Advisers to the US Food and Drug Administration have voted very firmly against recommending NiCox’ investigational pain drug naproxcinod, saying more data is required.

The FDA’s Arthritis Drugs and Drug Safety and Risk Management Advisory Committees voted 16 to one (with one abstention) that they did not have sufficient evidence to support the approval of naproxcinod for the relief of the signs and symptoms of osteoarthritis. Chair of the joint panel, Kathleen O’Neil of the University of Oklahoma, said there was “enthusiasm for the potential” of the treatment, the first in a new class of drugs known as CINODs (COX-inhibiting nitric oxide-donators), but more data was required from additional safety studies.

Most of the panelists agreed that naproxcinod, an improved version of naproxen, a non-steroidal anti-inflammatory drug that can increase blood pressure and cause stomach problems, appeared to be more effective than placebo but was not necessarily shown to be as effective as naproxen, which is available generically. FDA officials at the meeting called the company's data "unclear."

The vote was not a great surprise seeing as how documents released earlier in the week by FDA staffers who had questioned the blood pressure benefits of the French group’s drug. Following the panel’s rejection, it looks like NiCox will need to carry out long-term studies, casting doubts on the future of naproxcinod.

The Sophia Antipolis-based company is still backing the drug, claiming that naproxcinod mitigates the potential increase in blood pressure associated with other NSAIDs, However president Elizabeth Robinson said that the company was dropping from its proposed labelling any claims about gastrointestinal advantages.

The FDA is not bound by the recommendations of the advisory committees but very often follows their advice. The agency is expected to make a final decision on whether to approve naproxcinod by July 24.

It seems that investors have made their mind up, however, and at 11.30 am (UK time), NiCox shares had fallen 44% to 2.92 euros. The company is holding a conference call later today to discuss the panel’s decision in more depth.