GSK transferred its rare disease gene therapy portfolio to Orchard Therapeutics in April 2018. In return GSK received a 19.9% equity stake plus board seat, royalties on Strimvelis (first approved ex vivo lentiviral gene therapy, for ADA-SCID), and commercial milestone payments. Portfolio includes OTL-101 (ADA-SCID), OTL-200 (MLD), OTL-300 (TDT), plus three preclinical programs from Telethon/San Raffaele. Strategically notable as one of the largest gene therapy portfolio carve-outs to date.