Posted by not exactly on February 13, 2003, at 18:34:24
In reply to Re: Transdermal Selegiline » not exactly, posted by Jack Smith on February 13, 2003, at 16:32:39
The stated reason for the FDA rejection was insufficient efficacy data [see http://www.selegiline.com/somerset.html]. I remember that Dr. Bodkin had been very disappointed by the 'non-approval letter', since he truly believed that transdermal selegiline was a breakthrough in depression treatment. However, he was not bitter about it and never hinted of any competition conspiracies. Mostly he was frustrated by the FDA's insistence on viewing depression as a single condition, which means that a treatment that is effective for only a subset of the overall depressed population has an unfair statistical hurdle.
For the sake of argument, let's say that one-third of all depressed people are in a category (some have labelled it "atypical", "anhedonic", "anergic", or "low-dopamine" depression) which tends to respond much better to dopaminergic antidepressants than to serotonergic ones. Then imagine a medication which has a 90% (!) success rate for treating this subclass, but shows no benefit whatsoever for other types of depression. A clinical trial of this medication, when given to a random sample of depressed subjects, would therefore show an overall success rate of only 30%. But this is the kind of success rate normally seen with placebo. So the FDA concludes that the med is no better than placebo, and is therefore deemed "ineffective".
There's also the "sample bias" problem. Subjects for AD clinical trials are usually obtained by advertising for volunteers. "Typical" depressives who feel "I am miserable, I'll try anything to get well" are likely to volunteer, but "atypical" depressives who feel "why bother, what good would it do" are obviously going to be under-represented.
These are the same problems that spoiled Mirapex's chances for approval as an antidepressant (fortunately it was approved for Parkinson's treatment, so it is available).
As of last week, Dr. Bodkin either did not know, or was unwilling to divulge, a timeframe for the reapproval process. He merely stated that Somerset is now able to present the confirming data that the FDA requested, and advised me to "stay tuned" for further developments. I would guess that we'll need to wait several more months. But the good news is that the effort has not been abandoned, and appears to be going well.
BTW, there's very little official word from Somerset on this matter. The only mention of the patch on their website [http://www.somersetpharm.com/corporate/profile.html] is the brief statement: "Somerset is currently engaged in the clinical development of a selegiline transdermal system for the treatment of several indications, including Alzheimer's Disease, Depression and Parkinson's Disease."
I'll post an update if/when I learn more.
- Bob
poster:not exactly
thread:140745
URL: http://www.dr-bob.org/babble/20030208/msgs/200188.html