This was a single-arm,multicenter,open-label phase I trial.Lentiviral vectors(LV)carrying the ABCD1 gene(LV-ABCD1)was directly injected into the brain of patients with childhood cerebral adrenoleukodystrophy(CCALD),and multi-site injection was performed.The injection dose increased from 200 to 1600 lL(vector titer:1×10^(9) transduction units per mL(TU/mL)),and the average dose per kilogram body weight ranges from 8 to 63.6 lL/kg.The primary endpoint was safety,dose-exploration and immunogenicity and the secondary endpoint was initial evaluation of efficacy and the expression of ABCD1 protein.A total of 7 patients participated in this phase I study and were followed for 1 year.No injectionrelated serious adverse event or death occurred.Common adverse events associated with the injection were irritability(71%,5/7)and fever(37.2-38.5℃,57%,4/7).Adverse events were mild and selflimited,or resolved within 3 d of symptomatic treatment.The maximal tolerable dose is 1600 lL.In 5 cases(83.3%,5/6),no lentivirus associated antibodies were detected.The overall survival at 1-year was 100%.The ABCD1 protein expression was detected in neutrophils,monocytes and lymphocytes.This study suggests that the intracerebral injection of LV-ABCD1 for CCALD is safe and can achieve successful LV transduction in vivo;even the maximal dose did not increase the risk of adverse events.Furthermore,the direct LV-ABCD1 injection displayed low immunogenicity.In addition,the effectiveness of intracerebral LV-ABCD1 injection has been preliminarily demonstrated while further investigation is needed.This study has been registered in the Chinese Clinical Trial Registry(https://www.chictr.org.cn/,registration number:ChiCTR1900026649).
