GSK publishes long-term safety and efficacy data for ADA-SCID gene therapy

GSK plc, in collaboration with Fondazione Telethon and Ospedale San Raffaele, has published long-term safety and efficacy data for a gene therapy targeting children with ADA-SCID (adenosine deaminase deficiency), a severe form of combined immunodeficiency.

The study, detailed in the journal BLOOD, analyzed outcomes for 18 children treated between 2000 and 2010 at the San Raffaele Telethon Institute for Gene Therapy (SR-Tiget). ADA-SCID is a rare inherited disorder that prevents the development of a healthy immune system, often proving fatal within the first year of life.

Results showed all 18 patients were alive at a median follow-up of 6.9 years. The majority experienced immune reconstitution within six months post-treatment. Furthermore, 83% of patients did not require further interventions such as stem cell transplants or enzyme replacement therapy after gene therapy. The incidence of severe infections significantly decreased following treatment compared to the pre-treatment period.

According to the report, 12 of 14 surveyed patients (86%) were attending school at an age-appropriate level. Researchers highlighted that this gene therapy, now known as Strimvelis™, offers an alternative for children lacking a matched donor for stem cell transplants, reducing risks of complications like graft-versus-host disease (GvHD).

Reported adverse events were consistent with those expected for ADA-SCID patients undergoing low-dose chemotherapy and immune recovery. Common events included standard childhood infections. Among serious adverse events, infections were most frequent, often linked to the central venous catheters used during treatment. No cases of leukemia have been observed to date.