AcelRx's ARX-04 meets primary and secondary endpoints in Phase 3 trial

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 that ARX-04 (sufentanil sublingual tablet, 30 mcg) met primary and secondary endpoints in a multi-center, double-blind, placebo-controlled Phase 3 trial (SAP301) designed to study the short-term treatment of patients with moderate-to-severe acute pain following ambulatory abdominal surgery. Results demonstrated that patients receiving ARX‑04, administered via a disposable, pre-filled, single-dose applicator (SDA), experienced significantly greater pain reduction compared to placebo, as measured by the time-weighted summed pain intensity difference over the first 12 hours of treatment (SPID-12) (p<0.001). Adverse events reported in the study were typical of opioid therapy and were similar for patients treated with ARX-04 and placebo, the most common of which were nausea, headache and vomiting.

"These results bring AcelRx one step closer to commercializing a sublingual sufentanil product that we believe will have a meaningful impact by providing a non-invasive treatment of moderate-to-severe acute pain in several medically supervised settings," said Dr. Pamela Palmer, founder and chief medical officer of AcelRx Pharmaceuticals. "We look forward to working with the FDA and the Department of Defense to complete the development of ARX-04 and bring this novel and much needed product to market."

The Phase 3 SAP301 trial enrolled adult patients undergoing outpatient abdominal surgery procedures at four clinical sites in the United States. Following surgery, 163 patients were randomized to receive either ARX-04 or placebo in a 2:1 active to placebo ratio. ARX-04 or placebo was administered by site staff as requested by the patient, but no more than once per hour. The intent-to-treat (ITT) population in this study averaged 40.9 years of age with an average Body Mass Index of 27.5, and had a higher percent of females to males (68%:32%). Eighty-nine percent of patients entering the study completed the 24-hour study period.

The primary endpoint of the study was the difference in the SPID-12 score of patients receiving ARX-04 compared to those receiving placebo. SPID‑12 scores were +25.8 for ARX-04-treated patients and +13.1 for placebo-treated patients; the difference between the two groups being highly statistically significant (p<0.001). Notably, the difference in pain intensity from baseline was superior for ARX-04 over placebo at the earliest time point measured (15 minutes; p=0.002). Secondary efficacy endpoints, which will be presented in detail at the upcoming American Society of Anesthesiologists Annual Meeting, were also superior for ARX-04 compared to placebo.

There were two serious adverse events (SAEs) reported during the study period, both of which were in the placebo group and resulted in early termination of the affected patients. No patient in the ARX-04 group dropped out of the study prior to 24 hours due to an adverse event. A lower percent of patients treated with ARX-04 dropped out of the study prior to 24 hours due to lack of efficacy compared to the placebo group (3.7% and 18.5%, respectively; p=0.002).

"In addition to the ambulatory surgery setting studied in this trial, we believe ARX-04 has broad application in emergency room and military settings, where patients often do not have immediate access to IV pain medications," added Howie Rosen, interim chief executive officer of AcelRx. "To that end, we expect to initiate a study this year in emergency room patients. Beyond the ER, we are researching other medically supervised settings in which ARX-04's non-invasive, rapid-acting profile would benefit patients."