(Reuters) - AcelRX Pharmaceuticals Inc said its experimental drug device to treat post-operative pain met the main goal of controlling pain in a late-stage study among patients who had undergone knee or hip replacement surgery.
Shares of the company rose 31 percent to $8.44 in trading before the bell.
The device showed that the drug showed a decrease in pain intensity as measured on a clinical scale, compared to a placebo.
The study is the last of the three late-stage trials of the Sufentanil NanoTab PCA System, which allows patients to dose themselves with painkiller tablets.
The therapy had shown in the two earlier late-stage trials that it was at least as effective as the standard of care in treating post-operative pain and was significantly better than a placebo.