Polymerized-type I collagen for the treatment of patients with rheumatoid arthritis. Effect of intramuscular administration in a double blind placebo-controlled clinical trial

Objective To determine the efficacy, tolerance and safety of intramuscular injections of porcine type I collagen-PVP in patients with RA in a long term-therapy. Methods The study was a double blind placebo-controlled and included 30 patients with active RA (ACR). Patients were treated with intramuscular injections of 2 ml of collagen-PVP (3.4 mg of collagen) or 2 ml of placebo during 6 months. The follow up was done during the next 6 months. The primary endpoints included the Ritchie index (RI), swollen joint count, disease activity score (DAS), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). The secondary endpoints included morning stiffness, pain intensity on a visual analogue scale (VAS), and Spanish-health assessment questionnaire (HAQ-DI). Improvement was determined using American College of Rheumatology response criteria (ACR20, 50 and 70). Results Collagen-PVP was safe and well tolerated. There were no adverse events. Patients had a statistically significant improvement (p < 0.05) in collagen-PVP-treated vs. placebo at 6 months of treatment in: swollen joint count (7.1 +/- 0.8 vs. 16.0 +/- 1.6), RI (8.1 +/- 0.8 vs. 15.2 +/- 1.5), morning stiffness (9.2 +/- 3.1 vs. 29.1 +/- 5.9 min), HAQ-DI (50.0 +/- 10.8 vs. 22.9 +/- 10.3), DAS (3.0 +/- 0.2 vs. 4.9 +/- 0.3), ACR20 (78.6 vs. 71.4%), ACR50 (57.1 vs. 0%) and ACR70 (7.1 vs. 0%) and CRP (1.1 +/- 0.4 vs. 2.5 +/- 0.7). Patients treated with collagen-PVP required lower doses of methotrexate vs. placebo (12.6 +/- 0.6 vs. 14.2 +/- 0.7 at 6 months and 12.3 +/- 0.8 vs. 15.4 +/- 0.6 at 12 months; p < 0.05). Serological or haematological parameters remained unchanged. Conclusion Collagen-PVP has been shown to be a safe and well-tolerated drug for the long-term treatment of RA. Combination of collagen-PVP plus methotrexate was more efficacious than methotrexate alone. This biodrug can be useful in the treatment of RA.