HexemBio Raises $10.4M for Stem Cell Rejuvenation Therapy
April 7, 2026 – 1:09 pm
The Berkeley biotech is backing a Nature-published approach that recreates the embryonic environment where blood stem cells first form, rather than reprogramming aged cells chemically or genetically. Its lead programme targets bone marrow transplant in blood cancers and has received FDA Orphan Drug Designation.
HexemBio has publicly launched with a $10.4 million seed round led by Draper Associates, with participation from SOSV, Seraphim, and other investors. The Berkeley and New York-based company is developing what it describes as the first blood stem cell rejuvenation therapy, built around a platform called the Synthetic Human Yolk Sac.
Rather than editing or chemically reprogramming aged haematopoietic stem cells, the technology temporarily places a patient’s own cells into a recreated version of the developmental environment where blood stem cells first emerge in the embryo, then returns them via standard IV infusion.
Haematopoietic stem cells sit deep in the bone marrow and give rise to every blood and immune cell in the human body. Their decline with age is linked to weakened immunity, chronic inflammation, and increased susceptibility to conditions including blood cancers and neurodegeneration.
Previous attempts to reverse this decline have typically involved transcription-factor reprogramming, cytokine treatments, or gene editing, approaches that can push cells into unstable states or carry safety risks. HexemBio says its method sidesteps these issues.
The Synthetic Human Yolk Sac recreates the microenvironment that generates the body’s first blood stem cells during early embryonic development. Foundational work supporting the platform was published in Nature in February 2024, by a team led by Mo Ebrahimkhani at the University of Pittsburgh, with Samira Kiani and Joshua Hislop among the authors. All three are now co-founders of HexemBio.
The company’s lead clinical programme targets bone marrow transplant in patients with blood cancers including acute myeloid leukaemia and acute lymphoblastic leukaemia. HexemBio received FDA Orphan Drug Designation for this indication in July 2025 and completed its FDA Pre-IND meeting in January 2026. First-in-human trials are targeted for 2027.
Regulatory strategy focuses on bone marrow transplant outcomes because ageing itself is not currently recognised as a regulatory indication, a constraint that has shaped how several longevity-adjacent biotechs have structured their early clinical programmes.
The founding team spans MIT, UC Berkeley, Harvard, and Y Combinator. Gabriel Levesque Tremblay, a former YC founder and UC Berkeley postdoc, serves as CEO. Samira Kiani, a Presidential Early Career Award recipient who trained at MIT, is CTO. Mo Ebrahimkhani, the inventor of the underlying technology and a pioneer in synthetic developmental biology, is CSO. Joshua Hislop, whose doctoral work contributed directly to the Nature publication, leads the company’s AI platform.