SGO 2026 – BioNTech’s Enhertu me-too comes up short

BioNTech/DualityBio’s HER2-targeting ADC trastuzumab pamirtecan is heading to regulators in relapsed endometrial cancer, but data presented at the Society of Gynecologic Oncology conference on Saturday suggest that it has fallen somewhat short of AstraZeneca/Daiichi Sankyo’s similarly acting Enhertu. An endometrial cohort of the phase 1/2 DB-1303-O-1001 trial found an ORR of 48% and median PFS of 8.1 months among 96 centrally tested patients receiving trastu-P. By contrast, the Destiny-Pantumor02 trial of Enhertu produced ORR and mPFS of 58% and 11.1 months respectively – albeit in just 40 patients. Enhertu received FDA accelerated approval in HER2-positive (IHC 3+) cancers with no other satisfactory options in 2024. BioNTech highlighted results across HER2 expression levels; Destiny-Pantumor02 didn’t include the lowest expressers, IHC1+, but produced similar data in ICH2+ endometrial patients without securing approval in these expressers. Meanwhile, 5% of patients receiving BioNTech’s project had grade 3 or higher interstitial lung disease or pneumonitis – also a known toxicity with Enhertu, with three treatment-related ILD deaths across Destiny-Pantumor02. A confirmatory phase 3 of trastu-P in relapsed endometrial cancer, Fern-EC-01, began last year; notably, this enrols IHC1+, IHC2+ and IHC3+ patients.

Cross-trial comparison of HER2 ADCs in relapsed HER2-expressing endometrial cancer

Note: centrally tested pts. Source: Society of Gynecologic Oncology 2026 & ESMO 2023.