Taysha: Gene Therapy Boosts Motor Skills in Rett Study

Taysha Gene Therapies has released new data on its gene therapy for Rett syndrome, showcasing significant improvements in both adults and children treated with low doses of their therapeutic candidate, TSHA-102. The Dallas-based biotech company has extended the follow-up data on two adult patients and provided initial findings on two pediatric patients.

The first adult, a 20-year-old female who had lost the ability to walk and sit unassisted at the age of eight, showed remarkable progress after 52 weeks of treatment with TSHA-102. This patient regained the ability to sit unassisted and move her legs. According to Sukumar Nagendran, M.D., Taysha’s head of R&D, there were notable improvements in motor skills. "She could open her hands, dissociate her fingers, scratch her nose and touch a screen following treatment,” Nagendran reported. These sustained motor skill improvements are typically not seen in the natural progression of Rett syndrome, indicating the potential of TSHA-102 to provide meaningful benefits to both patients and their caregivers.

This patient also showed enhanced social interest, improved vocalization, and for the first time in 20 years, was able to sleep through the night. Additionally, her seizure events remained stable on reduced levels of anti-seizure medication compared to her baseline.

The second adult patient, a 21-year-old female with a milder form of Rett syndrome, exhibited improvements within 25 weeks of treatment. This patient had better motor skills at the beginning of the study compared to the first subject. Post-treatment, she showed enhanced hand stereotypies, better posture, improved stability, heightened social interest, and better breathing patterns. These improvements were seen for the first time since she regressed at the age of three.

In addition to the adults, Taysha presented initial data on two children aged six and seven years. Both children were at an earlier stage of disease progression at the time of their treatment. Taysha reported efficacy data from eight weeks post-treatment for one child and 12 weeks for the other. Early signs of improvement included better hand function and improved breathing patterns. Notably, the child with 12 weeks of follow-up gained the ability to identify objects from memory and follow two unrelated commands.

Rett syndrome patients exhibit a wide range of genetic backgrounds, resulting in varying symptoms and levels of severity. Taysha's CEO Sean Nolan highlighted the broad potential of TSHA-102 for treating different Rett patients, regardless of their genetic mutations or initial severity of their condition. "The patients dosed with TSHA-102 across both trials have different genetic mutations and associated disease severity, ranging from mild to severe,” Nolan explained. He believes that the consistent improvements observed across diverse clinical domains support the broad treatment potential of TSHA-102.

In response to these promising results, Taysha is expanding its trials. The company has reduced the minimum age requirement for the adolescent and adult study to 12 years and is planning to escalate to a higher dose. In the pediatric study, Taysha aims to move to a higher dose once initial safety data from the adolescent and adult trials are available, which is expected in the third quarter.

Taysha is at the forefront of developing a gene therapy for Rett syndrome, with other companies like Neurogene and Alcyone Therapeutics also working on potential treatments. Neurogene has a candidate currently in clinical trials and plans to release preliminary data this year, while Alcyone Therapeutics' candidate is still in preclinical development.