FDA Approves Rethymic for Pediatric Congenital Athymia

Enzyvant’s Rethymic is the first FDA approved treatment for congenital athymia.

Enzyvant, a subsidiary of Sumitovant Biopharma, announced that FDA has approved Rethymic (allogeneic processed thymus tissue-agdc) for the treatment of pediatric patients with congenital athymia on Oct. 8th, 2021. According to a company press release, Rethymic is the first and only FDA-approved treatment for immune reconstitution of congenital athymia. Enzyvant has obtained a priority review voucher for Rethymic under the Rare Pediatric Disease Program.

Congenital athymia is a rare condition, with approximately 17–24 new cases occurring each year. Children with congenital athymia are born without a thymus, resulting in depleted T-cells, severe immunodeficiency, and immune dysregulation. Without supportive care, patients typically die by age two or three.

Rethymic is engineered human thymus tissue that is designed to regenerate the thymic function in children with the condition. This is intended to induce a robust immune response that patient’s bodies cannot naturally produce. Notably, Rethymic does not require donor-recipient matching.

Ten studies, involving 105 patients who were surgically implanted with Rethymic, occurred from 1993 to 2020. Of these patients, 29 died, with 23 deaths occurring within a year of implantation. For patients who were alive at one year post implantation, the estimated long-term survival rate was 94% at a median follow-up time of 10.7 years.

Researchers found that T-cells began to reconstitute over the first year, with a durable increase through year two. There was also a statistically significant reduction in the number of infections over the first two years after treatment.

“For too long, families have faced a reality that the brutal journey for pediatric congenital athymia patients receiving supportive care only would end tragically. The FDA approval of Rethymic will help patients access this desperately needed therapy beyond clinical study,” said Rachelle Jacques, CEO of Enzyvant, in the press release. “We are deeply grateful to the 105 patients who participated in clinical trials, their families, and all of the stakeholders who contributed to this pioneering regenerative medicine research program.”

Source: Enzyvant