(Reuters) - Johnson & Johnson said its drug, Tremfya, was found to be more effective than a rival medicine from Novartis AG in reducing the severity and affected area in adults with moderate-to-severe plaque psoriasis in a late-stage study.

FILE PHOTO - A Johnson & Johnson building is shown in Irvine, California, U.S., January 24, 2017. REUTERS/Mike Blake

After 48 weeks of therapy, 84.5 percent of the 1,048 participants treated with Tremfya showed 90 percent improvement in disease symptoms, as measured by the Psoriasis Area Severity Index, compared with 70 percent on Novartis’s Cosentyx, J&J said.

J&J is positioning Tremfya as a better alternative to Cosentyx as it seeks to take market share away from Novartis’s drug, which was launched two years ago and is among the top-selling treatments in the $11 billion global psoriasis market.

That market is expected to double to $21.11 billion by 2022, according to U.S. consultant Grand View Research.

With $2.1 billion in sales in 2017, Cosentyx has become one of the top revenue earners for Novartis and is expected to make up for falling revenue from its blood cancer treatment, Gleevec, whose patent expired two years ago.

On a media briefing following the release of J&J’s trial results, Novartis said it expected the data to have “limited clinical relevance” and no impact on plans to expand the Cosentyx label.

J&J also said Cosentyx demonstrated quicker effectiveness than Tremfya during the study.

“These results imply that Cosentyx remains a good option for moderate-to-severe psoriasis patients that want to achieve more rapid skin clearance,” brokerage Jefferies wrote in a note following the results.

“We see Cosentyx secure as a mainstay psoriasis therapy.”

Psoriasis is a chronic condition that causes an overproduction of skin cells, resulting in inflamed, red lesions or plaques, which can be itchy and painful.

About 7.5 million Americans live with plaque psoriasis, of which 20 percent have moderate-to-severe form of the disease, J&J said.

Tremfya, first approved in July 2017 as a plaque psoriasis treatment in the United States, is also being tested as a for psoriatic arthritis and Crohn’s disease.

Shares of J&J closed up marginally at $148. U.S.-listed shares of Novartis closed up 1.2 percent .