OpenAI CEO Sam Altman is doubling down on Retro Biosciences, a biotech startup based in San Francisco that wants humans to live 10 years longer than what it calls a healthy human lifespan.

Altman previously provided Retro Biosciences’ entire seed round of $180 million. Now, the startup is raising a $1 billion Series A that Altman is joining, the Financial Times reports.

Retro Biosciences, which says it plans to launch trials for drugs targeting diseases like Alzheimer’s, recently trained a model with OpenAI to turn regular cells into stem cells.

CEO Joe Betts-LaCroix told the FT he wants to move fast by discovering and developing a drug “in the 2020s.”

The startup joins other major billionaire-backed longevity efforts, including Altos Labs, which launched with $3 billion in 2022 backed by Jeff Bezos, and Unity Biotechnology, supported by both Bezos and Peter Thiel.