REDWOOD CITY, Calif., Aug. 23, 2012 /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 dosing of the first patient in the third of three planned Phase 3 studies for ARX-01, the Sufentanil NanoTab PCA System, its novel sublingual patient-controlled analgesia (PCA) system. This third ARX-01 Phase 3 study is a randomized, double-blind, placebo controlled efficacy and safety trial in adults following hip or knee replacement surgery. "The start of our third Phase 3 clinical trial for ARX-01 is an important milestone for our lead Sufentanil NanoTab development program," said Richard King, AcelRx's president and CEO. "The results of all three Phase 3 registration studies are expected to form the basis of a New Drug Application for ARX-01, which we plan to submit to the FDA during the third quarter of 2013. The ARX-01 System is designed to provide an attractive post-operative pain treatment alternative compared to the current standard of care that utilizes intravenous pumps primarily delivering morphine." This third study is designed to enroll approximately 400 patients, randomized 3:1 to receive 15 mcg Sufentanil NanoTabs or placebo NanoTabs. Both treatments are being delivered via the ARX-01 system at a maximum dosing rate of one NanoTab every 20 minutes to control pain. Patients will be followed for a minimum of 48 hours and, as needed, up to 72 hours after randomization. The study will be conducted at approximately 45 academic and community hospitals in the U.S. The primary endpoint is the sum of the pain intensity difference to baseline, over the 48 hour study period, or SPID-48, which is the FDA standard for post-operative acute pain studies. Secondary endpoints include pain relief scores, patient global satisfaction ratings, and use of rescue medication. The ease of set up and operation of the ARX-01 system for nursing staff and patients, respectively, will also be measured through questionnaires. Topline results for the third Phase 3 clinical study are expected to be available during the first quarter of 2013.