A systematic review comparing allogeneic hematopoietic stem cell transplant to gene therapy in sickle cell disease.

INTRODUCTION:Allogeneic hematopoietic stem cell transplant (HSCT) and gene therapy (GT) are two potentially curative approaches for sickle cell disease (SCD), but they have never been compared in clinical trials. OBJECTIVE:To compare the safety and efficacy of HSCT and GT to assist clinicians and patients in making informed treatment decisions. METHODS:Phase I-III clinical trials and case reports/series were included. Regimens included HSCT from all stem cell sources, lentiviral gene therapy, and gene editing, with any conditioning regimen. We searched Medline and EMBASE databases as of 1st June 2020 for studies reporting HSCT and GT outcomes in SCD. The Newcastle-Ottawa scale was used to assess the risk of bias. Descriptive statistics and post-hoc imputation for standard deviations of mean change in FEV1 and FVC were performed. RESULTS:In total, 56 studies (HSCT, nnnnDISCUSSION:Reporting of SCD-related complications and patient-important outcomes is lacking for both strategies. We advocate for standardized reporting to better compare outcomes within and between treatment groups.