May 10, 2013

Three New (Unapproved) Drug Applications for Parkinson's

We haven't talked about Parkinson's for a while. Time to check in on recent news.

Three recent drug therapies show promise for people -- like me -- with Parkinson’s. The findings were presented in late March at the annual meeting of the American Academy of Neurology in San Diego, CA.

DROXIDOPA for Dizziness when Standing Up
About one fifth of the one million Americans with PD experience light-headedness when they stand up, a result of rapid blood pressure drops. Patients’ autonomic nervous systems fail to produce adequate amounts of the hormone norepinephrine when their postures change.

Dr. Robert Hauser, professor of neurology and director of the University of South Florida Parkinson's Disease and Movement Disorders Center in Tampa, studied 225 people who shared this problem. Half of those subjects received droxidopa (still unapproved in America), which the body converts into norepinephrine. The other group received a placebo.

After ten weeks, the droxidopa group had experienced a “two-fold decline” in lightheadedness and dizziness, and fell lest often.

TOZADENANT to Combat the “Wearing Off” of Levadopa
Hauser studied 420 patients who regularly experienced a decline (“wearing off”) in the effectiveness of their levadopa therapy. Subjects on average encountered about six hours of “off time” every day as a result of the wearing off effect of levadopa.

The test group received varying doses of tozadenant, in addition to their regular levadopa. After three months, subjects who received 120mg or 180mg of tozadenant recaptured about one additional hour of “on” time, during which their symptoms were adequately controlled.

Tozadenant stimulates brain receptors associated with motor function. Like droxidopa, it is not yet approved by the FDA.

AZILECT to Boost Effectiveness of Dopamine Agonists
This time, Hauser studied 321 people with early Parkinson’s who didn’t respond all that well to dopamine agonists, often the first medication PD patients receive if diagnosed when relatively young. Levodopa is the first-line medication, but in time it produces the unwelcome side effect of dyskinesia -- the reason doctors may first prescribe dopamine agonists before levodopa. Since I was already 80 when diagnosed, my neurologist went directly to levodopa for me.

Unlike levodopa, which the body converts to dopamine, dopamine agonists imitate the characteristics of dopamine.

During the 18-week test, all subjects continued taking their regular dopamine agonist meds. Half of them received an Azilect (generic rasagiline) supplement; the other half received a placebo supplement.

The Azilect -- not the placebo – group “improved by 2.4 points on a standard Parkinson's disease rating scale.”

I've described Azilect as the “gold standard” treatment for PD. It has FDA approval as a single therapy, and as an add-on to levadopa. It doesn’t have approval -- yet -- for use as an add-on to dopamine agonists. Azilect is also expensive – by far my costliest med.

The article in the e-journal Everyday Health included this (now familiar) caveat:
Each of the studies was funded by the pharmaceutical company making the particular drug: Chelsea Therapeutics paid for the blood-pressure study; Biotie Therapies Inc., supported the "wearing-off" study; and Teva Pharmaceutical Industries sponsored the Azilect study. Hauser is a consultant for all three companies.
The article also includes this comment: “Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed medical journal.”

We'll be watching.

BTW, I just learned that a friend who was diagnosed with PD over 25 years ago when he was only 40 does not take Azilect. . . and he's doing amazingly well. But PD is a very idiosyncratic: one person's experience is just that -- one person's experience.

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