Lesson from an Alzheimer-Drug Failure: Beware Russian Clinical Trial Data

(MoneyWatch)  The unexpected Phase III failure of Dimebon (latrepirdine) -- an Alzheimer's drug being developed by Pfizer (PFE) and Medivation (MDVN) -- serves as yet another reminder that pharma execs need to be wary of Russian clinical-trial data.

Medivation decided to conduct Dimebon's first pivotal trial in Russia because the drug was already approved there as an antihistamine. And the data were impressive: a statistically significant 4-point improvement on the scale used for Alzheimer's assessment, while existing drugs deliver about 2.7 points. The FDA liked the data enough to accept the trial as one of two required for approval, and Pfizer liked them enough to fork over $225 million up front.

But the data couldn't be replicated in a global Phase III trial. As Pfizer and Medivation reported this week, even the highest Dimebon dose resulted in just a 0.1 point improvement over placebo on the Alzheimer's scale.

This is not the first time drug companies have had trouble translating good Russian clinical trial data.

It happened just last week to Novelos Therapeutics (NVLT). The biotech's lead drug, NOV-002, had shown unprecedented lung-cancer survival rates in a controlled Russian phase II trial. But the global Phase III trial failed to hit statistical significance, sending Novelos' stock plunging 80 percent.

Ditto for Antigenics (AGEN). Its cancer vaccine Oncophage (vitespen) is approved for kidney cancer in Russia, yet a global Phase III trial failed. CEO Garo Armen told Mass High Tech: "Western regulatory bureaucracies are too rigid to know how to deal with our product."

Maybe the data from the Russian Dimebon trial were on the up-and-up. Alzheimer's disease is a tough indication, after all. It has bested Neurochem, Myriad Genetics and many others.

But I'll bet investors will be taking a harder look at biotechs with Phase II data out of Russia -- and even out of other Eastern countries. Leerink Swann analyst Joshua Schimmer wrote in a report a few weeks ago that one of the biggest investor push-backs against Targacept (TRGT)'s recent positive Phase IIb trial with depression drug TC-5214 was that the study was conducted primarily in India.

He predicted at the time that good Dimebon data might boost investor confidence in TC-5214, since both had previous trials "done primarily in countries in the Eastern Hemisphere which are often considered by U.S.-centric investors as having uncertain credibility."

Russia photo by Flickr user Ed Yourdon, CC 2.0