The trial met its primary efficacy endpoint, the mean change from baseline to week 12 (or last visit) of average weekly pain intensity scores, and the results were statistically significant (p<0.0001), said Neuromed. The primary efficacy endpoint was agreed upon with the FDA during the special protocol assessment process. The pivotal Phase III clinical trial of Exalgo was a double-blind, placebo-controlled study employing a randomized withdrawal design, conducted at 65 centers in the US. The study randomized 268 opioid tolerant patients with chronic moderate to severe low back pain for treatment of up to 12 weeks. Patients were considered to be opioid tolerant if they were on chronic opioid therapy at a dose equivalent to (greater than or equal to) 60mg/day of oral morphine for a period of time. The primary efficacy endpoint was the mean change from baseline to week 12 (or last visit) of average weekly pain intensity scores compared to the placebo group, measured using an 11-point Likert numerical rating scale obtained from patient diaries. The study showed statistically significant (p<0.0001) results in the protocol specified primary efficacy endpoint. In addition, results from statistical analyses of multiple secondary efficacy endpoints were consistent with the primary efficacy endpoint. The overall safety profile and reported adverse events in the study were consistent with that of other strong opioids, the company said. Neuromed is seeking approval of Exalgo in the US for the management of moderate to severe pain in opioid tolerant patients requiring continuous, around-the-clock opioid analgesia for an extended period of time. The FDA has stated in an approvable letter that one successful adequate and well-controlled clinical trial will be needed to support approval of Exalgo. Christopher Gallen, CEO of Neuromed, said: "The successful completion of our pivotal Phase III clinical trial brings us closer to reaching our goal of providing an effective once-daily pain medication for opioid tolerant patients with moderate to severe pain requiring around-the-clock opioid analgesia for an extended period of time. We have now successfully completed a major milestone of our development plan and are on schedule to submit our FDA application planned for the second quarter of 2009."