Disclosed are methods for transient co-administration of rapamycin together with a gene therapy vector encoding a transgene. The present invention is directed to inhibiting the immune response of a host to the administered gene therapy vector and encoded trans gene product, thus allowing persistent trans gene expression and repeated administration of the gene therapy product to the host. The present invention is also of relevance in genetic disease patients that mount immune responses to protein replacement therapies in which case the present invention provides for transient co-administration of rapamycin together with protein replacement therapy. In a further aspect of the invention, co-administration of rapamycin could inhibit a secondary immune response in a host that has been pre-immunized with the gene therapy vector or pre-immunized with the protein product encoded by the transgene.