Allogeneic processed thymus tissue

Allogeneic processed thymus tissue, marketed as Rethymic, is a tissue-based therapy made from donor thymus tissue that is processed and cultured before being surgically implanted into a patient. It is used to treat congenital athymia, a rare pediatric condition in which children are born without a functioning thymus gland, leaving them with severely compromised immune systems. In a one-time surgical procedure, slices of the processed tissue are implanted into the quadriceps muscle, and immune reconstitution typically takes six months or longer to develop. Rethymic received United States Food and Drug Administration approval in October 2021, becoming the first thymus tissue product approved by the agency. Its safety and efficacy were established through clinical studies of 105 pediatric participants aged one month to sixteen years, followed from 1993 to 2020, which showed improved survival with most treated patients surviving at least two years.