A U.S. advisory panel on Thursday narrowly backed Photocure ASA's proposed imaging drug to help detect bladder cancer.

A Food and Drug Administration advisory committee voted 9-8 that the benefits of the Hexvix product outweighed risks.

Hexvix is injected into the bladder to help illuminate cancerous lesions during a procedure called a cystoscopy. Doctors insert a thin tube with a camera into the bladder.

In a clinical trial of 814 patients, Photocure compared its product with a standard test for detecting bladder cancer.

Researchers found 16 percent of patients had tumors detected only with the Hexvix blue light method. The tumors went undetected under the standard white light diagnostic system, which was used first.

However, on the study's second main goal, Hexvix failed to demonstrate superiority over the white light system in follow-up tests performed up to nine months later, FDA reviewers said.

Supporters on the panel of outside experts said the findings were strong enough to persuade them more tumors would be caught earlier with Hexvix.

I think the study did show that you are picking up more lesions ... At the end of the day, when you have a potentially lethal cancer it's always better to know more about where it is, said Dr. Wyndham Wilson, a cancer specialist at the National Cancer Institute.

Panelists who voted against the product said they wanted more evidence that the Hexvix test led to improved health in the long term.

I wasn't convinced that detection of these lesions really changed the course of these patients' clinical outcome and that they wouldn't have been detected anyway by routine measures, said Dr. Mikkael Sekeres, a medical oncologist at the Cleveland Clinic.

Some also said the risks of repeat use were unknown.

The FDA will consider the panel's input before making the final decision on whether to approve Hexvix. The agency usually follows panel recommendations.

Yngvil Thomas, director of clinical development for Photocure, told the panel the company had provided robust results that showed Hexvix improved bladder cancer detection and reduced recurrences without increasing risks to patients.

The Norwegian drugmaker is aiming to market the product as an addition to the standard white light cystoscopy for detecting a type of bladder cancer known as non-muscle invasive papillary cancer.

Photocure Chief Executive Kjetil Hestdal said the company was pleased the majority of the panelists supported Hexvix. A final FDA decision is due by December 30, he said.

Hexvix is designed to be used with the Karl Storz Photodynamic Diagnostic system, a testing device under FDA review. Both products will need to win FDA approval for Hexvix to be sold, the FDA said.

FDA staff said no major safety concerns were found in clinical studies of Hexvix, although there were three reports of allergic reactions in countries where the drug is already approved. Agency reviewer Scheldon Kress said data could not rule out that Hexvix may have played a role but said other factors could have contributed.

Hexvix is cleared in 29 countries and has been used in more than 57,000 patients, Photocure said. GE Healthcare markets the product in Europe.

Bladder cancer primarily affects older people. Nearly 90 percent of patients are diagnosed after the age of 55.

Nearly 71,000 new cases of bladder cancer will be diagnosed in the United States in 2009, and more than 14,000 people will die from the disease, according to American Cancer Society estimates. Men are four times more likely than women to develop the cancer.