Halda Therapeutics

Craig Crews is no stranger to the challenge of devising a punchy name for a new class of drug. The chemical biologist was involved in both the discovery and the naming of proteolysis-targeting chimeras, or PROTACs, which are double-ended molecules that degrade proteins. When Crews founded Halda Therapeutics to develop another new class of drug, he and the leadership team—including Executive Chair Tim Shannon and Chief Scientific Officer Kat Kayser-Bricker—wanted to give these molecules a moniker that’s a little graver. “We wanted to kill cells,” Crews says. “We had to figure out a way to make sure that RIP found its way into the name.” And so regulated induced proximity targeting chimeras, or RIPTACs, were christened. As the moniker suggests, a double-ended RIPTAC brings two proteins together. With one end, it binds a protein that is overexpressed in a tumor, which helps the RIPTAC get to, and stay inside, the