Regeneron's ARCALYST meets primary, secondary endpoints in second Phase 3 gout flare study

Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) announced that in a second Phase 3 study (PRE-SURGE 2) in gout patients initiating allopurinol therapy, ARCALYST (rilonacept) met the primary and all secondary study endpoints. The primary endpoint was the number of gout flares per patient over the 16-week treatment period. Patients who received ARCALYST at a weekly, self-administered, subcutaneous dose of either 160 milligrams (mg) or 80 mg had a 72% decrease in mean number of gout flares compared to the placebo group (p<0.0001).  These results were consistent with those previously reported in the first, identical Phase 3 efficacy study (PRE-SURGE 1).

ARCALYST (also known as IL-1 Trap) also met all secondary endpoints of the study. Compared to placebo, treatment with ARCALYST reduced the proportion of patients who experienced at least one gout flare during the study period by 63% for ARCALYST 160mg (p<0.0001) and by 54% for ARCALYST 80 mg.

ARCALYST was generally well tolerated with the incidence of serious adverse events generally well-balanced across the placebo and ARCALYST groups.  Injection site reactions, usually considered mild, were reported more commonly with ARCALYST than with placebo.

"Gout, a serious and sometimes debilitating disease, is rapidly growing in prevalence throughout the world. Unfortunately, its management is often hampered by the occurrence of painful gout flares early during treatment with standard-of-care uric acid-lowering therapy," stated George D. Yancopoulos, M.D., Ph.D., President of Regeneron Research Laboratories. "We are pleased that this study confirmed the efficacy findings from the PRE-SURGE 1 trial demonstrating that treatment with ARCALYST reduced the incidence of such flares. With these positive Phase 3 trials in patients with gout initiating uric acid-lowering therapy, we plan to submit a supplemental Biologics License Application for U.S. regulatory approval in mid-2011."  

Regeneron also announced the results from a third Phase 3 study (RE-SURGE), which evaluated 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. In this study, ARCALYST® (rilonacept) was generally well tolerated, and the safety profile was consistent with that reported in the PRE-SURGE 1 and PRE-SURGE 2 studies.  Specifically, other than injection site reactions, the incidence of treatment-emergent adverse events was generally well-balanced among the 985 patients who received ARCALYST at a weekly, self-administered, subcutaneous dose of 160 mg and the 330 patients who received placebo.

In the RE-SURGE Phase 3 safety study, injection site reactions, usually considered mild, were reported more commonly with ARCALYST (15.2%) than with placebo (3.3%). Overall, the cumulative rate of infections was 20.1% in patients treated with ARCALYST and 19.1% in placebo patients.  Serious infections were reported in 0.5% of patients treated with ARCALYST and 0.9% of placebo patients. Deaths were reported for 0.3% of patients treated with ARCALYST and 0.9% of placebo patients.

In this safety study, efficacy was evaluated as a secondary endpoint, and all secondary endpoints were achieved. Compared to placebo, patients who received ARCALYST had a 71% decrease in mean number of patient-reported gout flares (p<0.0001). Compared to placebo, treatment with ARCALYST reduced the proportion of patients who reported at least one gout flare during the study period by 50% (p<0.0001) and reduced the proportion of patients who reported two or more flares by 66% (p<0.0001).

Detailed data from both the PRE-SURGE 2 and RE-SURGE studies will be presented at future scientific conferences.  The safety and efficacy of ARCALYST in the gout setting have not been evaluated by the U.S. Food and Drug Administration.  ARCALYST is not approved for use in gout.