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 (typically other pain, not being treated). There were no discontinuations due to treatment-related adverse events in the Celebrex group.
However, due to recent safety concerns regarding the entire COX-2 inhibitor class, the sponsor of the study, Endo Pharmaceuticals Inc., voluntarily elected to prematurely halt the study prior to reaching the original enrollment target of 200 patients. These results therefore need to be confirmed with further randomized controlled trials.
"This is the first clinical study that compares a prescription topical patch with a COX-2 inhibitor," said Dr. Kivitz. "The results are encouraging and establish the foundation for further studies into non-systemic options for the treatment of OA pain."
Lidoderm is topical analgesic patch, approved by the U.S. Food and Drug Administration (FDA) in 1999 to treat the pain associated with post-herpetic neuralgia (PHN), a chronic condition resulting from nerve damage caused by shingles. As it is a non-systemic treatment, Lidoderm has demonstrated a minimal risk of side effects and drug-to-drug interactions. Celebrex is a COX-2 inhibitor indicated for the treatment of arthritis pain including OA.