If at first you don't succeed, try, try again. That's Depomed's
In July, Depomed's extended-release version of Gabapentin GR failed as a treatment for post-herpetic neuralgia (PHN) -- post-shingles nerve pain. Endo Pharmaceuticals'
Shares of Depomed sank last year after it announced that Gabapentin GR failed to reach statistical significance on its primary goal -- pain reduction -- in the phase 3 PHN study. Considering that the immediate-release version of gabapentin has been around for various indications since 1994, proving its efficacy as a treatment for PHN, Depomed's failure here was somewhat surprising.
Depomed partially blamed the Gabapentin GR study failure on a higher-than-expected placebo effect in the control group (not uncommon in pain drug studies) and the size of the study's two drug-treated-patient groups. To prevent a larger-than-expected placebo effect from hampering results again, and to improve the trial's odds of success, Depomed is increasing the number of patients in this new phase 3 study, eliminating one of the drug treatment groups, and enrolling a more strictly defined patient population.
These changes will more than double the sample patient size for the Gabapentin GR once-daily treated patients (a good thing from a statistical point of view) in the study, and potentially help to reduce some of the placebo effect Depomed said it saw in the first study.
Last year was rough for Depomed, after partners King Pharmaceuticals
Fool contributor Brian Lawler does not own shares of any company mentioned in this article. Pfizer is an active pick of both the Income Investor and the Inside Value newsletters. The Fool has an A+ disclosure policy.