Day One goes where Pfizer and AbbVie feared to tread

Deals for antibody-drug conjugates are hardly unusual, but the target involved in yesterday’s tie-up between Day One and MabCare, PTK7, might raise eyebrows. This mechanism is perhaps best known for being shunned by Pfizer and AbbVie, which last year discontinued their joint PTK7-targeting ADC, cofetuzumab pelidotin, in phase 1. The only similarly acting clinical-stage asset now, according to OncologyPipeline, is Genmab’s PRO1107, gained via the $1.8bn acquisition of ProfoundBio. Still, that deal was largely driven by the latter’s folate receptor alpha-targeting ADC rinatabart sesutecan. For its part, Day One reckons the asset it has gained, now known as DAY301, uses linker-payload technology that could “overcome the limitations” of earlier PTK7-targeted ADCs. DAY301 employs a topoisomerase 1 inhibitor payload, while cofetuzumab pelidotin and PRO1107 both used tubulin inhibitors. At least Day One, which until now has been focused on small molecules including the recently approved Ojemda, hasn’t paid too much for its foray into ADCs: the deal, which gives the group exclusive rights outside Greater China, is worth $55m up front and up to $1.15bn in milestones.

The PTK7 pipeline

Source: OncologyPipeline.