Taysha Gene Therapies announced positive clinical data from Part A of its REVEAL trials for TSHA-102 in Rett syndrome, along with FDA alignment on a pivotal Part B trial design. The FDA’s agreement on a single-arm, open-label pivotal trial was based on natural history data showing minimal likelihood of developmental milestone gain after age six, contrasted with TSHA-102 trial data showing a 100% responder rate in patients aged 6-21. The primary endpoint of the pivotal trial will be developmental milestone gain or regain in patients six years and older, a significant step toward potential regulatory approval.
This news is crucial because it indicates a potential shift in Rett syndrome treatment. Current therapies are primarily focused on managing symptoms, while TSHA-102 targets the underlying genetic cause. The observed milestone gains, even in older patients previously considered to be in a developmental plateau, suggest a potential for meaningful functional improvements not seen with existing treatments. This advancement offers hope for a disease-modifying therapy, potentially improving patients’ quality of life and long-term outcomes.
Analysis of natural history data from over 1,100 patients showed that after the age of six, the chance of gaining or regaining developmental milestones is exceptionally low. In contrast, Part A of the REVEAL trial saw all 10 patients treated with TSHA-102 gain at least one milestone, with a total of 22 milestones gained across the group. The higher dose group demonstrated a faster response rate, indicating a dose-dependent effect. Importantly, both high and low doses were well-tolerated with no serious adverse events or dose-limiting toxicities. The pivotal Part B trial will enroll approximately 15 patients aged six and older and is anticipated to begin in Q3 2025.
This positive clinical data and FDA alignment positions TSHA-102 as a leading candidate for Rett syndrome treatment. A successful pivotal trial could lead to the first disease-modifying therapy for this debilitating disorder, significantly impacting the lives of patients and their families. The results also suggest a potential paradigm shift in the field, prompting further research into gene therapies for other neurodevelopmental disorders.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
