TSHA-102

A one-time gene therapy delivered into the spinal fluid that provides a working MECP2 gene with built-in cell-level regulation. Uses miRNA technology to let each cell control its own MECP2 levels. Has FDA Breakthrough Therapy, Fast Track, and Rare Pediatric Disease designations.

TSHA-102 delivers a functional MECP2 gene using an AAV9 virus injected into the spinal fluid. Its unique miRARE technology lets each individual cell regulate how much MECP2 protein it makes, preventing the dangerous overexpression that can occur with standard gene therapy approaches. This cell-by-cell control is designed to restore normal MECP2 levels safely.

Clinical trials have reported no treatment-related serious adverse events. The intrathecal delivery route (spinal injection) carries standard procedural risks. Long-term safety monitoring is ongoing for all treated patients.

Delivered as a single intrathecal injection (into the spinal fluid via lumbar puncture). This is a one-time treatment that does not require surgery. Both pediatric (ages 2-17) and adult (18+) patients are being studied.

TSHA-102 is currently in phase 2 clinical trials for Rett Syndrome. It has not yet received FDA approval.

miRARE (miRNA-Responsive Auto-Regulatory Element) is Taysha Gene Therapies' technology for controlling MECP2 gene expression at the individual cell level. Each cell contains natural microRNAs (miRNAs) that reflect its current MECP2 status. The miRARE element in TSHA-102 responds to these miRNA signals: in cells that already have enough MECP2, the miRARE system dials down production from the delivered gene, preventing dangerous overexpression. In cells that need more MECP2, production continues. This provides cell-by-cell tailored regulation.

The REVEAL trial showed a 100% response rate on the primary endpoint: every treated patient gained or regained at least one developmental milestone. Improvements were seen across motor skills, communication, and seizure reduction. Based on natural history comparisons, this response rate had less than a 6.7% chance of occurring without treatment. No treatment-related serious adverse events were reported.

TSHA-102 is delivered as a single intrathecal injection (lumbar puncture into the spinal fluid). This is less invasive than the intracerebroventricular injection used by NGN-401, as it does not require neurosurgery. The intrathecal route allows the AAV9 vector to distribute throughout the cerebrospinal fluid and reach brain cells. Both pediatric and adult patients have been treated in the REVEAL trial.

Yes. The REVEAL trial enrolled both adults (18+) and children (ages 2-17), making TSHA-102 one of the few Rett therapies being tested across the full age range. Adult patients with Rett syndrome often have significant unmet treatment needs, and the inclusion of adults in the trial provides important data for this population.

No. TSHA-102 is in clinical trials and has not been approved by the FDA. Dosing in the REVEAL pivotal trial finished in June 2026, and topline data are expected in the first half of 2027. Taysha Gene Therapies received Breakthrough Therapy Designation in October 2025, which may accelerate the regulatory review process. Families interested in enrollment should discuss eligibility with their neurologist.