Disappointment for Pfizer's Lyrica in HIV and diabetes studies

Pfizer has halted a study of its pain drug Lyrica for use in the treatment of HIV symptoms on the same day it announced that the drug had failed to reach its endpoint in a separate diabetes-related pain trial.

The US pharma firm said that it cancelled a phase III trial investigating the use of Lyrica (pregabalin) in patients with neuropathic pain associated with HIV neuropathy after an interim analysis of results indicated improvements in a patient's pain symptoms were 'virtually identical' between Lyrica and placebo. But there were no safety concerns behind the trial's withdrawal, Pfizer noted.

Lyrica is currently approved in the EU for both peripheral and general neuropathic pain (pain due to nerve damage), as well as epilepsy and generalised anxiety disorder.

“The results of this study show the complexities of studying pain, particularly in a difficult-to-treat condition such as neuropathic pain associated with HIV neuropathy for which there are no approved medications in the US,” said Dr Steven Romano, senior VP, head of medicines development group for Pfizer's global primary care business unit.

In addition, Pfizer also posted disappointing data from a phase III trial investigating Lyrica's use in patients with inadequately treated painful diabetic peripheral neuropathy (pDPN).

The study did not meet its primary endpoint of significantly improved pain control over placebo based on a pain scale of 1-10.

Pfizer said it would undertake further analyses of the results, although both sets of data appear to cut off further revenue growth for the drug, which has been one of Pfizer's biggest sellers during the past few years achieving revenues of $3.67bn for 2011.

About 20 per cent of people with diabetes develop pain from nerve damage caused by high blood-sugar levels, according to Pfizer, and about one third of people with HIV develop nerve damage as a side effect of treatment or because of the virus itself, according to the University of Chicago.