NEW YORK CITY (dpa-AFX) - Pfizer Inc. (PFE) said Friday a late stage study of its neuropathic pain drug Lyrica failed to meet its primary point in patients with inadequately treated painful diabetic peripheral neuropathy, or pDPN - a form of nerve damage mainly characterized by pain in the feet. Pfizer said the drug failed to demonstrate statistical significance when compared with placebo.
The Phase 3B study dubbed A0081242 is a randomized withdrawal efficacy and safety trial of Lyrica (pregabalin) in patients with inadequately treated pDPN.
In the study, patients who had inadequate pain control while receiving a medication for pDPN were switched to Lyrica (150 or 300 mg/day) during a 6-week single-blind phase. Also, patients with 30 percent or more pain-improvement were randomized to receive placebo or to continue treatment with Lyrica for the 13-week double-blind treatment phase.
Patients who received Lyrica in the single-blind phase of the study had an improvement in mean pain score relative to baseline of 2.2 points. In patients who had 30 percent or more pain-improvement, Lyrica-treated patients had a total improvement in mean pain score of 3.9 points relative to baseline, which Pfizer said was not statistically significant when compared with placebo.
Pfizer said further analyses will be conducted on these initial results.
The most common adverse events in Lyrica-treated patients were peripheral edema, dizziness, somnolence and upper respiratory tract infection when compared with placebo.
pDPN is a form of nerve damage characterized by burning pain, pins and needles, or shooting pain in the feet and often in the hands as well. About 20 percent of people with diabetes experience pain resulting from nerve damage.
Separately, Pfizer said it has halted a late stage clinical trial of Lyrica in patients with neuropathic pain associated with HIV neuropathy, stating pain response for Lyrica was almost identical with placebo.
The study-halt follows a review of a planned interim analysis by the trial's external Data Monitoring Committee, E-DMC that raised no safety concerns.
The study dubbed A0081244 was a randomized, double-blind, placebo-controlled trial. The study protocol called for an interim efficacy analysis when about half of the planned 416 subjects had been enrolled.
The interim analysis included a total of 246 subjects randomized, and data revealed that improvements in neuropathic pain symptoms were virtually identical between Lyrica and placebo.
'The results of this study show the complexities of studying pain, particularly in a difficult-to-treat condition such as neuropathic pain associated with HIVneuropathy for which there are no approved medications in the United States,' said Steven Romano, senior vice president, Head, Medicines Development Group, Global Primary Care Business Unit, Pfizer.
Lyrica is one of Pfizer's key drugs and is currently approved in 110 countries. In the U.S., Lyrica capsules CV is approved for the management of neuropathic pain associated with diabetic peripheral neuropathy, pain after shingles, among others. In Pfizer's first quarter 2012, Lyrica had worldwide sales of $955 million, up 16 percent from last year.
PFE is trading on the NYSE at $22.40, down $0.20 or 0.91%, on a volume of 20.0 million shares. In the past year, the stock has ranged $16.63 - $23.30.
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