Taysha Gene Therapies (NASDAQ:TSHA) saw its stock surge 19% after unveiling critical updates on the design of its pivotal trial for TSHA-102, a gene therapy candidate for treating Rett Syndrome. The trial plans, backed by encouraging data from Part A of the REVEAL study and informed by IRSF natural history findings, received written alignment from the FDA.
The regulatory agency has greenlit a single-arm, open-label pivotal study, where patients aged six and older will act as their own controls. The primary measure of success will be improvements in developmental milestones. The Dallas-based biotech expects to launch the trial in the third quarter of 2025.
According to the company, all participants between ages 6 and 21 in the REVEAL Part A trial showed measurable progress—each gaining at least one developmental milestone post-treatment with TSHA-102. This is a particularly meaningful result given the “near-zero likelihood” of such gains without intervention, as highlighted by the natural history dataset. Furthermore, the high-dose cohort consistently outperformed the low-dose group, with no serious side effects or dose-limiting toxicities observed.
Reacting to the news, Silvan Tuerkcan of Citizens JMP raised his price target on Taysha from $5.00 to $6.00, reiterating a Market Outperform rating. He emphasized the significance of both the FDA’s support and the measurable outcomes, stating, “The current response rate is 100%, with 2.2 milestones being met per patient vs. the 1+ required to qualify as responder. This leaves a significant margin for Part B.”
Alongside the trial update, Taysha also launched an underwritten public offering of common stock and pre-funded warrants. The company is focused on advancing AAV-based gene therapies for severe central nervous system (CNS) disorders, with TSHA-102 leading its pipeline.
The FDA advised Taysha to submit the pivotal Part B trial protocol and its statistical analysis plan (SAP) as an amendment to the existing IND, eliminating the need for a formal end-of-phase meeting. This streamlining could accelerate the study’s start, aligning with the company’s goal of initiating trial activities in Q3 2025.
With promising clinical results, regulatory momentum, and a high unmet need in Rett Syndrome, Taysha is positioned to take a major step forward in its mission to deliver transformative treatments to patients affected by rare CNS diseases.