Effects of Transient and Persistent Anti-drug Antibodies to Certolizumab Pegol: Longitudinal Data from a 7-Year Study in Crohn's Disease.

BACKGROUND: Anti-drug antibodies (ADAbs) may decrease the efficacy of biologics and increase the risk of adverse events. A single positive test may not preclude further treatment because of variations in assays used, test timing, and patient variables. We evaluated the longitudinal patterns of immunogenicity during 7 years of antitumor necrosis factor-alpha drug certolizumab pegol (CZP) treatment for moderate-to-severe Crohn's disease. METHODS: PRECiSE 3 patients (n = 595) received open-label CZP 400 mg every 4 weeks up to 7 years. CZP-ADAb expression, plasma CZP concentration, Harvey-Bradshaw Index, C-reactive protein, and fecal calprotectin concentrations were measured multiple times. Longitudinal data, examined for CZP-ADAb positivity and categorized as transient (with temporary/no effect on CZP concentration), persistent, or negative, were correlated with clinical and biological variables. RESULTS: Of the CZP-ADAb-positive patients, 40 (22.6%) had transient CZP-ADAbs and 94 (77.4%) had persistent CZP-ADAbs. Demographic characteristics were similar between groups. Median C-reactive protein and fecal calprotectin were higher (P < 0.05 at some visits) and plasma CZP concentrations were significantly lower (P < 0.0001 at all visits) in the persistent CZP-ADAb-positive group relative to the CZP-ADAb-negative group. Transient CZP-ADAb-positive and CZP-ADAb-negative patients had similar plasma CZP, C-reactive protein, and fecal calprotectin concentrations. Median Harvey-Bradshaw Index scores and rates of adverse events were similar among groups. CONCLUSIONS: This analysis demonstrates that persistent CZP-ADAb has negative effects on drug levels and efficacy, whereas transient expression may not. Serial measurements may be needed to characterize ADAb positivity. www.clinicaltrials.gov, Number NCT00160524.