- AcelRx, a California-based biotech focused on developing treatments for acute pain, on Monday said its experimental opioid drug proved effective at lowering the intensity of pain among adult patients reporting to the emergency room.
- The Department of Defense has provided AcelRx with development funding for the drug, known as ARX-04, in hopes it might prove an effective analgesic on the battlefield. Unlike some other opioids, AcelRx's drug is administered under the tongue rather than by injection.
- Results from the open-label Phase 3 study showed treatment with ARX-04 led to a reduction in reported mean pain intensity, but it unclear whether the data would support approval by the Food and Drug Administration. Another Phase 3 study has completed but no results are posted yet.
AcelRx reported results from the first cohort of the most recent Phase 3 study back in February, showing ARX-04 led to a mean pain intensity decrease after one hour among 40 patients who reported to the ER with moderate-to-severe acute pain.
The second cohort, consisting of another 36 adults, was eligible to receive as many as four doses of the drug. Results showed a larger decline from baseline in mean pain intensity than in the first cohort. Seven of the 36 patients receive a second dose of ARX-04, and two received a third dose.
ARX-04 was well-tolerated and didn't lead to any drug-induced cognitive impairment—an important feature for the DOD, which hopes to use it for treating soldiers in the field.
"If borne out, ARX-04's onset of pain relief, sublingual dosage form and side effect profile could make it an attractive option for doctors considering opioid analgesic treatment in emergency rooms and field-based settings," said Pamela Palmer, chief medical officer at AcelRx.
The trial was open-label and AcelRx didn't disclose the primary endpoint for the trial (although it did say ARX-04 met its endpoint).
In addition to ARX-04, AcelRx has been developing another sublingual version of sufentanil, called Zalviso, for treatment of patients in the hospital setting. Its hopes for that drug, which is approved in Europe, hit a roadblock in the U.S. when the FDA rejected an initial application for approval in 2014.
The FDA requested a fourth Phase 3 study to evaluate Zalviso, setting back AcelRx's plans. CEO Richard King subsequently left the company several months later.