The first human clinical trial of a gene therapy explicitly designed to reverse biological aging has 2, marking a historic moment for the longevity field. Sponsored by Rejuvenate Bio, the trial tests a combination approach targeting multiple aging pathways simultaneously.
The Phase 1 trial, 1 on ClinicalTrials.gov, will evaluate safety and early efficacy signals in 45 adults aged 65-85 with mild to moderate age-related functional decline. Initial results are expected within 18 months.
The Multi-Gene Approach
Rather than targeting a single gene, Rejuvenate Bio therapy delivers three genes shown in animal studies to combat aging. TERT (telomerase) extends telomeres, the protective caps on chromosomes that shorten with age. Follistatin promotes muscle growth and counters age-related sarcopenia. And Klotho is a longevity-associated protein that declines with age and is linked to cognitive function. The genes are delivered via AAV (adeno-associated virus) vectors, the same technology used in FDA-approved gene therapies for genetic diseases.
Preclinical Foundation
The approach builds on remarkable animal data. In mice, the combination therapy extended median lifespan by 41% and showed reversal of age-related changes in multiple organ systems. Treated aged mice showed improvements in cardiac function and exercise capacity, cognitive performance on memory tests, kidney function, muscle mass and strength, and metabolic health markers. In 2019, Rejuvenate Bio founder George Church made headlines by testing a similar approach in his pet dogs, reporting improved heart function and activity levels.
Trial Design
The Phase 1 trial prioritizes safety but will collect extensive biomarker data. The primary endpoint is safety and tolerability over 12 months. Secondary endpoints include changes in epigenetic age clocks, telomere length, and frailty indices. Exploratory endpoints cover organ-specific functional measures, inflammatory markers, and metabolomics. Participants will receive a single IV infusion and be monitored closely with regular blood draws, imaging, and functional assessments.
Regulatory Landscape
This trial represents a shift in how the FDA views aging. Historically, aging itself was not considered a disease and therefore not a valid drug target. Recent advocacy from researchers and the American Federation for Aging Research has helped shift this perspective. The trial is conducted under an IND (Investigational New Drug) application, putting it on a standard path toward potential approval as a treatment for age-related decline.
