Regeneron's ARCALYST prevents gout attacks in Phase 3 study of patients initiating allopurinol therapy

Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) announced that a Phase 3 study in gout patients initiating allopurinol therapy to lower their uric acid levels showed that ARCALYST (rilonacept), also known as IL-1 Trap, prevented gout attacks, as measured by the primary endpoint of the number of gout flares per patient over the 16 week treatment period.

• Primary Endpoint:
  • Patients who received ARCALYST at a weekly, self-administered, subcutaneous dose of 160 milligrams (mg) had an 80% decrease in mean number of gout flares compared to the placebo group over the 16 week treatment period (0.21 flares vs. 1.06 flares, p<0.0001).
  • Patients who received ARCALYST at a weekly dose of 80 mg had a 73% decrease compared to the placebo group (0.29 flares vs. 1.06 flares, p<0.0001).  
• Key Secondary Endpoints: All secondary endpoints of the study were highly positive (p<0.001 vs. placebo).  These include:
  • Treatment with ARCALYST reduced the proportion of patients who experienced two or more flares during the study period by up to 88% (3.7% with ARCALYST 160 mg, 5.0% with ARCALYST 80 mg, and 31.6% with placebo, p<0.0001).
  • Treatment with ARCALYST reduced the proportion of patients who experienced at least one gout flare during the study period by up to 65% (16.3% with ARCALYST 160 mg, 18.8% with ARCALYST 80 mg, and 46.8% with placebo, p<0.001).

ARCALYST was generally well tolerated with no reported drug-related serious adverse events.  Injection site reaction, generally considered mild, was the most commonly reported adverse event with ARCALYST.

"Gout is a very painful and common form of arthritis that results from high levels of uric acid. Uric acid-lowering therapy, most commonly with allopurinol, is a mainstay of treatment to reduce gout flares over the long term.  Paradoxically, the initiation of uric acid-lowering therapy often triggers an increase in frequency of gout attacks in the first several months of treatment that may lead to discontinuation of therapy," stated George D. Yancopoulos, M.D., Ph.D., President of Regeneron Research Laboratories.  "This positive pivotal study showed that ARCALYST® (rilonacept) markedly reduced the occurrence of painful gout attacks in patients initiating uric acid-lowering therapy.  We look forward to data from our second efficacy study in this setting and our larger safety study.  If these additional studies are successful, we plan to file for regulatory approval by mid-2011."  

"Chronic urate-lowering therapy is critical to control the symptoms and the resulting consequences of gout in the joints.  We in the rheumatology community have long recognized the challenge of adherence to uric acid-lowering therapies.  Data suggest that many patients discontinue allopurinol within the first few months of therapy, in part due to increased flares," said H. Ralph Schumacher, M.D., Professor of Medicine, University of Pennsylvania, Philadelphia, PA.  "Current therapies recommended to reduce the risk of gout flares in patients taking uric acid-lowering therapy are under-prescribed, especially outside of rheumatology practice.  While additional Phase 3 data are needed, the results from this study suggest that concomitant use of rilonacept during the first several months of uric acid-lowering therapy may help avoid gout flares, which could, in turn, improve patient outcomes."

Results of a Phase 3 study in patients presenting with an ongoing acute gout flare showed that compared to indomethacin, a non-steroidal anti-inflammatory drug considered a standard of care, there was no significant benefit from combining indomethacin with ARCALYST, as measured by the primary endpoint of the average intensity of gout pain from 24 to 72 hours after initiation of treatment.  Patients treated with indomethacin alone experienced an average reduction in patient-reported pain scores (0 to 4 Likert scale where 0 represents no pain and 4 represents extreme pain) of 1.40 points from baseline compared to an average reduction of 1.55 points from baseline in patients treated with both indomethacin and ARCALYST.