Dutch biopharma Byondis announced that the U.S. FDA issued a complete response letter for the company’s lead asset, an anti-HER2 antibody-drug conjugate (ADC) for breast cancer treatment.
With its BLA, Byondis sought approval for SYD985 in HER2-positive unresectable locally advanced or metastatic breast cancer — a disease with a high unmet medical need.
According to Byondis, the agency requested additional information that “requires time and resources that extend beyond the current evaluation period.”
Byondis submitted its BLA to the FDA back in July of last year, along with a Marketing Authorization Application to the EMA. The EMA’s decision is still pending and is expected between April 2023 and October 2023.
The BLA and MAA were supported by data from the phase 2 TULIP trial comparing SYD985 to physician’s choice (PC) treatment in patients with pre-treated HER2-positive unresectable breast cancer. The study met its primary endpoint of progression-free survival, demonstrating a statistically significant improvement of 2.1 months over PC. The trial also demonstrated supportive overall survival.
Despite the CRL, Byondis remains optimistic about SYD985’s potential and is working with the FDA on the next steps. “We continue to believe that SYD985 can present a meaningful treatment option for patients living with HER2-positive metastatic breast cancer,” said Byondis CEO Marco Timmers.
HER2 has become an increasingly popular target for drugmakers in the cancer space. Back in April, BioNTech signed a $1.5 billion deal with China-based biotech DualityBio to co-develop and commercialize two cancer ADCs candidates, including DualityBio’s lead candidate, DB-1303, which is a topoisomerase-1 inhibitor-based ADC directed against HER2. Eisai and China-based Bliss Biopharmaceutical just announced a clinical trial collaboration agreement — with the option to license — for BlissBio’s ADC candidate directed against HER2 for the treatment of cancers.
SYD985 is also in development for uterine cancer and solid tumors.