gms | German Medical Science

Background: C-reactive protein (CRP) is a marker of inflammation in the body and a predictor of treatment outcome in patients treated with biologic drugs. In a standard CRP test, a normal reading is less than 10 milligrams per liter (mg/L). In this study, we evaluated the difference in mean CRP levels before and after the initiation of biologic drugs and compared original and biosimilar drugs in terms of CRP reduction.

Methods: All data were drawn from the IMS® Disease Analyzer database. For this study, data were taken from 21 office-based rheumatologists who provided IQVIA with patient data, including diagnoses, prescriptions, and demographic data from 2015 until 2018. To determine the difference in mean CRP levels, patients who had received an initial biologic drug (etanercept, infliximab, adalimumab) between January 2015 and July 2018 (index date) and had documented CRP levels within six months prior to and six months after the index date were analyzed. We also performed a multivariate logistic regression analysis.

Results: This study included 1,855 patients who had received an initial biological drug therapy (1,185 with original drug and 670 with a biosimilar). After the initiation of biologic drug therapy, CRP levels significantly decreased from a mean of 27.6 mg/L before the index date to 12.4 mg/L after the index date in patients with baseline CRP ≥10 (-15.2 mg/L reduction, p-value<0.001). We observed no significant difference between patients who were started on originals and those treated with biosimilars (-15.0 versus -15.5 mg/L). Of all the patients, 61.6% treated with originals and 63.2% treated with a biosimilar drug achieved a CRP value of <10. After adjusting for age, sex, insurance status, diagnosis (rheumatoid arthritis, spondylitis), and therapy duration, we found no association between the drug (original versus biosimilar) and the likelihood of achieving a CRP value of <10 (OR:0.84; 95% CI: 0.58-1.22, p=0.357).

Conclusion: In this retrospective database study performed using 1,855 patients with rheumatoid arthritis or spondylitis, we observed no significant differences in reductions in CRP levels between original and biosimilar drugs.