ZURICH (Reuters) – Patients suffering from the most severe form of childhood arthritis were less likely to experience a flare up in the disease when using Novartis’ drug Ilaris compared to a placebo, the Swiss drugmaker said on Wednesday.

Results of a final-stage study showed 62 percent of patients with systemic juvenile idiopathic arthritis (SJIA) who received Ilaris became symptom-free against 32 percent of those taking a placebo.

It also showed that one third of patients could stop taking steroids within five months of using the drug, Novartis said.

Ilaris, which is already on the market for treating cryopyrin-associated periodic syndromes, a rare inflammatory disorder, works by blocking a protein called interleukin-1 beta linked to inflammation.

Novartis said it was on track to submit the drug for regulatory approval for SJIA in both Europe and the United States, based on data from this and other late-stage phase III trials presented last year.

SJIA affects less than one child per 100,000. It causes inflammation affecting the whole body, which can involve skin rashes, fever, joint pain and swelling.

Novartis is banking on new products to help it offset patent losses on big sellers such as blood pressure treatment Diovan.

But Ilaris suffered a setback last year, when U.S. regulators said they were not ready to approve the drug to treat gout.

A separate phase II study on the use of Ilaris for the autoinflammatory disease TRAPS showed that 90 percent of patients experienced a significant improvement in symptoms after just one week of treatment with Ilaris. This rose to 95 percent after two weeks.

There are currently no approved treatments for TRAPS, a rare genetically-inherited disease, which can cause fever, skin infections, inflammation around the eyes and severe joint pain.

The studies will be presented at the European League Against Rheumatism meeting in Berlin on June 7.

(Reporting by Caroline Copley; Editing by Edwina Gibbs)