Dystrophin expression in muscles of duchenne muscular dystrophy patients after high-density injections of normal myogenic cells.

The transplantation of myoblasts obtained from a healthy donor is a potential treatment of Duchenne muscular dystrophy (DMD). Following intramuscular injection, donor myoblasts can fuse with the myofibers of the patient and introduce the normal dystrophin gene. In a previous Phase 1A clinical trial, (Dystrophin expression in muscles of DMD patients after high-density injections of normal myogenic cells, https://www.ncbi.nlm.nih.gov/pubmed/16691118?dopt=Abstract) the investigators showed that transplantation of myoblasts grown from the muscle biopsy of a healthy donor introduced the normal dystrophin gene in the DMD myofibers, with the consequent expression of the normal dystrophin mRNA and restoration of the dystrophin protein in several myofibers.

A new Phase I/II clinical trial is now recruiting patients (Transplantation of Myoblasts to DMD Patients; https://clinicaltrials.gov/ct2/show/NCT02196467?term=duchenne&recr=Open&no_unk=Y&rank=31) to investigate whether the transplantation of normal myoblasts throughout one muscle (extensor carpi radialis) of DMD patients is safe and will improve the strength of that muscle.

In this “high-density injection” protocol, patients will be transplanted with myoblasts grown from the muscle biopsy of a healthy donor. Thirty million myoblasts will be injected per cubic cm in a progressively higher volume of muscle (i.e., 3, 6 and 9 cm cube). The contralateral muscle will be injected with saline as a negative control. The strength of both muscles will be measured at 3 months to verify if myoblast transplantation increased muscle strength. If there is no significant strength increase, the protocol will be terminated immediately for that patient. If there is a significant strength increase, the patient will be maintained under immunosuppression until 6 months and the muscle strength will be re-evaluated.