BioNTech and DualityBio branch out

Until now BioNTech’s phase 3 efforts with its DualityBio-partnered anti-HER2 ADC BNT323 have mirrored those of its key rival, Daiichi Sankyo/AstraZeneca’s juggernaut Enhertu. This is about to change, however: BNT323’s latest pivotal study, just unveiled on the clinicaltrials.gov registry, concerns endometrial cancer. Not only is Enhertu not in phase 3 development in this cancer type, it barely appears to have been tested in this setting at all. OncologyPipeline reveals that one relevant trial, an uncontrolled phase 2 study called Statice, was carried out in Japan; this tested Enhertu in HER2-positive uterine carcinosarcoma patients who had received chemotherapy, and showed ORRs of 55% in 22 HER2-high patients and 70% in 10 HER2-low patients, with one subject experiencing grade 3 pneumonitis/interstitial lung disease. BioNTech licensed BNT323 from DualityBio for $170m up front a year ago, and the new phase 3 study will compare the ADC against physician’s choice chemo in 468 patients with HER2-positive endometrial cancer progressed on platinum therapy.

A battle of two HER2 ADCs

Notes: ^drug-to-antibody ratio; *approved use. Source: OncologyPipeline & prescribing information.

On 5 April 2024 Enhertu was approved for second-line HER2-positive solid tumours, a use that would be expected to include second-line HER2-positive endometrial cancer; however, this is on an accelerated basis, based on remission rates in the phase 2 Destiny-Pantumor02 study and two other mid-stage trials.