Avenue Therapeutics Inc. said the phase 3 trial of injectable tramadol, a pain drug, met its main goal.

Tramadol is an opioid pain medication that is taken orally. It is sold under different brand names by other manufacturers, including Ultram.

The trial was conducted in 409 patients who underwent bunionectomy surgery to remove a bunion or enlargement of the joint at the base of the big toe.

Based on the results, patients showed improvement in pain reduction over 48 hours after receiving the drug compared to placebo. The trial also met its secondary goal of improving pain score over 24 hours, with a clear demonstration of dose response.

The company will conduct a second phase 3 trial of the drug in patients who have undergone abdominoplasty surgery, or the removal of excess flesh from the abdomen, in the third quarter.

Avenue Therapeutics expects to file tramadol's new drug application with the U.S. Food and Drug Administration in late 2019.

Injectable tramadol is widely used outside the U.S. following a surgery. According to the company, patients in postoperative pain setting are often treated with schedule 2 narcotics due to a lack of options.

"[Injectable] tramadol has the potential to provide a convenient bridge to the widely prescribed oral tramadol. This combination could displace schedule 2 narcotics altogether for many patients, and provide a treatment option with less potential for abuse and a lower risk of dependence," Avenue President and CEO Lucy Lu said in a statement.

New York-based Avenue Therapeutics develops products primarily for use in the acute or intensive care hospital setting. It is owned by Fortress Biotech Inc.