Johnson & Johnson shut down a clinical trial of antibiotic Doribax after causing excess mortality and a numerically poorer cure rate than pneumonia subjects treated with imipenem-cilastatin, the generic version of Merck’s Primaxin.

Conducted as a post-marketing requirement of the European Medicines Agency, the trial was testing Doribax on 274 patients with ventilator-associated pneumonia. Results showed that those who received the drug had a 6.7% higher rate of death (21.5%) than patients treated with an alternative (14.8%). Patients also had an 11.2% lower rate of being cured than those receiving imipenem-cilastatin.

The FDA currently is reviewing the trial results, although Shaun Mickus, a spokesman at Janssen (the Johnson & Johnson unit that markets the drug), insisted that the drug is safe and effective when used according to the label.

Doribax is approved in Europe to treat hospital-acquired pneumonia, as well as in the U.S. to treat complicated urinary tract or abdominal infections.