Sept 4 (Reuters) - Drug developer Recro Pharma Inc said it planned to end a mid-stage trial of its lead post-operative pain drug because it did not expect the trial to achieve statistically significant results under its current design.
The company's shares fell as much as 20 percent in extended trading.
Recro said an interim analysis of the trial revealed that the drug, Dex-IN, was not effective as a standalone treatment.
The company said it planned to launch a revised trial in the fourth quarter, and expects to announce results from the fresh study in mid-2015.
Recro develops non-opioid drugs for the treatment of pain.
Opioids are a class of drugs that include morphine and methadone. They are often used as painkillers, but can cause physical dependence and addiction.
Recro said the drug reduced opioid use in a subset of patients and that no adverse events were reported during the trial. (Reporting By Amrutha Penumudi in Bangalore; Editing by Simon Jennings)