HexemBio secures $10.4 million for a therapy focused on stem cell rejuvenation.

      The biotech company based in Berkeley is supporting an approach published in Nature that focuses on recreating the embryonic environment for the initial formation of blood stem cells, as opposed to chemically or genetically reprogramming aged cells. Its primary program is aimed at bone marrow transplants for blood cancers and has received FDA Orphan Drug Designation.

      HexemBio has launched with a seed round of $10.4 million, led by Draper Associates and joined by SOSV, Seraphim, and other investors. The company, located in both Berkeley and New York, is developing what it claims to be the first therapy for rejuvenating blood stem cells, centered around a platform known as the Synthetic Human Yolk Sac.

      Instead of editing or chemically reprogramming aged hematopoietic stem cells, the technology temporarily places the patient's own cells into a reconstituted version of the environment where blood stem cells develop in an embryo before they are returned via standard IV infusion.

      Hematopoietic stem cells are located deep within the bone marrow and generate all blood and immune cells in the human body. Their decline with age is associated with diminished immunity, chronic inflammation, and a heightened risk of diseases such as blood cancers and neurodegenerative conditions.

      Past efforts to reverse this decline have generally involved transcription-factor reprogramming, cytokine treatments, or gene editing, methodologies that may lead to unstable cell states or safety issues, which HexemBio claims its approach avoids.

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

      The company’s leading clinical program is aimed at bone marrow transplantation for patients suffering from blood cancers such as acute myeloid leukemia and acute lymphoblastic leukemia. HexemBio received FDA Orphan Drug Designation for this purpose in July 2025 and held its FDA Pre-IND meeting in January 2026, with first-in-human trials expected to begin in 2027.

      The regulatory strategy emphasizes outcomes related to bone marrow transplants, as aging itself is not recognized as a regulatory indication, a limitation that has influenced how several biotechs in the longevity space have structured their initial clinical programs.

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

      The advisory board includes Robert S. Langer, an Institute Professor at MIT and co-founder of Moderna, who described the approach as "fundamentally different from transcription-factor reprogramming or gene editing," adding that the initial data is "extremely compelling."

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

      Funding from the seed round will be allocated for completing IND-enabling studies and GMP manufacturing in preparation for the trial scheduled for 2027.