REDWOOD CITY, Calif., March 4, 2013 /PRNewswire/ -- AcelRx Pharmaceuticals, Inc. (Nasdaq: ACRX), a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for the treatment of acute and breakthrough pain, today announced top-line data results demonstrating that the first of two pivotal placebo-controlled Phase 3 studies for its investigational sublingual Sufentanil NanoTab PCA (patient-controlled analgesia) System met its primary endpoint. Adverse events reported in the study were generally mild or moderate in nature and similar in both placebo and treatment groups. (Logo: http://photos.prnewswire.com/prnh/20130226/MM67303LOGO) The primary endpoint evaluated pain intensity over the 48-hour study period compared to baseline, or Summed Pain Intensity Difference (SPID-48), in patients following major open abdominal surgery. Results demonstrated that patients receiving sufentanil NanoTabs realized a significantly greater SPID-48 during the study period than placebo-treated patients (p=0.001). Secondary endpoint data also showed that 24 hours and 72 hours after first dose, SPID was significantly greater in the sufentanil-treated patients than in the placebo-treated patients (p<0.001 and p=0.004 respectively). "These favorable results enable AcelRx to continue moving forward towards submission of a New Drug Application (NDA) for the Sufentanil NanoTab PCA System in the third quarter of this year," said Richard King, president and CEO of AcelRx. "In the weeks ahead, our team will work with the FDA to complete a pre-NDA meeting in support of this goal." Phase 3 Study ResultsUtilizing a randomized, double-blind, placebo-controlled design, this pivotal Phase 3 study enrolled 178 adult patients at 13 U.S. sites for the treatment of acute post-operative pain immediately following major abdominal surgery. Patients were treated for post-operative pain for a minimum of 48 hours, and up to 72 hours. Patients were randomized 2:1, with 119 patients randomized to sufentanil and 59 to placebo treatment. Both treatments were delivered by the patient, as needed, using the NanoTab System with a 20-minute lock-out period. Patients in both groups could receive up to 2 mg morphine intravenously per hour as a rescue medication, the primary purpose of this rescue medication being to provide placebo-treated patients access to pain medication to enable them to stay in the study as long as possible. Pre-rescue pain scores were imputed to minimize the impact of this rescue opioid on efficacy evaluations. Eighty, or 70.2% of the sufentanil NanoTab-treated patients completed the 48-hour study period, compared to 30 (51.7%) placebo-treated patients. Reasons for drop-out in the sufentanil- and placebo-treated groups were adverse events (5.3% and 6.9% respectively), lack of efficacy (16.7% and 31.0% respectively) and other (7.9% and 10.3% respectively). The primary endpoint measure, SPID-48, was 105.6 for sufentanil-treated patients and 55.6 for placebo-treated patients (p=0.001).