BioNTech pays $170M to add would-be Enhertu rival to pipeline, expanding into ADCs in the process

BioNTech is putting its COVID-19 vaccine dollars to work to add a new modality to its pipeline. Sitting on $15 billion, the German biotech has doled out $170 million upfront for the rights to two antibody-drug conjugates (ADCs) in development at China’s Duality Biologics.

Germany-based BioNTech has long since expanded beyond the mRNA modality that made its name, adding cell therapies, antibodies and small-molecule immunomodulators to its pipeline to attack cancer from multiple angles. The antibody section of the clinical pipeline features bispecifics and monoclonals but has lacked ADCs until now.

To expand its pipeline, BioNTech has struck a deal for the ex-China rights to DB-1303 and DB-1311, a pair of ADCs that DualityBio is advancing as cancer therapies. DB-1303, a topoisomerase-1 inhibitor directed at HER2 by a conjugated antibody, is the more advanced of the two candidates. 

DualityBio kicked off a phase 1/2 clinical trial of DB-1303 in 2019. The trial, which features sites in the U.S., Australia and China, is studying the ADC in HER2-expressing advanced solid tumors. DB-1303 has fast-track designation in the U.S.

The concept of using ADCs against HER2-expressing solid tumors is well established, with AstraZeneca and Daiichi Sankyo linking Enhertu to improved outcomes in breast and lung cancer patients. Perhaps most notably, the approved ADC moved the needle in HER2-low breast cancer to expand the patient population beyond people eligible for treatment with other HER2 drugs such as Herceptin.

DB-1303 has ceded a sizable head start to Enhertu and delivers a similar payload to the incumbent. But BioNTech has decided the candidate is still worth pursuing, leading it to hand over the upfront fee and commit to milestones that could exceed $1.5 billion for rights to it and another ADC. BioNTech pointed to a favorable safety profile and a potentially expanded therapeutic window as strengths of DB-1303.

Less is known about the second ADC, DB-1311. DualityBio lists the ADC as a preclinical solid tumor drug. Like DB-1303, the ADC consists of a topoisomerase-1 inhibitor attached to an antibody using DualityBio’s linker technology. Based on preclinical data, BioNTech thinks the wide therapeutic window and safety profile of DB-1311 support its development in a wide range of cancers. 

The deal is the latest in a series of agreements struck by BioNTech. Talking to investors last week, Ryan Richardson, chief strategy officer at BioNTech, said the focus is on synergistic assets to complement the proprietary pipeline. Richardson cited the recent OncoC4 deal for a CTLA-4 drug as an agreement that hits the sweet spot, pointing to its differentiated profile and single agent and combination applications.