Hi scum1, haven't seen you post in a while. This is a curious question on Entyvio/vedolizumab and antibodies. I haven't seen a whole lot about
it, so did some searching this morning. It appears antibodies were encountered during the clinical trials (most of by text below is an assessment there of). Our bodies can develop an immune response to any protein put into our bodies (immunogenicity). Some were suggesting adding an immunomodulator (methodex, 6mp, imuran) along with entyvio as a precaution to antibodies (as with any other tnf-biologic) but stated it hasn't been studied for effectiveness. It's worth a try as it makes sense that it'd work the same as with the abti-tnf biologics, and bring you back into response by surpressing some of the antibodies.
6.2 Immunogenicity
As with all therapeutic proteins, there is potential for immunogenicity. In UC Trials I and II and CD Trials I and III, in patients who received ENTYVIO, the frequency of antibodies detected in patients was 13% at 24 weeks after the last dose of study drug (greater than five half-lives after last dose). During treatment, 56 of 1434 (4%) of patients treated with ENTYVIO had detectable anti-vedolizumab antibody at any time during the 52 weeks of continuous treatment. Nine of 56 patients were persistently positive (at two or more study visits) for anti-vedolizumab antibody and 33 of 56 patients developed neutralizing antibodies to vedolizumab. Among eight of these nine subjects with persistently positive anti-vedolizumab antibody and available vedolizumab concentration data, six had undetectable and two had reduced vedolizumab concentrations [see Clinical Pharmacology (12.3)]. None of the nine subjects with persistently positive anti-vedolizumab antibody achieved clinical remission at Weeks 6 or 52 in the controlled trials.
Source (Page 8 of PDF, in section 6.2):
general.takedapharm.com/content/file.aspx?FileTypeCode=ENTYVIOPI