News on amyotrophic lateral sclerosis; Duchenne, Becker and myotonic muscular dystrophies; spinal muscular atrophy and muscle regeneration
Amytrophic lateral sclerosis (ALS)
Biogen Idec and Knopp Neurosciences announced Aug. 18, 2010, that they have entered into an agreement to continue developing KNS-760704 (dexpramipexole) as an experimental treatment for ALS. The drug helps protect nerve cells under adverse conditions. A phase 2 trial by Knopp showed the drug had favorable effects on motor function and survival in people with ALS. KNS-760704 has received Orphan Drug and Fast Track designations from the U.S. Food and Drug Administration (FDA). See Biogen Idec and Knopp Neurosciences Announce License Agreement for Late-Stage ALS Drug Candidate.
Duchenne and Becker muscular dystrophies
Acceleron Pharma announced on Aug. 19, 2010, that it has received Orphan Drug designation from the U.S. Food and Drug Administration (FDA) for its experimental Duchenne muscular dystrophy (DMD) drug ACE031. The drug, which is designed to increase muscle size and strength by blocking myostatin, a protein that inhibits muscle growth, is being tested in DMD in Canada. Orphan Drug designation provides economic incentives for companies to develop drugs for rare diseases. For more information, see:
Santhera Pharmaceuticals announced on Aug. 13, 2010, that it had received a European patent for Catena/Sovrima for the treatment of DMD and other muscular dystrophies. Catena/Sovrima is the company's patented brand of idebenone, an antioxidant. In the United States, a similar patent is pending. The drug is being tested in DMD in the United States and Europe. For more, see:
Plans are under way for a clinical trial of gene therapy involving delivery of the follistatin gene in people with Becker muscular dystrophy (BMD) and sporadic (nonfamilial) inclusion-body myositis (sIBM) at Nationwide Children's Hospital in Columbus, Ohio. The follistatin protein (made from the gene) interferes with myostatin, an inhibitor of muscle growth. MDA is not supporting this trial, but Jerry Mendell, co-director of the MDA clinic at Nationwide, is a principal investigator. The trial is not yet open for recruitment.
A new, MDA-supported study supports the concept of increasing blood flow to dystrophin-deficient muscles as a potential therapy for DMD or BMD. See Flt-1 haploinsufficiency ameliorates muscular dystrophy phenotype by developmentally increased vasculature in mdx mice. MDA also is supporting a trial of tadalafil, a vasodilating drug that may increase muscle blood flow, in men with BMD. See Tadalafil trial in Becker MD.
Myotonic muscular dsytrophy
A research team that received MDA support has shed light on how the genetic defect that underlies type 1 myotonic dystrophy (MMD1) becomes unstable, often expanding as cells divide in people with MMD1 and as it's passed from a parent with MMD1 to a child. Expansions generally correlate with worsening disease symptoms. Knowledge about the molecular mechanisms underlying the expansion process could eventually lead to better control over it. See Tissue- and age-specific DNA replication patterns at the CTG/CAG-expanded human myotonic dystrophy type 1 locus.
Spinal muscular atrophy
Three recent studies have documented various types of cardiac problems in mice genetically engineered to develop a disease resembling human spinal muscular atrophy (SMA). Although some patients with SMA have been found to have heart abnormalities, these problems have not been thought to be common in this disease. The relevance of the mouse findings to human patients isn't yet clear, but some of the researchers suggest that people with SMA should be monitored for cardiac problems. For more, see:
MDA-supported researchers report they've caused mature mouse muscle cells that have stopped dividing to revert to a stemlike, dividing state, a process called "dedifferentiation" that newts and salamanders use when regenerating lost limbs. Causing dedifferentiation in muscle cells from a mammal may bring scientists closer to improving the regenerative capacity of human muscle tissue. See Transient inactivation of Rb and ARF yields regenerative cells from postmitotic mammalian muscle.