio uses Adagene's NEObody and SAFEbody technology platform to generate masked CD3 T cell engagers against tumor-associated antigens.¹ The agreement's terms were also amended: the companies broadened the collaboration's scope, and Third Arc Bio will now sponsor and fund clinical development of the program.¹ Adagene said the broadened scope increased the total potential development and commercial milestone payments owed to Adagene under the deal.¹ Adagene retains an option, at no cost to itself, to develop and commercialize resulting candidates in Greater China, Singapore, and South Korea, according to the filing.

Separately, on September 9, 2026, Adagene announced a milestone achievement in its ongoing collaboration and license agreement with Exelixis, Inc., tied to a preclinical milestone for a candidate called XB404, which triggered a $2.0 million payment from Exelixis.² The filing described XB404 as an ROR1/2-targeting SAFEbody construct meant to carry a cytotoxic drug payload to tumor cells while limiting toxicity to healthy tissue, according to the company. A separate, additional payment was also triggered after candidates were chosen for a second SAFEbody-based antibody-drug conjugate program under the same partnership, per the filing. Adagene is eligible to receive further development and commercialization milestones plus royalties on net sales of any resulting products.²