Vedolizumab Immunogenicity With Long-Term or Interrupted Treatment of Patients With Inflammatory Bowel Disease

Patients in the GEMINI 1 or 2 study (NCT00790933; Eudra CT2008-002784-14) with ulcerative colitis or Crohn disease had low immunogenicity rates after vedolizumab treatment for up to 52 weeks. We report immunogenicity rates from the GEMINI long-term safety (LTS) study using a new drug-tolerant electrochemiluminescence assay, including analyses in patients who received continuous vedolizumab induction and maintenance in GEMINI 1 or 2 and long term safety, or vedolizumab induction and placebo maintenance in GEMINI 1 or 2 followed by re-treatment in long term safety (treatment interruption). Patients were enrolled in GEMINI long term safety from GEMINI 1, 2, or 3, or as de novo vedolizumab-treated patients; all received vedolizumab 300 mg intravenously every 4 weeks. Vedolizumab antidrug antibody (ADA) status was determined by electrochemiluminescence assay; ADA-positive samples were characterized by neutralizing activity. Vedolizumab ADA data were available for 1753 patients: 1513 continuously treated with vedolizumab before/during GEMINI long term safety, 240 re-treated after treatment interruption. Among continuously treated patients, 36 (2.4%) were ADA positive (15 persistently, 20 neutralizing ADA positive). Among re-treated patients, 53 (22.1%) were ADA positive (42 persistently, 40 neutralizing ADA positive). Longitudinal immunogenicity rates increased during placebo maintenance (19.4% at week 52), then decreased in GEMINI long term safety to rates (0 at the final visit) similar to continuously treated patients. ADA positivity was 1.1% vs 2.5% (continuous treatment) and 23.1% vs 22.0% (re-treatment) among patients with and without infusion-related reactions, respectively. Long-term vedolizumab treatment was associated with generally low immunogenicity rates; vedolizumab-re-treated patients had higher rates during placebo maintenance, which decreased during re-treatment. No relationship was observed between immunogenicity and infusion-related reactions.