Immunogenicity
Patients were tested at multiple time points for antibodies to certolizumab pegol during Studies CD 1 and CD2. The overall percentage of antibody positive patients was 8% in patients continuously exposed to CIMZIA, approximately 6% were neutralizing in vitro. No apparent correlation of antibody development to adverse events or efficacy was observed. Patients treated with concomitant immunosuppressants had a lower rate of antibody development than patients not taking immunosuppressants at baseline (3% and 11 %, respectively). The following adverse events were reported in Crohn's disease patients who were antibody-positive (N = 100) at an incidence at least 3% higher compared to antibody-negative patients (N = 1,242): abdominal pain, arthralgia, edema peripheral, erythema nodosum, injection site eryhema, injection site pain, pain in extremity, and upper respiratory tract infection.
The overall percentage of patients with antibodies to certolizumab pegol detectable on at least occasion was 7% (l05 of 1,509) in the rheumatoid arthritis placebo-controlled trials.
Approximately one third (3%,39 of 1,509) of these patients had antibodies with neutralizing activity in vitro. Patients treated with concomitant immunosuppressants (MTX) had a lower rate of antibody development than patients not taking immunosuppressants at baseline. Patients treated with concomitant immunosuppressant therapy (MTX) in RA-I, RA-II, RA-II had a lower rate of neutralizing antibody formation overall than patients treated with CIMZIA monotherapy in RA-IV (2% vs. 8%). Both the loading dose of 400 mg every other week at Weeks 0, 2 and 4 and concomitant use ofMTX were associated with reduced immunogenicity.