The initial stages of oncology R&D aren’t short of intriguing new modalities, and Halda Therapeutics is planning to join them by using $126 million in fresh funding to bring its RIPTAC program into the clinic.
RIPTAC—which stands for Regulated Induced Proximity Targeting Chimeras—is being billed by the biotech as a novel “hold and kill” mechanism. In practice, this means developing a heterobifunctional molecule that targets two proteins—a cancer-specific protein and a protein with an essential function—which can kill a cancer cell while sparing non-cancerous tissue that doesn’t express the cancer-specific protein.
This “oral, selective, and widely applicable cancer cell-killing mechanism … is designed to overcome drug resistance, which is a major shortcoming of many current standard of care cancer treatments,” Halda Chief Scientific Officer Kat Kayser-Bricker, Ph.D., explained in an Aug. 12 release.
Halda Therapeutics’ tech took inspiration from the work of Yale University Professor Craig Crews, Ph.D., who founded the biotech, spurring the company’s invention of RIPTAC therapeutics. Halda is now ready to take the first of its candidates, dubbed HLD-0915, into a phase 1 trial in metastatic, castration-resistant prostate cancer in the first half of next year and has raised a $126 million series B extension to fund this work.
Some of the money will also be used to expand Halda’s team and take another RIPTAC candidate into an early-stage trial in metastatic breast cancer. Further back in development, the biotech alluded to “additional RIPTAC therapeutic programs in our pipeline to treat unmet medical needs in cancer.”
The funding round saw new investors Deep Track Capital, Frazier Life Sciences, RA Capital Management, Vida Ventures, Boxer Capital and Taiho Ventures join existing backers Canaan Partners, Access Biotechnology, Elm Street Ventures and Connecticut Innovations. The hefty haul means Halda has now raised a total of $202 million to date.
“Novel mechanisms are desperately needed to address resistance to standard of care therapies across a number of tumor types,” Joe Cabral, principal at Frazier Life Sciences, said in the release.
“RIPTAC therapies offer an ability to selectively kill cancer cells based on differential protein expression in orally bioavailable medicines,” Cabral added. “This innovation has the potential to treat both advanced cancer patients with heterogeneous resistance adaptations, as well as patients with earlier stages of disease.”
Last year, the company unveiled preclinical data it claimed showed RIPTAC therapeutics could have superior anti-tumor activity to Pfizer’s Xtandi, the standard of care for prostate cancer. At the time, Halda said it was also exploring whether its drugs could be effective as part of a combination regimen with PARP inhibitors.