Organs Without Brains: A Startup’s Bold Plan to Replace Animal Testing

A Bay Area biotech startup, R3 Bio, backed by Immortal Dragons and billionaire Tim Draper, is pursuing nonsentient “organ sacks”—genetically engineered, brainless whole-organ systems—to replace animal testing and someday provide human tissues and organs. Initially targeting monkey organ sacks for toxicology testing, the company envisions using stem cells and gene editing to grow complex organ structures, addressing both ethical concerns with animal use and rising demand for organs amid shortages. Experts note the concept is theoretical and raise ethical questions about how such entities would be created, stored, or whether they could have awareness, but proponents argue the approach could offer a scalable alternative to current models. The effort aligns with a broader shift away from primate testing in the US and seeks to expand beyond testing to potential future replacement parts for humans.