Regeneron Pharmaceuticals has reported that allopurinol therapy Arcalyst (rilonacept) has met has met all of the primary and secondary study endpoints of its second Phase III study, which evaluated the drug in gout patients.

The primary endpoint of the study was the number of gout flares per patient over the 16-week treatment period.

Patients who were treated with Arcalyst at a weekly, self-administered, subcutaneous dose of either 160mg or 80mg experienced a 72% decrease in the mean number of gout flares compared to the placebo group.

Arcalyst also met all the secondary endpoints of the study. Compared to the placebo, Arcalyst reduced the proportion of patients who experienced at least one gout flare during the study by 63% for Arcalyst 160mg and by 54% for Arcalyst 80mg.

Compared to placebo, Arcalyst reduced the proportion of patients who experienced two or more flares by 82% for Arcalyst 160mg and by 74% for Arcalyst 80mg.

Arcalyst was generally well-tolerated in the study, with the occurrence of serious adverse events generally well-balanced across the treatment groups.

Injection site reactions, usually considered mild, were reported more commonly with Arcalyst than with placebo.

Regeneron also announced the results from a third Phase III study, which assessed the safety of Arcalyst versus placebo over 16 weeks in 1,315 patients who were at risk for gout flares while initiating or taking uric acid-lowering drug treatment.

The study results showed that Arcalyst was generally well-tolerated, and the safety profile was consistent with that reported in the first Phase III study and second Phase III study.