The decline of anti-drug antibody titres after discontinuation of anti-TNFs: implications for predicting re-induction outcome in IBD.

Anti-drug antibodies can be elicited by infliximab and adalimumab, but the rate of their decay after therapy is stopped is unknown. To investigate the decline of anti-drug antibody titre after anti-TNF cessation, and to evaluate the clinical utility of anti-drug antibody measurement before anti-TNF re-induction. Inflammatory bowel disease (IBD) patients who stopped anti-TNF therapy and had measurable anti-drug antibodies were prospectively followed up by serial blood measurements of antibodies levels. The clinical outcome of a second cohort of patients who received re-induction by infliximab or adalimumab after a drug holiday >4 months was determined vis-à-vis their anti-drug antibodies status before re-induction. The first cohort included 22 patients with anti-drug antibodies who were prospectively followed up after cessation of anti-TNF. Sixteen had antibodies-to-infliximab (ATI) and six had antibodies-to-adalimumab (ATA). ATI titres declined within 12 months to below detection levels in 13/16 infliximab-treated patients, whereas ATA titres became undetectable in only 2/6 adalimumab-treated patients (P = 0.04). The second cohort comprised 27 patients who resumed anti-TNFs (24 infliximab, 3 adalimumab). Of these, 3/5 patients with measurable anti-drug antibodies before re-induction experienced severe hypersensitivity reaction and/or nonresponse mandating drug-discontinuation, compared to 11/22 patients who were re-induced without measurable anti-drug antibodies (OR = 1.5, 95% CI 0.2-11, P = 0.7). Antibodies to infliximab titres decline to undetectable levels within one year of cessation of infliximab in the majority of patients, whereas antibodies to adalimumab seem to persist longer after adalimumab discontinuation. Measuring antibodies to infliximab prior to infliximab re-induction is probably of little clinical utility, especially if more than a 12-month drug-holiday has elapsed.

Ben-Horin S ，Mazor Y ，Yanai H ，Ron Y ，Kopylov U ，Yavzori M ，Picard O ，Fudim E ，Maor Y ，Lahat A ，Coscas D ，Eliakim R ，Dotan I ，Chowers Y ... -  《-》

Effects of discontinuing anti-tumor necrosis factor therapy during pregnancy on the course of inflammatory bowel disease and neonatal exposure.

We assessed the course of inflammatory bowel disease (IBD) among pregnant women who stopped taking anti-tumor necrosis factor (TNF) agents. We also analyzed levels of anti-TNF agents in cord blood samples. We followed 31 pregnancies in 28 women with IBD between April 2006 and April 2011 who were treated with anti-TNF agents (18 received infliximab, and 13 received adalimumab) during pregnancy. We used enzyme-linked immunosorbent assays to measure levels of anti-TNF agents in cord blood collected from 18 newborns (12 whose mothers took infliximab, and 6 whose mothers took adalimumab). Among the patients taking infliximab, 12 (71%) discontinued treatment before gestational week 30; all patients remained in remission. All the patients taking adalimumab discontinued treatment before gestational week 30; two patients had relapses of IBD. There were 28 live births, 1 miscarriage among patients taking infliximab (at gestational week 6), and 2 miscarriages among patients taking adalimumab (at weeks 6 and 8); there were no congenital malformations. The mean cord blood level of infliximab was 6.4 ± 1.6 μg/mL; it was significantly lower among women who received the drug 10 weeks or less before delivery (2.8 ± 1.1 μg/mL) than those who received infliximab closer to delivery (10 ± 2.3 μg/mL; P = .02). Adalimumab was detected in 5 samples of cord blood (mean concentration, 1.7 ± 0.4 μg/mL); 1 cord blood sample from a woman who discontinued the treatment at gestational week 22 had an undetectable level of the drug. Discontinuation of anti-TNF therapy appears to be safe for pregnant women with quiescent IBD. However, these drugs are still detected in cord blood samples.

Zelinkova Z ，van der Ent C ，Bruin KF ，van Baalen O ，Vermeulen HG ，Smalbraak HJ ，Ouwendijk RJ ，Hoek AC ，van der Werf SD ，Kuipers EJ ，van der Woude CJ ，Dutch Delta IBD Group ... -  《-》

Levels of drug and antidrug antibodies are associated with outcome of interventions after loss of response to infliximab or adalimumab.

There is controversy about whether levels of anti-tumor necrosis factor (TNF) and antidrug antibodies (ADAs) are accurate determinants of loss of response to therapy. We analyzed the association between trough levels of anti-TNF agents or ADAs and outcomes of interventions for patients with loss of response to infliximab or adalimumab. We performed a retrospective study of pediatric and adult patients with inflammatory bowel disease and suspected loss of response to anti-TNF agents treated at medical centers throughout Israel from October 2009 through February 2013. We examined the correlation between outcomes of different interventions and trough levels of drug or ADAs during loss of response. An additional subanalysis was performed including only patients with a definite inflammatory loss of response (clinical worsening associated with increased levels of C-reactive protein or fecal calprotectin, or detection of inflammation by endoscopy, fistula discharge, or imaging studies). Among 247 patients (42 with ulcerative colitis), there were 330 loss-of-response events (188 to infliximab and 142 to adalimumab). Trough levels of adalimumab greater than 4.5 mcg/mL and infliximab greater than 3.8 mcg/mL identified patients who failed to respond to an increase in drug dosage or a switch to another anti-TNF agent with 90% specificity; these were set as adequate trough levels. Adequate trough levels identified patients who responded to expectant management or out-of-class interventions with more than 75% specificity. Levels of antibodies against adalimumab >4 microgram per mL equivalent (mcg/mL-eq) or antibodies against infliximab >9 mcg/mL-eq identified patients who did not respond to an increased drug dosage with 90% specificity. Patients with high titers of ADAs had longer durations of response when anti-TNF agents were switched than when dosage was increased (P = .03; log-rank test), although dosage increases were more effective for patients with no or low titers of ADAs (P = .02). An analysis of definite inflammatory loss-of-response events (n = 244) produced similar results; patients with adequate trough levels had a longer duration of response when they switched to a different class of agent than when anti-TNF was optimized by either a dosage increase or by a switch within the anti-TNF class (P = .002; log-rank test). The results of this retrospective analysis suggest that trough levels of drug or ADAs may guide therapeutic decisions for more than two-thirds of inflammatory bowel disease patients with either clinically suspected or definite inflammatory loss of response to therapy.

Yanai H ，Lichtenstein L ，Assa A ，Mazor Y ，Weiss B ，Levine A ，Ron Y ，Kopylov U ，Bujanover Y ，Rosenbach Y ，Ungar B ，Eliakim R ，Chowers Y ，Shamir R ，Fraser G ，Dotan I ，Ben-Horin S ... -  《-》

Antibodies against tumor necrosis factor (TNF) induce T-cell apoptosis in patients with inflammatory bowel diseases via TNF receptor 2 and intestinal CD14⁺ macrophages.

The anti-tumor necrosis factor (TNF) antibodies infliximab, adalimumab, and certolizumab pegol have proven clinical efficacy in Crohn's disease. Here, we assessed the effects of anti-TNF antibodies on apoptosis in inflammatory bowel disease (IBD). CD14(+) macrophages and CD4(+) T cells were isolated from peripheral blood and lamina propria mononuclear cells from patients with IBD and control patients. Cell surface markers and apoptosis were assessed by immunohistology and fluorescence-activated cell sorting techniques. Lamina propria CD14(+) macrophages showed significantly more frequent and higher membrane-bound TNF (mTNF) expression than CD4(+) T cells in IBD, whereas mTNF-dependent signaling proteins such as TNF receptor (TNFR) 2, TNFR-associated factor (TRAF) 2, and nuclear factor κB were induced in IBD mucosal CD4(+) T cells. Most anti-TNF antibodies did not induce T-cell apoptosis in purified peripheral or mucosal CD4(+) T cells. However, in contrast to etanercept, administration of all clinically effective anti-TNF antibodies resulted in a significant induction of T-cell apoptosis in IBD when lamina propria CD4(+) T cells expressing TNFR2(+) were cocultured with mTNF(+) CD14(+) intestinal macrophages. In contrast, no effects in control patients were noted. T-cell apoptosis in IBD occurred in vivo after treatment with adalimumab and infliximab, was critically dependent on TNFR2 signaling, and could be prevented via interleukin-6 signal transduction. Blockade of interleukin-6R signaling augmented anti-TNF-induced T-cell apoptosis in IBD. Clinically effective anti-TNF antibodies are able to induce T-cell apoptosis in IBD only when mucosal TNFR2(+) T cells are cocultured with mTNF-expressing CD14(+) macrophages. The finding that anti-TNF antibodies induce apoptosis indirectly by targeting the mTNF/TNFR2 pathway may have important implications for the development of new therapeutic strategies in IBD.

Atreya R ，Zimmer M ，Bartsch B ，Waldner MJ ，Atreya I ，Neumann H ，Hildner K ，Hoffman A ，Kiesslich R ，Rink AD ，Rau TT ，Rose-John S ，Kessler H ，Schmidt J ，Neurath MF ... -  《-》

The immunogenic part of infliximab is the F(ab')2, but measuring antibodies to the intact infliximab molecule is more clinically useful.

Ben-Horin S ，Yavzori M ，Katz L ，Kopylov U ，Picard O ，Fudim E ，Coscas D ，Bar-Meir S ，Goldstein I ，Chowers Y ... -  《-》