Hoping to challenge blockbuster breast cancer franchises, a small Dutch biotech says its ADC passed a PhIII test
For the last several years, an under-the-radar challenger to Big Pharma’s breast cancer franchises has been working on an antibody drug conjugate involving Herceptin. On Tuesday, the Dutch biotech revealed the program had met its primary endpoint in a Phase III study, and they say they’re ready to make a deal.
Byondis’ ADC, combining Herceptin with the experimental drug duocarmazine, reached its goal of a statistically significant improvement of progression-free survival over physician’s choice, the biotech said early Tuesday. None of the data were revealed in the topline results, but Byondis noted it plans to submit its pitch to the FDA by the end of the year.
The biotech stayed mum on the secondary endpoints as well, which included overall survival, objective response rate, investigator-assessed PFS, patient reported outcomes and safety and tolerability.
Formerly known as Synthon Biopharmaceuticals, a subsidiary of Synthon in the Netherlands, Byondis rebranded in April 2020 after a British private equity firm bought out its holding company in November 2019. The founder of the subsidiary elected to spin out as its own operation, and completed its relaunch soon after.
Their program, officially classified as [vic-]trastuzumab duocarmazine, works similarly to targeted chemotherapy treatments, Byondis said. After binding to HER2 on cancer cells, it activates the necessary cytotoxin to potentially induce tumor cell death. The company says if the cytotoxin is accidentally released early, it “rapidly self-destructs” to limit systemic toxicity.
That aspect of the ADC is derived from the family of synthetic duocarmycin, first isolated from Streptomyces bacteria in the 1970s.
If everything goes as planned, Byondis will sit alongside the ranks of other Herceptin-based ADCs that have made their way into the marketplace. AstraZeneca’s Enhertu follows a similar model as does Roche’s Kadcyla, which was the first ADC approved to target HER2-positive metastatic breast cancer.
And Byondis has been here before, having previously sold a Herceptin biosimilar to Amgen back in 2012.
Tuesday’s results come from a Phase III study that enrolled 436 breast cancer patients who had failed at least two lines of HER2-targeting therapies or progressed on Kadcyla. Patients were randomized to the experimental drug arm at a 2-to-1 ratio and received treatments until disease progression or unacceptable toxicity.
Byondis is also testing the candidate in four other clinical studies, including a Phase II in HER2-expressing recurrent, advanced or metastatic endometrial cancer and a Phase I in combination with GlaxoSmithKline’s Zejula in HER2-expressing locally advanced or metastatic solid tumors.
Social: Marco Timmers, Byondis CEO