Who was the first patient who was given gene therapy? Why was the given treatment recurrent in nature?

The first patient who was given gene therapy was a four-year-old with adenosine deaminase (ADA) deficiency. The adenosine deaminase (ADA) deficiency is cured by growing lymphocytes outside the body of the patient in a cell culture and using a functional ADA complementary DNA (i.e., cDNA) in those lymphocytes. The treatment is recurrent because these ADA cDNA are not immortal.

Thus, this treatment is required to be repeated for new cells and cure the adenosine deaminase (ADA) deficiency.