The U.S. Food and Drug Administration yesterday rejected Teva Pharmaceutical Industries' petition to expand the label of its Parkinson's drug Azilect.
The advisory council to the FDA remained unconvinced that Azilect (rasagiline) slows the progression of Parkinson's Disease. The advisers unanimously voted to state that data from Teva's latest trial did not adequately demonstrate Azilect's ability to delay the clinical progression of Parkinson's, the incurable disease that the drug was developed to combat.
Teva had applied to expand Azilect's label based on the results of its "Adagio" clinical trials, which it published in mid-2008.
Azilect, generically known as rasagiline and already approved as a Parkinson's therapy, is the first drug to seek FDA approval as a medicine that affects the course of the neurogenetic disorder instead of merely masking its symptoms.
"This is really going to be the flagship ... and we have to be very solid in this and set a very high standard," said Dr. Robert Clancy, one of the panel members and a neurology professor at the Children's Hospital of Philadelphia.
"If we're wishy-washy with this, then the next thing that comes around is going to be expecting that being close is good enough. And this is close, but it's not good enough."
Azilect, which Teva markets alongside Danish partner Lundbeck in several countries, already has FDA approval to treat symptoms of the neurological disorder, such as trembling limbs, stiffness, slow movement and impaired balance. Teva is seeking an expansion of Azilect's label to show that the drug actually slow the clinical progression of the disease.
In Teva's latest trial, Parkinson's appeared to deteriorate more slowly in patients who started taking Azilect earlier than in those who began later. But while the 1-milligram dose appeared to slow the progression, the 2-milligram dose did not, overshadowing the results of the 1-milligram trial under review.
The life expectancy of a Parkinson's sufferer is about 20 years after diagnosis, compared with 10 years in the case of Alzheimer's, according to medical literature. Treatment for the condition exists, but doses have to be increased over time, and in some cases, the drug regimen needs to be changed.
Teva has eight patents on Azilect. The central patents expire in 2012, but the patent covering its chemical composition was extended by five years to February 2017. The drug does face generic competition: Watson Pharmaceuticals filed for U.S. marketing permission in August 2010. Drug companies in India and Canada later also filed for marketing permits in the United States.
Parkinson's affects one out of every 250 people aged 40 and up, and one in 100 from age 65. It has no cure, and Azilect was the first drug touted for its ability to slow the disease's progression. That claim, it seems, remains yet to be proven.
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