Treatment of ADA-SCID

The first stages of treatment and precautions are the same as in all forms
of SCID. 

However, in contrast to other forms of SCID, it is possible to replace the missing enzyme using a medication known as PEG-ADA. This is often referred to as enzyme replacement therapy. It is given as a weekly injection into a muscle, for instance, the thigh muscle.

PEG-ADA treatment corrects the ADA and adenosine levels in the blood, and usually leads to gradual improvement and partial correction of immune function.
It can be used until a more definitive therapy is available, such as haematopoietic
stem cell transplant (HSCT) or gene therapy.

Clinical trials of gene therapy for ADA deficiency are ongoing in Europe and the USA, with Great Ormond Street Hospital being one of the centres where this treatment is available.

A related, commercial gene therapy treatment called Strimvelis has been recently approved by NICE and is available to families as an alternative treatment in Milan. The differences between these different gene therapy options will be discussed with the families in detail. The choice between HSCT or gene therapy will depend on whether there are well-matched donors available for transplant and will be discussed at length between the parents and the transplant and gene therapy teams.

Reviewed February 2018