While the role of anti-drug antibodies in mediating loss of response to infliximab (IFX) is known, it is possible that there are different clinical implications for high compared to low titers of antibodies to infliximab (ATI). The impact of ATI titer on efficacy of subsequent anti-TNF treatment has not been established previously.
This is a multicenter retrospective cohort study of individuals with IBD who discontinued infliximab due to development of ATI and were subsequently switched to adalimumab therapy. IFX anti-drug antibody titer level was measured using Mayo or Esoterix assays. We examined clinical and endoscopic response to adalimumab at 3 months, 12 months, and 2 years.
Our study included 90 patients (69 CD, 17 UC, 4 CD of the ileoanal pouch) with IBD. The median antibody titer levels for the Esoterix (208 u/mL) or Mayo clinic laboratory (236 u/mL) were similar (p > 0. 50). Patients with high ATI titers (median 824 u/ml, IQR 405-1250 u/ml) were as likely to respond to adalimumab as those with low titers (median 76u/ml, IQR 41-129 u/ml). At 3 months and 12 months, the rates of clinical response/remission to adalimumab therapy were 78% and 77%, respectively, among those with high ATI titers and 81% and 84% among those with low ATI titers (p = 0.81 and 0.62, respectively). In patients who initiated a different therapeutic mechanism after adalimumab, the response rates were similar to that observed with adalimumab.
The presence of high titers of anti-drug antibodies to IFX is not predictive of treatment failure with adalimumab.