Novartis has been asked to give a US regulator more clinical data on its prospective gouty arthritis treatment and potential blockbuster, Ilaris, so that it can evaluate the benefit-risk profile in a subset of patients.

The Swiss drugmaker said today it would work with the US Food and Drug Administration on the next steps and that it was committed to studying ACZ885, or Ilaris, in inflammatory diseases.

Earlier this year, the FDA voted in favour of the overall efficacy, but said additional retreatment data was needed to access the overall safety profile of the drug.

Two late-stage studies showed in May that the Novartis treatment gave patients better pain relief and significantly cut the risks of new attacks compared with those taking an injectable steroid to treat gouty arthritis attacks, which can last for a week or more.

Novartis said ACZ885 was generally well tolerated in those studies, but it noted adverse events, including infections, were reported more frequently in patients treated with ACZ885 compared with those taking the injectable steroid.

The medicine is already approved to treat a rare inflammatory disorder known as Cryopyrin-Associated Periodic Syndromes (CAPS) and Novartis is also looking at its use in Systemic Juvenile Idiopathic Arthritis (SJIA).

Novartis is banking on such new products, like recently launched multiple sclerosis pill Gilenya, to help it offset patent losses on big sellers such as blood pressure treatment Diovan.

Reuters