Orchard Therapeutics announced the U.S. Food and Drug Administration (FDA) has cleared its Investigational New Drug (IND) application for OTL-203, a hematopoietic stem cell (HSC) gene therapy being developed for the treatment of the Hurler subtype of mucopolysaccharidosis type I (MPS-IH). The company expects to initiate a global registrational trial evaluating the efficacy and safety of OTL-203 compared to standard of care in the second half of 2023. The study is a multi-center, randomized, active controlled clinical trial designed to evaluate the efficacy and safety of OTL-203 in patients with MPS-IH compared to standard of care with allogeneic hematopoietic stem cell transplant (HSCT).

A total of 40 patients with a confirmed diagnosis of MPS-IH who meet the study inclusion criteria will be randomized 1:1 to receive either OTL-203 or allogeneic HSCT. The study is powered to demonstrate superiority of OTL-203 over HSCT. The primary endpoint, which will be measured at two years post-treatment, comprises a composite of clinically meaningful outcomes, including death, the need for rescue treatment, treatment failure, immunological complications, as well as severe cognitive and growth impairment.

Secondary endpoints include biochemical markers, additional clinical assessments, as well as safety and tolerability. The company expects to open up to six sites in the United States and Europe.