The company’s TSHA-201 AAV gene therapy for Rett syndrome is its current priority.
Taysha Gene Therapies is working on transferring deprioritized programs to collaborators, including its TSHA-120 adeno-associated virus (AAV) vector gene therapy program for giant axonal neuropathy (GAN).1
The company previously announced that it had discontinued development of TSHA-120 in September 2023 after obtaining feedback from a Type C meeting with the FDA related to the roadmap to approval for the therapy.2
Other therapies that the company has discontinued include TSHA-101, which was being investigated in people with GM2 gangliosidosis; TSHA-104 for SURF1-associated Leigh syndrome; TSHA-112 in adult polyglucosan body disease; and TSHA-118 for CLN1 Batten disease. Taysha has since pivoted to the development of its clinical stage AAV vector-based gene therapy for the treatment of Rett syndrome, TSHA-201.
Taysha announced that it would be transferring the rights to TSHA-120 to National Institute of Neurological Disorders and Stroke (NINDS); the rights to TSHA-101 to Queen’s University; and the rights to TSHA-104 and TSHA-112 back to their originating institutions. The company has also provided investigational clinical trial material for an individual-patient investigator-initiated IND request from Rush University Medical Center.1
WATCH NOW: Sukumar Nagendran, MD, on the Potential of TSHA-102 in Pediatric Patients With Rett Syndrome
“Today’s announcement demonstrates meaningful progress to advance important development work for several deprioritized programs. Creating options for these programs has been a focus since the Company completed a management change in December 2022, and the new loan and security agreement afforded the flexibility to implement certain opportunities,” Sean P. Nolan, Chairman and Chief Executive Officer, Taysha, said in a statement.1 “As we continue to focus on advancing our lead TSHA-102 program for the treatment of Rett syndrome, we are pleased that we can ensure these programs are provided to the right advocates, clinicians and scientific experts who can potentially move these programs forward for the benefit of patients.”
TSHA-120 was being evaluated in an open-label phase 1/2 clinical trial (NCT02362438). In June 2023, Taysha reported that participants treated with TSHA-120 had a 99% probability of positive treatment effect on slowing disease progression, with an estimated average treatment effect of 31% on the Modified Friedreich’s Ataxia Rating Scale and an estimated treatment effect of 28% on Motor Function Measure 32 (MFM32) Domain 3 (distal motor function –hands) compared to natural history data.3
Participants also had a 100% probability of positive treatment effect on slowing disease progression in visual acuity, as measured by Logarithm of the Minimum Angle of Resolution, with an estimated treatment effect of 70% in the right eye and 51% in the left eye.3
We believe we have made significant progress in demonstrating the therapeutic potential of TSHA-120 and identifying a potential registrational path,” Nolan said in a statement about the discontinuation.2 “Following FDA feedback, we have made the decision to discontinue further development of the program due to challenges related to the feasibility of the study designs to support a potential biologics license application (BLA) submission in this ultra-rare neurodegenerative disease. I want to express our gratitude to the patients and families who participated in the trial, the GAN community, and the National Institutes of Health for their partnership in establishing the foundation for a potential treatment option in GAN. We plan to pursue external strategic options for TSHA-120 that may enable further development of TSHA-120 and help patients with this devastating disease.”