Shares of Ampio Pharmaceuticals Inc. jumped Wednesday after the company said its drug Ampion reduced knee pain caused by osteoarthritis in a recent study.

The company said people injected with Ampion had a 40-percent reduction in pain on average, and the drug was more effective than a saline injection. Ampio also said the patients treated with Ampion had a greater improvement in knee function compared to patients who received the saline injection.

Ampio shares climbed 90 cents, or 16.8 percent, to $6.26 in midday trading, after spiking as high as $6.99 earlier in the session.

The late-stage trial compared two doses of Ampion, and Ampio said there wasn’t a significant difference in their effectiveness. Ampio will consult with the Food and Drug Administration on the preferred dose for another late-stage study.

The Greenwood Village, Colo., company does not have any approved drugs. It is also testing a premature ejaculation and impotence drug called Zertane and an eye drug called Optina.