Last July, an article was published in medical journal Blood, which described the success of a cell gene therapy modality to treat the immunodeficiency caused by adenosine deaminase deficiency – “Bubble boy” disease. This is a disease that alters purine metabolism, leading to an accumulation of metabolites that are toxic for lymphocyte development. As a result, the immune defences of these patients are much weakened, so they often suffer serious infections. It can also be associated with cognitive and hearing deficits.
Now, a group of researchers from Ospedale San Raffaele, Milan (Italy) and the Telethon Foundation, in collaboration with pharmaceutical giant GSK, have developed their product “Strimvelis”, which is the first gene therapy to use genetically modified stem cells. It is also the first product approved by the European Commission to treat the aforementioned immunodeficiency.
The medication is generated from a gene modification of the patient’s own stem cells. The defect that causes the disease is corrected in the cells, which are then injected into the patient via intravenous infusion so that they can henceforth colonise their bone marrow.
As they are genetically modified cells from the patient himself, and not from a third party, the risk of graft-versus-host disease is drastically reduced, which is clearly an unquestionable medical advantage.
Authorisation was obtained from the European Commission after assessing Strimvelis in 18 children, in whom a 3-year survival rate of 100% was found. This opens a promising path for application of this medication in patients with adenosine deaminase deficiency.
From an ethical point of view, there is no difficulty in the use of Strimvelis, provided that the necessary requisites for implementing a new cell therapy are met since the genetic modification is performed in the patient’s own adult stem cells.