Taysha Gene Therapies, Inc. announced that subsequent to the receipt of Type C meeting feedback from the United States (U.S.) Food and Drug Administration (FDA) regarding a registrational path for TSHA-120, the Company will discontinue the development of its TSHA-120 program in evaluation for the treatment of giant axonal neuropathy (GAN). Further, Taysha announced that Astellas Gene Therapies, Inc. (f/k/a Audentes Therapeutics, Inc. (d/b/a Astellas Gene Therapy)) (Astellas) has elected not to exercise its option to obtain an exclusive license to TSHA-120 under the Option Agreement between Astellas and Taysha. In 2022, Taysha submitted and reviewed with the FDA in a Type B end-of-Phase 2 meeting, a subset of available evidence from a Phase 1/2 clinical trial investigating TSHA-120 for the treatment of GAN, which was initiated by the NIH.

FDA feedback included the need to address the heterogeneity of disease progression in GAN and the effort-dependent nature of MFM32 as a primary endpoint in an unblinded study. To further discuss a potential regulatory path forward for TSHA-120, Taysha submitted a new comprehensive analysis of the totality of data from the natural history and interventional trial comparing functional and biological measurements against a Disease Progression Model (DPM) as part of a Type C meeting request to the FDA in June 2023. FDA Type C meeting feedback indicated that the FDA continues to recommend a randomized, double-blind, placebo-controlled trial as the optimal path to demonstrate efficacy in TSHA-120.

Among other areas of feedback, the FDA also provided a potential path for a single-arm trial with an external control group matched with to-be treated patients by multiple prognostic factors and recommended longer term follow up to account for potential bias.