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Head-To-Head Study Compares Lidoderm Patch to Celebrex in Treating Osteoarthritis of the Knee
"The results of this exploratory study examining Lidoderm and Celebrex suggest that Lidoderm can alleviate the pain associated with osteoarthritis of the knee," said Alan Kivitz, M.D., of Altoona (Pa.) Center for Clinical Research. "I am encouraged by these findings since there is a critical need for new approaches to managing this type of pain."
OA affects more than 20 million Americans annually and generates more than seven million physician visits per year. If left untreated, chronic pain conditions such as OA can have significant physical, psychological and financial consequences by affecting daily functioning and quality of life.
Due to safety concerns regarding the entire COX-II inhibitor class in the fall of 2004, the sponsor of the study, Endo Pharmaceuticals Inc., voluntarily elected to prematurely halt the study prior to reaching the original enrollment target. However an analysis of data after six weeks of treatment showed that of the patients treated in the Lidoderm group (N=56), 54% experienced a 30% or greater improvement in average daily pain intensity; (studies have reported that 30% or greater reductions in pain intensity are clinically meaningful to pain patients). In the Celebrex group (N=63), 62% experienced a 30% or greater improvement in average daily pain intensity. In addition, clinically meaningful reductions in pain were noted in both treatment groups at week 12.
"Although these results need to be confirmed with further randomized controlled trials, the potential of Lidoderm to treat osteoarthritis knee pain is promising," added Dr. Kivitz. "Lidoderm has been used since 1999 to treat the pain of post-herpetic neuralgia and, because it is a non-systemic patch, has demonstrated a minimal risk of side effects or drug-to-drug interaction. Our hope is to see similar results in further Lidoderm osteoarthritis knee pain studies."
About the Study
The randomized, open-label, active-control, parallel-group study, which was intended to enroll 200 patients, contained data for 143 patients experiencing OA pain of either one or both knees and evaluated efficacy and safety of treatment. After a 7- to 14-day wash-out period during which all analgesic medications, chondroitin, and glucosamine were discontinued, patients with an average daily pain intensity score of greater-than or equal-to 5 on a scale of 0 to 10 for three of five consecutive days and an OA severity score of greater-than or equal-to 7 on a scale of 0 to 24 prior to the baseline visit were randomized to 12 weeks of treatment with either one full Lidoderm patch on the front of the knee and one-third of a patch on the back of each affected knee (69 patients) once daily for 24 hours or Celebrex 200 mg once daily (74 patients). Efficacy measures included the Western Ontario and McMaster Universities OA Index, Brief Pain Index (BPI), Pain Quality Assessment Scale and global assessments of change in OA pain and treatment satisfaction.
In the study, both treatments were well tolerated, with adverse events reported in eight patients in each group. The most common adverse events were itchiness or redness at the patch site. Additionally, three patients in the Lidoderm group discontinued the study due to adverse events. There were no discontinuations due to treatment-related adverse events in the Celebrex group.
Lidoderm (lidocaine patch 5%) is FDA-approved for the relief of pain associated with post herpetic neuralgia (PHN). Lidoderm produces an analgesic effect by the penetration of lidocaine from the patch into the epidermal and dermal layers of the skin, without loss of sensation or numbness. The Lidoderm patch should only be applied to intact skin. The most frequently reported adverse events with the Lidoderm patch are application site reactions, including erythema, edema, discoloration, burning sensation, pruritus or abnormal sensation. These reactions are generally mild and transient, resolving spontaneously within a few minutes to hours.
The FDA-approved dosing for Lidoderm is up to three patches applied for up to 12 hours within a 24-hour period. Lidoderm has not been approved by the FDA for any indications other than for the relief of pain associated with PHN, and its safety and efficacy in other indications have not been established.
Source: Endo Pharmaceuticals Inc.