Children born with ADA-SCID do not have a fully functioning immune system and are unable to fight off common infections. The disease affects nearly 15 children a year in Europe.
Strimvelis, developed by GlaxoSmithKline (GSK) and Italian companies Fondazioine Telethon and Ospedale San Raffaele, is first corrective gene therapy for children to secure regulatory approval anywhere in the world.
Strimvelis is only administered once and does not depend on a third party donor. With this therapy, the patient’s own bone marrow cells are removed, and a normal copy of the ADA gene will be inserted into the cells using a vector.
The gene-corrected cells will then be re-introduced to the patient through an intravenous infusion, after which some of the cells come back to the bone marrow.
Patients are also pre-treated with low dose chemotherapy in order to enhance the engraftment of the gene-modified cells in their bone marrow.
The commission’s approval was based on data collected from 18 children treated with Strimvelis. All participants in the pivotal study (n=12) who received Strimvelis were alive three years post treatment.
All the children (n=18) who contributed to the data package are alive today, with a median follow-up duration of about seven years.
GSK said a significant reduction in severe infections has been documented and no leukaemic events have been observed so far.