Taysha Gene Therapies’ treatment candidate for Rett syndrome has shown hints of efficacy in a handful of adult and pediatric patients enrolled in two early-phase clinical trials.
The treatment, dubbed TSHA-102, is one of Taysha’s few remaining candidates after the company was forced to offload some of the paused programs in its pipeline back in February after years of pressure from patient groups.
In the Phase 1/2 adult and adolescent trial, two patients given low dose TSHA-102 demonstrated “sustained and new improvements” in multiple clinical measures, including motor skills, communication and socialization and autonomic function at up to 52 weeks.
The first patient was able to sit unassisted for the first time in more than a decade. The second patient had improvements in hand stereotypies and breathing and remained seizure-free for eight and a half months with 25% lower anti-seizure medication, according to a company release.
Similar effects were seen in two subjects enrolled in a separate Phase 1/2 pediatric trial at up to 22 weeks. The first patient demonstrated improved hand function, grasp and gross motor coordination and gained visual reception and receptive language skills. The second patient was able to stand up from a chair and walk up a stair and saw an increase in the number of seizure-free days.
Tasyha also received independent data monitoring committee clearance to advance to a high-dose cohort in the pediatric study, with dosing expected to start in the third quarter.
Taysha’s share price $TSHA was down 36% at market open Tuesday.
There were no serious adverse events in the adult and adolescent trial but one of the pediatric patients experienced two SAEs, both of which were deemed unrelated to treatment.
The first SAE was a cluster of seizures and the second was serious discomfort, with both resulting in emergency room admittance, Taysha’s head of R&D Sukumar Nagendran said on a conference call Tuesday. Both events were related to underlying disease and have since resolved, Nagendran added.
TSHA-102, an AAV9-based gene therapy, is designed to deliver a functional copy of the MECP2 gene to cells in the central nervous system.