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The PRECEPT clinical trial, with CEP-1347, was watched with great hope. Pre-clinical trials indicated it was neuroprotective. Had scientists finally come up with something that would slow or even stop the progression of Parkinson's disease? That was their hope, and mine as a trial participant.
I researched CEP-1347 extensively prior to joining the Phase II/III clinical trial. Everything indicated that it could be a winner. What did I have to lose? Okay, there was an increased risk of cancer because CEP-1347 stopped the mechanism for cell death. This was a very scary possibility, but I reasoned that I already HAD Parkinson's disease, and cancer was only a remote possibility. I decided to do what I could NOW to fight Parkinson's disease, and not let the cancer threat deter me. What I had to gain was the neuroprotection: if CEP-1347 worked as hoped, I’d have the chance to get this new treatment years before it came on the market. I had a 75% chance of getting the drug (and a 25% chance for placebo). So my chances of getting CEP-1347 were good, and oh, how I hoped I would.
In May 2005, after I’d been in the trial for nearly two years, it was abruptly halted, following scientists’ review of the 806 participants’ data after averaging 21 months on CEP-1347. Cephalon posted a notice on its website that the drug “was unlikely to provide evidence of significant effect,” [1] and the trial ended just like that.
Now, 10 months later, the trial has been unblinded. The Parkinson Study Group sent letters to their trial centers, and participants from all over the country are learning what dose they were on and the effects of CEP-1347. To everyone’s great surprise: “more participants who were assigned to CEP-1347 developed disability requiring dopaminergic treatment (dopamine agonist or levodopa) than those who were assigned to matching placebo.” [2] The results were confirmed by the two SPECT (brain) scans each participant received. In plain terms, Parkinson's disease progressed slightly faster in participants on the drug, than it did in those on a placebo. This was the complete opposite of what had been expected. Instead of being neuroprotective, CEP-1347 actually caused you to get worse faster! (Perhaps unsurprisingly, one of the people I know who did the best in the trial found out she was on the placebo.)
One researcher who wrote to me said, “the effects are minimal, but they appear to be real”…and … “they are not ‘statistically significant’ and “therefore, we do not put tremendous weight on them.” [3] But the participants see the findings differently. The majority of those with whom I am in contact are very upset that the drug caused faster disease progression, no matter.
These results illustrate that there is no guarantee about the results when you join a clinical trial. Even though I had done extensive research before joining PRECEPT, learning the drug had shown great promise – it not only failed to be neuroprotective, it appears to have caused faster progression of Parkinson's disease.
Regardless, I am philosophical about my participation in the trial. If CEP-1347 had worked as expected, I’d have been a jubilant winner, as would have been my cohorts. As it is, I admit I was glad to learn that I had been taking the lowest dose. But in the end, this experience won't keep me from joining future trial(s). I’ll do the same extensive research and take my chances.
[1] http://www.prnewswire.com/cgi-bin/stories.pl?ACCT=104&STORY=/www/story/05-11-2005/0003595559&EDATE=
[2] March 2006 Letter to Jean Burns from PSG
[3] Private correspondence to Jean Burns from a researcher
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