Scientists at Washington University School of Medicine in St. Louis retrospectively reviewed results from off-label use of the drug valproate to treat seven adult spinal muscular atrophy (SMA) patients. Clinicians offered the drug to patients on the basis of research conducted elsewhere that showed the drug increased levels of a key protein in cell cultures.
"The treatment has been fairly successful," says lead author Chris Weihl, M.D., Ph.D., a postdoctoral fellow in neurology. "The drug appeared to be well-tolerated and increased the strength of the patients who took it."
The study, now available online, will appear in the August 8 issue of Neurology.
Weihl notes that a larger, prospective trial is needed to firmly establish valproate as a treatment of choice for sufferers of this type of SMA.
Such trials are already underway elsewhere in pediatric patients who suffer from a different type of SMA that begins earlier in life. Weihl and his colleagues are concerned that valproate may not work as well in those patients. They wanted to make sure that researchers did not discard the possibility that valproate could help older sufferers even if the trials in pediatric patients went poorly.
"Based on what we know of the unique genetics of this disease, there was reason to think that this drug could be more helpful to patients who develop SMA later in life," Weihl says.
Patients with all forms of SMA, which affects approximately one of every 6,000 babies born in the U.S., are missing the SMN1 gene, which makes the survival motor neuron (SMN) protein. This progressively weakens the muscles, leading to difficulty in walking, eating, clearing the air passageway, and other essential functions.