Lentiviral haematopoietic stem-cell gene therapy for early-onset metachromatic leukodystrophy:long-term results from a non-randomised,open-label,phase 1/2 trial and expanded access

Background:Effective treatment for metachromatic leukodystrophy(MLD)remains a substantial unmet medical need.In this study we investigated the safety and efficacy of atidarsagene autotemcel(arsa-cel)in patients with MLD.Methods:This study is an integrated analysis of results from a prospective,non-randomised,phase 1/2 clinical study and expanded-access frameworks.29 paediatric patients with pre-symptomatic or early-symptomatic early-onset MLD with biochemical and molecular confirmation of diagnosis were treated with arsa-cel,a gene therapy containing an autologous haematopoietic stem and progenitor cell(HSPC)population transduced ex vivo with a lentiviral vector encoding human arylsulfatase A(ARSA)cDNA.