Rilonacept is a fusion protein that ‘traps’ interleukin-1. This cytokine is a key player in the inflammation that occurs in gout.
Paradoxically, starting treatment to lower uric acid levels in patients with gout can trigger an attack of the disease, causing some patients to stop taking the medication.
To test the ability of rilonacept to prevent such attacks, investigators in PRE-SURGE 1 enrolled a total of 241 patients initiating allopurinol therapy.
During the 16-week study, they observed:
- 80% fewer disease flares in the patients who received 160mg rilonacept weekly than in the placebo group (0.21 vs 1.06)
- 73% fewer disease flares in the patients who received 80mg rilonacept weekly than in the placebo group (0.29 vs 1.06)
Rilonacept is administered as weekly subcutaneous injections. In PRE-SURGE 1, the most commonly reported adverse event in patients who received the drug was mild injection site reactions.
The benefit of rilonacept seems to appear only when it is used as a preventative agent. A separate study in 225 patients showed that adding rilonacept to indometacin had no extra pain-relieving effect on established gout attacks.
In Europe, rilonacept is currently approved, but not yet available, for the treatment of cryopyrin-associated periodic syndromes,. This rare hereditary condition involves excessive production of interleukin-1. Manufacturer Regeneron Pharmaceuticals plans to apply for approval in gout by mid-2011.