AcelRx Pharmaceuticals, Inc. is a pharmaceutical company focused on the development and commercialization of therapies for the treatment of moderate-to-severe acute pain. The Company operates through the segment, which includes development and commercialization of product candidates for the treatment of pain. Its lead product candidates include ARX-04, Zalviso, which utilize sublingual sufentanil, delivered through a non-invasive route of administration, and ARX-03. ARX-04 is meant for the treatment of moderate-to-severe acute pain to be administered by a healthcare professional to a patient in medically supervised settings. Zalviso is meant for the management of moderate-to-severe acute pain in hospitalized adult patients. ARX-03 provides mild sedation, anxiety reduction and pain relief for patients undergoing painful procedures in a physician's office. It also includes ARX-02, which is meant for the treatment of patients who suffer from breakthrough pain (BTP) due to cancer.