HexemBio secures $10.4 million for a stem cell rejuvenation treatment.

      The Berkeley-based biotech company is supporting an approach published in Nature that replicates the embryonic environment where blood stem cells initially develop, instead of chemically or genetically reprogramming old cells. Its primary program aims at bone marrow transplants for blood cancers and has been awarded FDA Orphan Drug Designation.

      HexemBio has officially launched with a seed funding round of $10.4 million led by Draper Associates, with contributions from SOSV, Seraphim, and other investors. This company, located in Berkeley and New York, is creating what it claims is the first rejuvenation therapy for blood stem cells, based on a platform known as the Synthetic Human Yolk Sac.

      Instead of editing or chemically reprogramming aged hematopoietic stem cells, the technology temporarily introduces a patient's own cells into a reconstructed version of the environment where blood stem cells first appear in the embryo, and then they are reintroduced via standard IV infusion.

      Hematopoietic stem cells, which reside deep within the bone marrow, are responsible for producing all blood and immune cells in the human body. Their decline with age is associated with weakened immunity, chronic inflammation, and an increased risk of conditions like blood cancers and neurodegeneration.

      Past efforts to reverse this decline have typically relied on transcription-factor reprogramming, cytokine therapies, or gene editing, methods that can lead to unstable cellular states or involve safety risks, which HexemBio claims to avoid.

      The Synthetic Human Yolk Sac mimics the microenvironment that produces the body's initial blood stem cells during early embryonic growth. Foundational research supporting this platform was published in Nature in February 2024 by a team led by Mo Ebrahimkhani at the University of Pittsburgh, including Samira Kiani and Joshua Hislop as authors. All three are now co-founders of HexemBio.

      The company’s main clinical program aims at bone marrow transplants for patients with blood cancers such as acute myeloid leukemia and acute lymphoblastic leukemia. HexemBio received FDA Orphan Drug Designation for this purpose in July 2025 and has concluded its FDA Pre-IND meeting in January 2026, with first-in-human trials scheduled for 2027.

      The regulatory strategy concentrates on the outcomes of bone marrow transplants, as aging itself is not currently recognized as a regulatory indication, a limitation that has influenced how various longevity-related biotech companies have formulated their early clinical programs.

      The founding team includes members from MIT, UC Berkeley, Harvard, and Y Combinator. Gabriel Levesque Tremblay, a former YC founder and postdoctoral researcher at UC Berkeley, serves as CEO. Samira Kiani, a Presidential Early Career Award recipient trained at MIT, is the CTO. Mo Ebrahimkhani, the creator of the core technology and a pioneer in synthetic developmental biology, holds the CSO position. Joshua Hislop, whose doctoral research contributed directly to the Nature publication, heads the company’s AI platform, which incorporates unique tools called YolkGPT and YolkScore. Samet Yildirim, a former YC founder with drug development expertise at Boehringer Ingelheim, is the chief business officer.

      The advisory board features Robert S. Langer, Institute Professor at MIT and co-founder of Moderna, who described the approach as “fundamentally different from transcription-factor reprogramming or gene editing” and remarked that the early data were “extremely compelling.”

      Additional advisors include Peter Barton Hutt, former chief counsel of the FDA and current board member of Moderna; Joanne Kurtzberg of Duke University, a leading bone marrow transplant clinician in the US; David Harris, founder of the first public cord blood bank in the US; Felipe Sierra, former director of the Division of Aging Biology at the NIH; Jens Nielsen, CEO of the BioInnovation Institute; and George Church, professor of genetics at Harvard Medical School and co-founder of Colossal Biosciences.

      Seed funds will be utilized to complete IND-enabling studies and GMP manufacturing in preparation for the trials set for 2027.