Johnson & Johnson's bid to get expanded approval for its antibiotic Doribax has been given the thumbs-up from advosirs to the US Food and Drug Administration – but only just.

The FDA’s Anti-Infective Drugs Advisory Committee voted in favour of the efficacy (7-6) and safety (8-5) data for one- and four-hour infusions of Doribax (doripenem) for the treatment of hospital-acquired and ventilator-associated pneumonia.

However the panel questioned the company's methodology for studying Doribax, including whether certain patients should have been included in trials. They voted 9 to 4 against accepting the studies submitted by J&J to support its application for expanded approval of the drug, which is already marketed for treating complicated urinary tract and abdominal infections.

In documents released ahead of the committee meeting, FDA staffers had questioned the interpretation of chest X-rays that were submitted as part of J&J's application. Also the panellists used the meeting to express their concerns about the standards adopted by the FDA to approve antibiotics.

Panel member Thomas Fleming, who was not convinced as to whether Doribax, which belongs to a class of antibacterial drugs called carbapenems, is effective enough, argued that the data showed signs that the treatment increased the risk of death. He suggested that drugmakers should show that an antibiotic lowers that risk, rather than just lowering the rates of infection.

John Rex, the panel's industry representative and a vice president at AstraZeneca, said the FDA needs to continue having discussions with the pharmaceutical industry about how trials for antibiotics, noting that “it's absolutely critical that we have a clear regulatory path".

Joanne Waldstreicher, global head of drug development at J&J, said “we recognise that there is an important need for new antibiotics to treat these serious hospital infections" and "we look forward to further discussions with the FDA as they complete their review”. The agency usually follows the recommendations of its panels.