Imagine a future where we can test new drugs without putting animals through painful experiments. That future might be closer than you think, thanks to a Bay Area biotech startup called R3 Bio that’s working on something pretty wild: genetically-engineered organ systems that have no brain.

The concept sounds like science fiction, but it’s grounded in real science. R3 Bio, backed by billionaire investor Tim Draper and the Singapore-based longevity fund Immortal Dragons, is pitching “organ sacks” as an ethical alternative to testing drugs on living animals. These structures would contain all the typical organs, kidneys, liver, heart tissue, you name it, but without a brain, meaning they couldn’t think or feel pain. The company’s cofounder Alice Gilman emphasizes they’re not “missing” anything; they’re specifically designed to only have what’s needed for testing purposes.

Why does this matter right now? The Trump administration is phasing out animal testing across the federal government, and there’s already a shortage of research monkeys in the United States. China stopped exporting nonhuman primates in 2020, and the CDC is winding down its own monkey research. Animal rights activists have been pushing for years to end these experiments, with some federally-funded primate research facilities even considering shutting down. If another pandemic hits, scientists worry there won’t be enough research animals to test vaccines and treatments.

Organ sacks could solve this problem. Unlike existing “organs-on-chips” or tissue models that lack the full complexity of actual organs, these structures would theoretically include blood vessels and other intricate systems. Gilman says it’s already technically possible to create these in mice, and the plan is to move toward monkey versions and eventually human ones. The team is exploring stem cell technology and gene editing to make it happen, potentially using induced pluripotent stem cells, basically reprogrammed adult skin cells, that could be edited to skip brain development entirely.

But here’s where it gets even more ambitious: R3 Bio isn’t just thinking about replacing animal testing. The long-term vision is creating nonsentient human organ sacks that could provide blood, tissue, and organs to people who desperately need them. Over 100,000 Americans are currently waiting for organ transplants, and 13 people die every day on that waiting list. Gilman was inspired partly by her father’s heart transplant experience, and she’s also pointing out the massive illegal organ-harvesting trade happening globally.

Of course, this raises some serious ethical questions. Bioethicist Hank Greely from Stanford thinks it could work, but he acknowledges the “yuck factor” will be real. How would these entities look? How would they behave? What counts as consciousness anyway? These are questions society will need to wrestle with before this technology becomes reality.

Right now, R3 is still in early stages, working with monkey cells and apparently recruiting veterinarians in Puerto Rico to help with primate pregnancies. It’s all still theoretical, but the fact that serious money and serious scientists are backing this idea suggests we might actually be looking at a genuine alternative to animal testing in the not-too-distant future.