GlaxoSmithKline and Italian partners Fondazione Telethon and Ospedale San Raffaele have submitted an application in Europe to market an investigational gene therapy for the treatment of an ultra-rare white blood cell deficiency condition often referred to as ‘bubble boy disease’.

The groups are seeking European Medicines Agency approval for the use of GSK2696273 to treat patients with adenosine deaminase severe combined immunodeficiency syndrome (ADA-SCID), for whom no suitable human stem cell donor is available.

Around 14 children in Europe are born each year with the disease, in which a faulty gene inherited from both parents stops production ADA, a protein essential for the formation of lymphocytes and a functioning immune system. 

ADA-SCID patients rarely survive beyond one to two years unless their immune function is restored. In the first instance, treatment strategies are centred on antibiotics and antifungal treatments to keep serious infections at bay, but most sufferers will ultimately need a bone marrow transplant from a matched donor. If these fail or no suitable donors are found, gene therapy could provide another option.

The submission is based on data from 18 children administered GSK2696273, the first of which was treated over thirteen years ago. Three patients needed either follow-up enzyme replacement therapy or a bone marrow transplant, but all patients are alive today, and no significant tolerability events related to the therapy have been observed thus far. 

GSK entered into a strategic pact with Fondazione Telethon, one of the biggest biomedical charities in Italy and its partner San Raffaele in 2010, gaining an exclusive licence to the gene therapy.