Taysha Gene Therapies provides updates for programs TSHA-120, TSHA-102

Taysha Gene Therapies announced new data analyses for TSHA-120 in GAN and initial clinical observations for TSHA-102 in Rett syndrome. Taysha will host a virtual R&D Day today at 10:00 AM ET to discuss these updates. Key R&D Day Highlights: TSHA-120: New comprehensive data analysis enabled the development of a DPM using all available data from the largest existing GAN natural history database. Relatively stable to improved sensory response amplitudes observed on nerve conduction studies, in conjunction with increased regenerative clusters on nerve biopsy, suggest sensory nerve or neuron regeneration in a progressive neurodegenerative disease. Using natural history data as an external control, Bayesian analysis demonstrated a clinically meaningful treatment effect of TSHA-120: Functional endpoints: Modified Friedreich’s Ataxia Rating Scale demonstrated a 99% probability of positive treatment effect on slowing disease progression, with an estimated average treatment effect of 31%; Motor Function Measure 32 Domain 3 demonstrated a 99% probability of positive treatment effect on slowing disease progression, with an estimated treatment effect of 28%; Visual Acuity,as measured by Logarithm of the Minimum Angle of Resolution, demonstrated 100% probability of positive treatment effect on slowing disease progression. Electrophysiological endpoints: Analysis demonstrated a 100%probability of positive treatment effect on slowing disease progression; Compound Muscle Action Potential demonstrated a 94% probability of positive treatment effect on slowing disease progression. Biological Endpoints: 4 out of the 5 patients that had stabilization or improvements in SNAPs had increased regenerative clusters on nerve biopsy . Skin biopsy-nerve fiber density: 5 patients saw stabilization or increases in nerve fiber density of the skin in at least one location of the proximal or distal leg at month 12, including 3/3 in the high-dose and one in the medium-high dose. Over seven years of long-term clinical data support the safety and tolerability profile of TSHA-120. TSHA-102: First patient has been dosed in the REVEAL Phase 1/2 trial in adult patients with Rett syndrome; The patient was discharged from the hospital and has completed multiple follow-up visits, per the study protocol; Second potential patient has been identified and will undergo screening if all protocol defined criteria are met; dosing expected to proceed pending IDMC review of available clinical data from the first patient; CTA submission to UK MHRA in pediatric patients anticipated in mid-2023; IND application submission to U.S. FDA expected in the second half of 2023