Duality Biologics has shared the first data from a phase 1/2a antibody-drug conjugate (ADC) trial, giving an early look at how the BioNTech-partnered asset is shaping up against rival molecules in development at companies including Merck & Co.
The DualityBio ADC is aimed at B7-H3, a target that has caught the eye of multiple companies. BioNTech bought a spot in the race last year when it paid $170 million upfront for rights to the B7-H3 candidate DB-1311, now also known as BNT324, and another ADC. China’s DualityBio began a global phase 1/2 study of DB-1311 months after striking the deal with BioNTech.
DualityBio shared data on the first 277 patients at ESMO Congress Asia 2024. The biotech reported a response rate of 32.4% across the study, which enrolled pretreated patients with various locally advanced or metastatic solid tumors.
The breakdown of the data by tumor type provides a clearer look at how DB-1311 looks versus its rivals, with the caveat that such cross-trial comparisons can be misleading. DualityBio saw responses in 56.2% of the 73 patients with small cell lung cancer (SCLC), an indication in which Merck and Daiichi Sankyo are at the front of the pack. The DualityBio result includes unconfirmed responses.
Daiichi began enrolling SCLC patients in a phase 3 trial of its B7-H3-directed ADC in May. The candidate demonstrated its potential in a study that linked the phase 3 dose to a 54.8% response rate in 42 SCLC patients. Daiichi reported median progression-free and overall survival of 5.5 months and 11.8 months, respectively. DualityBio’s press release lacks data for those endpoints.
The release does include data on how the ADC performed in non-small cell lung cancer (NSCLC) and castration-resistant prostate cancer (CRPC). In squamous and non-squamous NSCLC, DualityBio reported unconfirmed response rates of 22% and 16%, respectively.
The unconfirmed response rate in CRPC was 28%. MacroGenics reported unconfirmed response rates of 26.7% and 46.9%, respectively, at a lower and higher dose, in a phase 2 trial of its B7-H3 ADC in CRPC. DualityBio saw an immature median progression-free survival (PFS) of 7.2 months and a six-month PFS rate of 94.7% in CRPC. MacroGenics’ figures were around eight months and 70%, respectively.
DualityBio and BioNTech have identified a trial in patients with SCLC or NSCLC as the next step for their B7-H3 ADC. A phase 1/2 trial is scheduled to start next year to assess the effect of combining the ADC with a PD-L1xVEGF-A bispecific, the mechanism that is threatening to topple Keytruda and its ilk.