WASHINGTON, DC—The gabapentinoid anticonvulsant pregabalin (Lyrica®) may offer extended pain relief to fibromyalgia patients, according to new data presented at the 70th annual meeting of the American College of Rheumatology (ACR) in Washington, DC.1
"Pregabalin demonstrated durability of pain relief in patients who responded, and it was generally well-tolerated," said lead researcher Leslie J. Crofford, MD, the Gloria W. Singletary Professor of Rheumatology and Women's Health at the University of Kentucky in Lexington.
Pregabalin responders identified, then randomized to placebo-controlled trial
Researchers first enrolled 1051 fibromyalgia patients in an open-label 6-week study of pregabalin 300, 450 or 600 mg/day. Patients were 93% female, 88% Caucasian, and had fibromyalgia for more than 7.8 years. They rated their pain severity as a 78/100 on the visual analog scale (VAS). Each patient's pregabalin dosage was adjusted to optimize pain control and tolerability.
Response in the open-label trial was defined as >e;50% reduction in mean pain VAS score from baseline and patient self reports that they were "much improved" or "very much improved" at two of the final three visits.
A total of 663 patients completed the open-label arm, and 566 were then randomized into a 26-week double-blind, placebo-controlled study to receive either pregabalin at the optimal dosage established during the 6 weeks prior or placebo. Of these, 279 received pregabalin and 287 received placebo. The primary endpoint was time to loss of therapeutic response, defined as <30% reduction in VAS pain score from open-label baseline during two consecutive visits or subjective worsening of symptoms.
Twice as many pregabalin patients achieve long-term pain relief
There was a significant delay in time to loss of therapeutic response among those patients taking pregabalin, the study found. Specifically, 25% of patients taking placebo lost therapeutic response within 7 days, compared to 34 days among patients taking pregabalin. Overall, 61% of placebo participants lost response, compared with 32% of those taking pregabalin, indicating that pregabalin provided long-term pain relief to twice as many fibromyalgia patients as did placebo.
Pregabalin also was well-tolerated, Dr. Crofford said. Side effects included dizziness, somnolence, sinusitis, joint pain, and anxiety. There were two deaths in the study, but neither was considered treatment related.
"It's very likely that, as we learn more abut the biology of fibromyalgia, subgroups of patients who will respond better to pregabalin or to other medications will emerge," Dr. Crofford said.
Fibromyalgia algorithm needed
Eric Ruderman, MD, associate professor of medicine at the Northwestern University Feinberg School of Medicine in Chicago, told CIAOMed that pregabalin's place in the fibromyalgia treatment armamentarium is still not clear.
"It depends on a patient's symptoms," he said. "For some fibromyalgia patients. the primary symptom is pain, and in those cases, pregabalin might be used as a stand-alone treatment. There are some patients who report sleeping problems, and for them, pregabalin may be useful as an adjunct to medications that help with sleep."
"We still do not have a good treatment algorithm for fibromyalgia because symptoms are so diverse," Dr. Ruderman said. "We need medications that can be used together. There are not a lot of drug interactions with pregabalin, so it allows us to add it to other drugs that may work on another facet of fibromyalgia."
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Reference
1. Crofford LJ, Simpson S, Young JP, Jr, et al. A six-month, double-blind, placebo-controlled, durability of effect study of pregabalin for pain associated with fibromyalgia. Presented at: American College of Rheumatology Meeting; November 11–15, 2006. Washington, DC. Abstract L44.
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