$12M grant will back first trial of stem cell therapy for Huntington’s
US researcher to lead first-in-human study, expected to launch in 2026
The California Institute for Regenerative Medicine (CIRM) — a state agency created to advance novel treatments for serious medical conditions — has granted nearly $12 million in funding to support a first-in-human clinical trial that will test a stem cell therapy candidate for Huntington’s disease.
The grant was awarded to Leslie M. Thompson, PhD, a professor and the codirector of the Sue & Bill Gross Stem Cell Research Center at the University of California, Irvine. Thompson will be the principal investigator of the Phase 1b/2a trial, which has already been a green light by the U.S. Food and Drug Administration.
The trial is expected to launch in mid-2026 and enroll people with early-stage Huntington’s, according to university press release announcing the CIRM grant.
“This trial is an exciting step for regenerative medicine and its potential to change the course of Huntington’s disease. It provides additional hope to patients and families who currently have very few options,” Thompson said, adding that the award “is the culmination of a tremendous effort from a team of investigators” from UC Irvine and the University of California, Davis.
A genetic disorder, Huntington’s results from the production of a mutant form of the huntingtin protein, which forms toxic clumps and ultimately causes nerve cells in the brain to sicken and die. This leads to progressive symptoms that typically include movement problems, difficulty thinking, and behavioral challenges.
Trial to test hNSC-01, a neural stem cell therapy, in early-stage Huntington’s
The upcoming study will test a neural stem cell product dubbed hNSC-01. Neural stem cells are able to grow into many types of brain cells, including new nerve cells.
hNSC-01, which uses stem cells derived from human embryos, aims to provide new nerve cells that can replace lost ones in the brain, helping to restore normal brain signaling. The therapeutic cells also secrete signaling molecules that may help protect existing brain cells from damage.
Through these mechanisms, the experimental cell therapy is expected to slow the progression of Huntington’s, allowing patients to retain better independent functionality for longer.
In mouse models of the disease, hNSC-01 has been shown to support brain cell growth. It also was seen to potentially form connections with existing brain cells, to lower levels of mutant huntingtin protein, and to lessen behavioral and molecular abnormalities. Further, the therapy was found safe in nonhuman primates.
The new trial will be the first to test embryo-derived stem cells in people with Huntington’s, according to the researchers. Its main goal will be to assess the safety of this experimental therapeutic strategy.
A total of 21 people with early-stage Huntington’s are expected to be enrolled. In the Phase 1b portion of the trial, 12 participants will receive treatment with hNSC-01 at various doses. Based on the findings from those first participants, the trial’s Phase 2a portion will test an optimal dose of the cell therapy in an additional nine patients.
The cells will be delivered directly into the brain via a surgical procedure, and participants will then undergo close monitoring for safety and signs of potential therapeutic benefit.
The award was granted under CIRM’s Clinical Trial Stage Projects, a program designed to speed the translation of promising stem cell therapies from late-stage lab development into clinical trials to meet crucial unmet medical needs.
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