Aridis Pharmaceuticals Inc. has taken a few knocks in the past year but its new agreement with the U.S. FDA is giving it an opportunity to move forward. The company’s stock (NASDAQ:ARDS) rose 115% on May 31 to close at 39 cents per share as the company and agency agreed on the design of a single confirmatory phase III superiority study of AR-301 (tosatoxumab), an adjunctive therapy for treating pneumonia caused by gram-positive bacteria Staphylococcus aureus in mechanically ventilated hospitalized patients.

Low enrollment in a phase III trial and a missed primary endpoint sent Aridis Pharmaceuticals Inc.’s shares tumbling by 35% on Jan. 26, although the company’s AR-301 (tosatoxumab) showed superior efficacy over the control group in Staphylococcus aureus ventilator-associated pneumonia (VAP) patients.