Cell therapy weekly: Breakthrough Therapy designation for Retts syndrome gene therapy
This week: Taysha Gene Therapies (TX, USA) has secured a US Food and Drug Administration (FDA; MD, USA) Breakthrough Therapy designation for TSHA-102 and finalized its REVEAL trial protocol. PromoCell (Heidelberg, Germany) has announced that it will launch Custom GMP Cell Culture Media Services at the 32nd ESGCT Congress (Seville, Spain; 7–10 October 2025), while CRISPR Therapeutics (Zug, Switzerland) will also share preclinical data on its SyNTase technology for Alpha-1 Antitrypsin Deficiency (AATD) at the congress.
The news highlights:
- FDA Breakthrough Therapy designation for Retts syndrome gene therapy
- Custom GMP cell culture media services
- Preclinical data on gene editing technology for AATTD to be presented at ESGCT
FDA Breakthrough Therapy designation for Retts syndrome gene therapy
Taysha Gene Therapies, a clinical-stage biotechnology company, has announced that the FDA has granted Breakthrough Therapy designation to TSHA-102, an AAV9-based gene therapy for the treatment of Rett syndrome. Rett syndrome is a rare genetic condition caused by mutations in an X-linked gene, leading to severe neurodevelopmental challenges. Patients often experience developmental regression, loss of motor and communication skills, respiratory difficulties, seizures and a reduced life expectancy.
Rumana Haque-Ahmed, Chief Regulatory Officer at Taysha, emphasized the significance of this milestone:
“The disease burden in Rett syndrome continues to be significant, and we are encouraged by the potential of TSHA-102 to address its underlying cause. We look forward to continued collaboration with the FDA as we advance toward potential registration.”
In addition to receiving Breakthrough Therapy designation, Taysha has finalized alignment with the FDA on the pivotal trial protocol and statistical analysis plan for the REVEAL study. Sukumar Nagendran, President and Head of R&D at Taysha, shared his thoughts on the progress:
“We are pleased to have finalized alignment with the FDA on our pivotal trial protocol and SAP, including the 6-month interim analysis that has potential to expedite our BLA submission for TSHA-102 by at least two full quarters…This regulatory progress reinforces our BLA readiness and allows us to focus on execution. We remain on track to initiate patient enrollment for our REVEAL pivotal trial in the fourth quarter of 2025.”
The REVEAL pivotal trial will evaluate the efficacy of a single intrathecal administration of high-dose TSHA-102 in 15 female patients aged 6 to under 22 years within the developmental plateau population of Rett syndrome. The primary endpoint will measure the gain or regain of developmental milestones across core functional domains, including communication, fine motor and gross motor skills.
Custom GMP cell culture media services
PromoCell is set to present its innovative Custom GMP Cell Culture Media Services at this years’ ESGCT. These services are designed to support clinical workflows and manufacturing processes within the cell-based therapy sector.
“We noticed an increasing demand for advanced cell culture media in regenerative medicine and cell-based therapy, and we are thrilled to introduce our GMP cell culture medium service portfolio to the life science community at the ESGCT Congress,” said Irma Börcsök, CEO of PromoCell. “This launch is a testament to our dedication to supporting customers with our long-standing cell culture medium expertise every step of the way, from discovery to preclinical, clinical, and commercial manufacturing. With both off-the-shelf and customized Excipient GMP-grade solutions now available, we’re delivering service-driven offerings that meet high regulatory standards, empowering scientists to scale their innovations with confidence and compliance.”
Attendees can visit PromoCell at Booth A35 during the ESGCT Congress to learn more about their GMP offerings and tailored solutions for research and clinical applications.
Preclinical data on gene editing technology for AATTD to be presented at ESGCT
At the ESGCT 2025, CRISPR Therapeutics will showcase preclinical findings on its innovative SyNTase gene editing platform. The presentation will focus on how this technology enables single-dose in vivo gene correction to address AATD, a rare genetic condition. AATD is a rare genetic disorder that can cause lung and liver damage due to insufficient or dysfunctional production of alpha-1 antitrypsin.
SyNTase technology integrates compact Cas9 proteins with a newly engineered class of polymerases, designed to enhance the precision and efficiency of gene editing. This approach also facilitates scalable production, making it suitable for broader therapeutic applications. Preclinical studies demonstrate the potential of SyNTase editing as a leading therapeutic approach for correcting the genetic basis of AATD. These findings also highlight the platform’s versatility in addressing other monogenic diseases.