Rett Syndrome Gene Therapy Granted RMAT Designation

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The FDA granted the Regenerative Medicine Advanced Therapy (RMAT) designation after reviewing the phase 1 safety and efficacy data.

This article originally appeared on CGTLive^®.

The FDA has granted Regenerative Medicine Advanced Therapy (RMAT) Designation to Taysha Gene Therapies’ TSHA-102 gene therapy program for treating Rett syndrome.¹

Gene therapies modify a person's genes to treat or cure disease.

Image credit: ipopba - stock.adobe.com

The designation comes after Taysha was cleared to escalate to the higher dose cohort early in its phase 1/2 REVEAL adolescent and adult clinical trial (NCT05606614) evaluating TSHA-102 in March 2024 by an Independent Data Monitoring Committee (IDMC).² The trial has dosed 3 participants with 5.7x10¹⁴ total vg, data from which prompted the FDA to grant the RMAT designation.

“We believe receiving RMAT designation reinforces the high unmet medical need in Rett syndrome and the therapeutic potential of TSHA-102 to change the treatment paradigm,” Sukumar Nagendran, MD, president and Head of R&D, Taysha, said in a statement.¹ “Importantly, RMAT designation was granted following the FDA’s review of safety and efficacy data from the first 3 patients dosed with the low dose of TSHA-102 across both of our REVEAL Phase 1/2 trials. We believe this important recognition from the FDA further supports the potential of our gene therapy candidate to bring meaningful change to patients and families living with Rett syndrome.”

The RMAT designation was created as part of the 21st Century Cures Act to speed up the development of therapies intended to treat, modify, reverse, or cure serious or life-threatening diseases or conditions.³ In addition, the drug has the potential to address unmet needs for these diseases and conditions.

More data from the trial are expected to be presented in the second half of 2024. Taysha also plans to extend the study, which began in Canada, into the United States, and has submitted the adolescent and adult (age 12+ years) trial protocol to the FDA.

“We remain focused on advancing the development TSHA-102 to bring a potentially disease-modifying therapy being evaluated to address the genetic root cause of Rett syndrome to all patients and families living with this devastating disease. Receiving RMAT designation helps facilitate this goal by enabling increased dialogue with the FDA to expedite our development plan for TSHA-102. We look forward to working closely with the FDA and other regulatory agencies as we continue to advance our TSHA-102 program,” Rumana Haque-Ahmed, Chief Regulatory Officer of Taysha, added.¹

TSHA-102 is an intrathecally delivered AAV9 investigational gene therapy that delivers the MECP2 gene to cells in the central nervous system. It is also being evaluated in a separate phase 1/2 REVEAL Pediatric Study clinical trial (NCT06152237) in the United States and United Kingdom.

“We have been quite encouraged by the initial safety and efficacy data demonstrated to date with TSHA-102 and are pleased that we are cleared to dose the second patient in our REVEAL phase 1/2 pediatric trial, and importantly, that the IDMC approved our request to proceed to dose escalation in our REVEAL phase 1/2 adolescent and adult trial earlier than planned,” Sean P. Nolan, the chairman and chief executive officer of Taysha, said in an earlier statement.² “Advancing to the high dose cohort accelerates our ability to further inform our clinical development and regulatory plan for Part B of the study by at least a quarter. Additionally, we believe expanding our ongoing REVEAL adolescent and adult trial in Canada into the US will further support our goal to evaluate TSHA-102 across a broad range of ages and stages of patients with Rett syndrome. We are pleased with the progress we’ve made and remain focused on evaluating TSHA-102 as a potential treatment option for patients and families living with Rett syndrome.”

The gene therapy remains Taysha’s only lead candidate after the company scrapped the majority of its pipeline in 2023, including programs for giant axonal neuropathy, SURF1-associated Leigh syndrome, adult polyglucosan body disease, and CLN1 Batten disease., Taysha recently announced that rights to these programs would be returned to its collaborators.⁴