A phase I/II clinical trial of autologous myoblast transplantation in facioscapulohumeral muscular dystrophy

International audience; Facioscapulohumeral muscular dystrophy type 1 (FSHD1) is one of the most frequent adult myopathies (1/20.000), with selective involvement of specific groups of muscles : facial, scapular fixator, anterior foreleg muscles, abdominal and humeral muscles. Vastus lateralis (VL) is usually spared clinically until late stages of the disease, and myoblasts grown from VL have similar behaviour in vivo and in vitro than myoblasts from control patients-> Proposal:Transplantation of autologous myoblast from spared muscle (VL) into an affected muscle as the Tibialis anterior (TA) muscle could locally improve the muscle’s regenerative capacities. Results and discussion: Cell productions were feasible but the quality of the initial muscle biopsy is important. Cell administrations were feasible and clinically well tolerated by all patients but one. The control of local cell distribution may be improved by echographic monitoring. Results show slight increases in twitch response and slight decrease in fatigue in the 3rd group. The combination of cell type (myoblasts) and of the modality (dense multisite injections) may have positively affected the TA muscle, BUT: No clinically significant gain of function perceived by FSHD patients, and no significant changes were noted at MRI and PET-Scan.The local FSHD1 degenerated muscle environment may be detrimental to the stability of the fibers or of the niches, and muscle regeneration may have been inefficient, too transitory, aborted or too unstable.The slight muscle strength increase may not be clinically significant for FSHD patients, but may improve the quality of life of patients with more advanced muscle loss (e.g. DMD patients) in other indications.