Hummingbird's HER3-targeted ADC entices Endeavor to sign $430M licensing deal

The buzz around HER3-targeting antibody-drug conjugates (ADCs) continues to grow. Only a week after BioNtech got in on the action, Endeavor BioMedicines has secured the rights to Hummingbird Bioscience’s preclinical contender.

The companies aren’t breaking down the financial details of the deal, but we do know that Hummingbird will be eligible to receive upfront and milestone payments from Endeavor totaling up to $430 million, plus a slice of the royalties. In return, it’s handing over the exclusive worldwide license of HMBD-501, a next-generation HER3-targeted ADC with an exatecan payload.

While AstraZeneca and Daiichi Sankyo have enjoyed success with their HER2-directed ADC Enhertu, companies have already turned to HER3 as another target of interest. Daiichi itself is working on a candidate called patritumab deruxtecan, while BioNTech paid $70 million upfront last week for MediLink Therapeutics’s own entrant in the space.

Explaining the rationale behind Endeavor’s move into the arena, CEO John Hood, Ph.D., said HER3 is “more broadly expressed on tumors than HER2 and is expressed on tumors that do not express HER2.”

“This exclusive license with Hummingbird Bio provides Endeavor with a potential best-in-class HER3-ADC, with the opportunity to treat a large number of patients in multiple tumor types,” Hood added in the Oct. 19 release. “This next-generation ADC has the potential to address significant unmet clinical needs in areas left behind by HER2 agents.”

Hummingbird has designed HMBD-501 with the aim of being a “best in class” HER3 ADC that has “a wider therapeutic index” than other options in development, the biotech’s CEO Piers Ingram, Ph.D., explained in the release. “We are pleased to license HMBD-501 to the experienced Endeavor team to bring the molecule into the clinic and a step closer to benefiting patients.”