Drug tested in LGMD2B/Miyoshi patients shows promise

Dr. Michael Sinnreich recently conducted a clinical study of a drug called bortezomib in individuals who have a particular type of mutation (called ‘missense mutations’) in the dysferlin gene.  One way missense mutations in dysferlin can lead to disease is by making the resulting protein unstable, which causes the muscle to destroy the protein before it can do its job.  Bortezomib could potentially block the destruction of the protein allowing the dysferlin to remain in the muscle cell and carry out the job it is meant to do. 

Dr. Sinnreich gave each of the three participating individuals a single dose of the drug and then tested whether their muscle cells made dysferlin protein, and if so, how much, and for how long.  No tests were done to see if the drug helped the participating individuals’ muscle disease as the drug was not given over a long enough period to have any significant therapeutic effect. 

What Dr. Sinnreich’s study showed was that Bortezomib has the ability to allow unstable dysferlin protein to remain in muscle cells for about a week after a single injection.  Dr. Sinnreich stresses that “while this clinical study shows that there is potential that bortezomib or other similar drugs could be used for the treatment of dysferlinopathy (aka LGMD2B/Miyoshi myopathy) caused by particular missense mutations, there is still a lot of work to be done to show whether this class of drugs will be safe and effective for treating dysferlinopathies.  Whether the drug is able to make a significant difference in patient’s lives, as well as which particular drug to use, at what dose, how often the drug should be given, and for how long still needs to be tested in additional clinical studies.”  Dr. Sinnreich is currently designing a larger clinical trial to test these factors.  The Jain Foundation will remain in contact with Dr. Sinnreich as he continues his work, and will certainly help to spread the word when recruitment for follow-up clinical trials begins.

Read the full text article here:

http://stm.sciencemag.org/content/6/250/250ra112.short