The US Food and Drug Administration (FDA) has granted breakthrough therapy designation for BioNTech and Duality Biologics’ (DualityBio) antibody-drug conjugate (ADC) candidate, BNT323/DB-1303, to treat advanced endometrial cancer.
The human epidermal growth factor receptor 2 (HER2)-targeting ADC is intended for patients who have advanced on or following therapy with immune checkpoint inhibitors.
The development is based on topline safety and efficacy findings from the Phase I/II clinical trial of BNT323/DB-1303 under way in HER2-expressing advanced endometrial cancer patients.
The ADC offers encouraging signs of anti-tumour activity in heavily pre-treated subjects.
The treatment provided an unconfirmed objective response rate of 58.8% and a 94.1% unconfirmed disease control rate.
It was well tolerated with a manageable safety profile in all trial subjects.
BioNTech chief medical officer and co-founder professor Özlem Türeci stated: “The breakthrough therapy designation for BNT323/DB-1303 shows the potential of our ADC candidate to address current treatment challenges for patients with advanced HER2-expressing endometrial cancer who progressed under several lines of systemic therapy.
“For these patients, the survival rates are still low and the medical need for new and more effective treatments remains high.”
In January 2023, the ADC received fast-track designation from the FDA to treat endometrial cancer.
Designed using DualityBio's duality immune toxin antibody conjugates platform, the candidate has demonstrated antitumour activity in HER2-positive and HER2-low tumour models and a range of solid tumour indications.
BNT323/DB-1303 showed potential to act on HER2 in solid tumours regardless of its expression level in preclinical and initial clinical research.
It is currently being analysed in a Phase III clinical trial to treat hormone receptor-positive and HER2-low metastatic breast cancer patients.
The latest development comes after BioNTech launched a new messenger RNA vaccine manufacturing facility in Kigali, Rwanda.
