September 28, 2010 (Las Vegas, Nevada) — A transdermal application system containing the partial μ-opioid receptor agonist buprenorphine showed analgesic efficacy in the treatment of low back pain in opioid-naive patients, according to clinical trial results presented here at the American Academy of Pain Management 21st Annual Clinical Meeting. Buprenorphine is commonly used for the treatment of acute pain and, in the United States, for opioid dependence. A new transdermal delivery system of the drug (Butrans, Purdue Pharma LP) provides continuous delivery of this drug during a 7-day period and also effectively controls lower back pain, researchers announced. The US Food and Drug Administration recently approved the product for the management of moderate to severe chronic pain in patients requiring an around-the-clock opioid analgesic for an extended period. Purdue reports Butrans is scheduled to be marketed in January 2010. „Butrans is a class 3 opioid and the only 7-day opioid patch on the market,“ said Deborah J. Steiner, MD, medical director at Purdue Pharma LP. The transdermal drug carries a boxed warning and requires a Risk Evaluation and Mitigation Strategy as part of its approval. The double-blind, multicenter, 12-week study involved 1024 opioid-naive patients with moderate to severe chronic lower back pain. Patients received open-label transdermal buprenorphine (BTDS) during a run-in period, and 541 patients who both tolerated and responded to treatment were then randomized to receive either BTDS, 10 μg/h (BTDS 10; n = 120), or BTDS, 20 μg/h (BTDS 20; n = 137), or matching placebo patches (n = 284). The primary efficacy outcome was the „average pain over the last 24 hours“ scores at the end of the 12-week, double-blind phase. Response to treatment was evaluated according to the percentage of improvement in pain scores compared with screening values. The results showed an average improvement in pain in the last 24 hours at week 12 of −0.58 in favor of those treated with the BTDS compared with placebo (P = .0104). On the basis of a responder analysis, the proportion of patients with pain score improvement of 30% or more and 50% or more was larger in the BTDS group compared with the placebo group, Dr. Steiner noted. „We conducted responder analyses, which showed a larger percentage of patients treated with [transdermal buprenorphine] had both a greater than or equal to 30% and 50% improvement in pain from baseline,“ she said. Treatment-emergent adverse events (occurring in ≥5% patients) included nausea, application site rash, and headache. Serious adverse events occurred in 1.2% of BTDS-treated patients and 0.7% of placebo patients. There were no deaths or safety concerns arising from clinical laboratory tests. A treatment for chronic pain that requires only a once-a-week application should represent an important new option in the marketplace, said Perry G. Fine, MD, a professor of anesthesiology at the University of Utah School of Medicine in Salt Lake City. „I think it will be a very welcome addition to the formulary for chronic pain for a number of reasons, not the least of which is the fact that, in terms of a once-a-week treatment for people with some degree of disabling and opioid-responsive pain, there currently is no such thing,“ said Dr. Fine, who is president-elect of the American Academy of Pain Medicine. „The fact that [transdermal buprenorphine] is a low-dose formulation is also good thing, because there are a lot of patients who don’t need high-dose opioid therapy but who need something potent to help beyond drugs that pose other potential dangers, such as acetaminophen in higher doses. „[The patch] could be especially useful in older populations with osteoarthritis who have pain that seriously interferes with either the quality of life or sleep,“ he noted. „So I think this is really a positive event that is a long time coming.“ The study was supported by Purdue Pharma LP. Dr. Steiner is medical director at Purdue Pharma LP. Dr. Fine’s disclosures include that he is on the advisory boards for companies including Alpharma, Forest Laboratories, Ortho McNeil, Purdue Pharma, Endo, Lilly, Cephalon, and King Pharmaceuticals. American Academy of Pain Management (AAPM) 21st Annual Clinical Meeting: Poster Abstract 29. Presented September 23, 2010.
001_ButransPI (This is a File about what it is)