NEW BRUNSWICK, N.J. — The Food and Drug Administration says Johnson and Johnson has halted a study of an additional use for its antibiotic Doribax, in patients who developed pneumonia while on a breathing machine.

The FDA says more patients taking Doribax died and fewer were cured than in the comparison group getting other drugs.

Johnson & Johnson and its Janssen Pharmaceuticals unit, which makes the injected drug, did not disclose the decision when the study was halted last May.

J&J said Friday that the study was ended on the recommendation of an independent monitoring committee. Doribax remains on the market for two approved uses, infections in the abdomen and urinary tract infections.

Johnson & Johnson shares were down 51 cents at $64.89 in midday trading.