Isis Pharmaceuticals' Phase II study of ISIS-CRP demonstrated rapid, dose-dependent mean reductions of up to 67% in C-reactive protein (CRP) in rheumatoid arthritis (RA) patients with chronically elevated CRP levels.
In the placebo-controlled, multiple-dose study, 51 patients were randomised with 100mg, 200mg or 400mg dose of ISIS-CRP or placebo for a 12-week period.
The ISIS-CRP group patients showed improvements in signs and symptoms of RA, as measured by ACR20 and ACR50 scores, but the changes were statistically insignificant when compared with placebo-group patients.
In addition, patients treated with ISIS-CRP achieved substantial, dose-dependent reductions in CRP early in treatment that were prolonged through the treatment process.
The placebo group patients demonstrated a higher than expected response in both symptom score and CRP reduction.
Isis development senior vice-president Dr Richard Geary said CRP is strongly associated with the presence and severity of many diseases, including numerous inflammatory and cardiovascular diseases.
In the study, the company hoped to confirm in patients the substantial CRP-lowering activity observed in earlier clinical studies, gain additional experience with the drug before testing it in more severe indications, and to evaluate whether lowering CRP correlates with an improvement in RA symptoms, Geary said.
"We are pleased with the consistency of CRP lowering across all of our clinical studies, but we are disappointed that we did not see a greater impact on RA symptoms in these patients."
The company is currently conducting a Phase II study of ISIS-CRP in patients with atrial fibrillation and expects to report data in the first half of 2014.