(Reuters) - Teva Pharmaceutical Industries Ltd’s clinical trials of its Parkinson’s drug Azilect left U.S. drug reviewers unconvinced that the treatment slows the disease’s progression.
In documents released on Thursday, the Food and Drug Administration researchers raised concerns about the design, analysis and results of the studies.
“There is no demonstrated benefit of rasagiline (Azilect’s generic name) for slowing the rate of progression of Parkinson’s Disease,” one reviewer wrote.
However, the researchers added that “it has not been clear what sort of data would definitively establish” whether a drug modifies the disease.
There is no existing cure or treatment that slows or entirely stops the progression of Parkinson’s.
Azilect, which Teva markets alongside Danish partner Lundbeck in a number of countries, is approved to treat symptoms of the neurological disorder, such as trembling limbs, stiffness, slow movement and impaired balance.
Israel-based Teva wants to expand the drug’s indication to show that Azilect slows the clinical progression of Parkinson’s.
The FDA review was complicated by the fact that it is hard to draw a line between treating the symptoms of Parkinson’s and treating the disease.
Much is unknown about Parkinson’s, including the causes of the neurogenetic disorder. Anywhere from 500,000 to 1.5 million Americans are estimated have the disease, and nearly 60,000 are diagnosed each year, according to Parkinson’s Action Network.
Azilect received FDA approval in 2006 for use as a single drug therapy in early Parkinson’s and, in more advanced patients, in addition to levodopa, a standard treatment for the disease that can mask symptoms but does not stop the disease’s progression.
Teva’s drug works by blocking the breakdown of dopamine, a chemical that sends information to the parts of the brain that control muscle movement and coordination.
Teva was not immediately available for comment.
FDA advisers will vote October 17 on whether Teva has provided the drug regulator with enough evidence of Azilect slowing down Parkinson’s.