NEW YORK – Johnson & Johnson said Thursday its experimental psoriasis drug proved more effective than top-selling treatment Enbrel in a late-stage trial, was just as safe and required far fewer injections.

It was the first trial pitting J&J's ustekinumab against Enbrel, a blockbuster treatment for the chronic skin condition. Enbrel, sold by Wyethand Amgen, commands an estimated 75 percent share of the U.S. psoriasis market.

“I would anticipate, because of its robust clinical data and ease of administration, that once released, (ustekinumab) will certainly be a first-line drug” for psoriasis, said Dr. Alan Menter, a Baylor University dermatologist who helped lead the study.

Favorable results from the three-month trial of ustekinumab, which has been awaiting U.S. and European approval since late 2007, were seen among 903 patients with moderate to severe forms of the skin condition. Results were unveiled at a medical meeting in Paris.

J&J said in August that the U.S. Food and Drug Administration had extended its review of ustekinumab by three months, to December, to study amendments to the company's marketing application. The agency did not request additional clinical trials, J&J said.

Patients in the phase 3 study received either twice-weekly injections of Enbrel, or 45-milligram or 90-milligram injections of the J&J drug at the beginning of the trial and four weeks later.

After 12 weeks, 74 percent of those receiving the higher dose of ustekinumab and 68 percent of those receiving the lower dose achieved at least a 75 percent reduction in psoriasis symptoms, such as red scaly patches. That was deemed statistically superior to the 57 percent of those in the Enbrel group who obtained such relief. The J&J drug thereby comfortably met it primary study goal.

The new drug also met a secondary goal of proving superior to Enbrel in reducing the severity of psoriasis by 90 percent or more, considered nearly complete clearance.

Such relief was seen in 36 percent of patients on low-dose ustekinumab and 45 percent on the higher dose, versus 23 percent of those receiving Enbrel.

“We've never seen clearance along the lines of what we've been seeing with ustekinumab. This is pretty dramatic,” Menter told reporters in an interview before the data were formally presented.

The incidence of side effects was comparable in all three treatment groups, he said. But patients receiving ustekinumab had far fewer cases of redness or irritation at the injection site, largely explained by the fact that the J&J drug was given only twice during the study, compared with 24 injections of Enbrel over 12 weeks.

Ustekinumab and an experimental drug being developed by Abbotients who no longer benefit from anti-TNF medicines or who cannot tolerate them, he said.

“We believe this is a significant advance, particularly with its infrequent dosing schedule,” Menter said.

In June an outside advisory panel to the FDA recommended approval of the J&J drug, saying its ability to relieve psoriasis outweighed concerns that it might increase the risk of cancer.

(Reporting by Ransdell Pierson; Editing by Steve Orlofsky and John Wallace)