Assessment of positive response is determined based on an assay cutpoint value. For the electrochemiluminescence (ECL) assay, for all summaries and listings unless specified otherwise, a positive immunogenicity response for 'Cytotoxic T-lymphocyte antigen (CTLA4) and possibly Immunoglobulin (Ig)', 'Ig and/or Junction Region', respectively, is defined as:

  1. A missing baseline immunogenicity measurement and a positive analytical laboratory reported immunogenicity response post-baseline
  2. A negative baseline immunogenicity response and a positive analytical laboratory reported immunogenicity response post-baseline
  3. A positive baseline immunogenicity response and a positive analytical laboratory reported immunogenicity response post-baseline that has a titer value strictly greater than the baseline titer value

Read more: http://www.clinicaltrials.gov/ct2/show/NCT01835470?cond=%22Arthritis%22&lup_s=08/23/2013&lup_d=30