Longitudinal biomarker evaluation in Fabry disease patients receiving lentivirus-mediated gene therapy

Abstract

Aim: In 2016, a team of Canadian researchers initiated the world’s first gene therapy clinical trial for Fabry disease. The study, aiming to determine the safety and toxicity of lentivirus α-galactosidase A transduced autologous CD34+ cells in adult males with Fabry disease (n = 5), was conducted at three Canadian centers. The objective of the present work was to evaluate a profile of Fabry disease-related biomarkers in five participants during a 5-year surveillance period, as part of the evaluation of this novel therapy. Methods: Sixteen globotriaosylceramide (Gb3) isoforms and eight globotriaosylsphingosine (lyso-Gb3) analogues were measured by LC-MS/MS in plasma and urine at numerous time points before and after gene therapy. Plasma and peripheral blood leukocyte α-galactosidase A activity were also measured. Results: Levels of urine and plasma lyso-Gb3 and analogues, and urine Gb3 were lower after gene therapy and while treated with enzyme replacement therapy (ERT) compared to baseline (before gene therapy) in participants treated with ERT only. Three participants chose to cease ERT treatment at some point after gene therapy. Two of these patients had lower levels of urine and plasma lyso-Gb3 and analogues compared to baseline, whereas one participant had higher levels of these biomarkers compared to baseline. An increase in urine Gb3 was observed when ERT treatment ceased after gene therapy (P < 0.05) in all three participants. Conclusion: The evaluation of this complete glycosphingolipid biomarker profile was useful in monitoring the biochemical response to gene therapy in this cohort of five patients with Fabry disease.