Low TREM1 expression in whole blood predicts anti-TNF response in inflammatory bowel disease

Background

With the changed therapeutic armamentarium for Crohn's disease (CD) and ulcerative colitis (UC), biomarkers predicting treatment response are urgently needed. We studied whole blood and mucosal expression of genes previously reported to predict outcome to anti-TNF therapy, and investigated if the signature was specific for anti-TNF agents.

Methods

We prospectively included 54 active IBD patients (24CD, 30UC) initiating anti-TNF therapy, as well as 22 CD patients initiating ustekinumab and 51 patients initiating vedolizumab (25CD, 26UC). Whole blood expression of OSM, TREM1, TNF and TNFR2 was measured prior to start of therapy using qPCR, and mucosal gene expression in inflamed biopsies using RNA-sequencing. Response was defined as endoscopic remission (SES-CD ≤ 2 at week 24 for CD and Mayo endoscopic sub-score ≤ 1 at week 10 for UC).

Findings

Baseline whole blood TREM1 was downregulated in future anti-TNF responders, both in UC (FC = 0.53, p = .001) and CD (FC = 0.66, p = .007), as well as in the complete cohort (FC = 0.67, p < .001). Receiver operator characteristic statistics showed an area under the curve (AUC) of 0.78 (p = .001). A similar accuracy could be achieved with mucosal TREM1 (AUC 0.77, p = .003), which outperformed the accuracy of serum TREM1 (AUC 0.58, p = .31). Although differentially expressed in tissue, OSM, TNF and TNFR2 were not differentially expressed in whole blood. The TREM1 predictive signal was anti-TNF specific, as no changes were seen in ustekinumab and vedolizumab treated patients.

Interpretation

We identified low TREM-1 as a specific biomarker for anti-TNF induced endoscopic remission. These results can aid in the selection of therapy in biologic-naïve patients.

A Genetic Variation in the Neonatal Fc-Receptor Affects Anti-TNF Drug Concentrations in Inflammatory Bowel Disease

OBJECTIVES

Ample evidence exists that Anti-tumor necrosis factor (TNF) concentrations during induction determine short and long-term outcome in inflammatory bowel disease (IBD). We investigated if a variable number of tandem repeats (VNTR) polymorphism in the neonatal Fc-receptor (FcRn), responsible for extending half-life of IgG, influences anti-TNF concentrations in patients with IBD.

METHODS

Retrospective single-center study, including a cohort of 395 infliximab (IFX) naive IBD patients treated with IFX 5 mg/kg on weeks 0, 2, and 6 and a second cohort of 139 adalimumab naive patients, treated with adalimumab 160-80-40 mg on weeks 0, 2, and 4. Area under the serum anti-TNF concentration-time curve (AUC), from week 2 and 6 for IFX and week 2 and 4 for adalimumab, was used to identify factors influencing these drug concentrations.

RESULTS

The VNTR2/VNTR3 genotype was associated with a 14% lower IFX AUC compared with patients homozygous for VNTR3/VNTR3 (P=0.03), although this effect became apparent only when immunogenicity (26% lower concentrations, P=9 × 10^-5) was not present. Prior anti-TNF use predicted a 27% lower IFX AUC (P=0.002). Similarly, VNTR2/VNTR3 patients had a 24% predicted lower adalimumab AUC than VNTR3/VNTR3 patients (P=0.005). The combined presence of VNTR2/VNTR3 genotype, male gender, and prior IFX use predicted a 41% lower adalimumab AUC concentration (P=0.04).

CONCLUSIONS

The VNTR2/3 genotype in the FcRn gene is associated with lower IFX but also lower adalimumab drug exposure during induction in patients with IBD. Previously identified pharmacokinetic modifying factors were confirmed. Identifying risk factors in patients is important as higher induction doses may be needed to ensure optimal disease outcome.

Withdrawal of immunomodulators after co-treatment does not reduce trough level of infliximab in patients with Crohn's disease

BACKGROUND & AIMS

The addition of immunomodulators increases the efficacy of maintenance therapy with infliximab for up to 1 year in patients with Crohn's disease who have not been previously treated with immunomodulators. However, there are questions about the effect of withdrawing immunomodulator therapy from these patients. We studied the effects of treatment with infliximab and immunomodulators (co-treatment) and then immunomodulator withdrawal on long-term outcomes of patients, as well as trough levels of infliximab and formation of anti-infliximab antibodies (ATI).

METHODS

In a retrospective study with the median follow-up period of 34 months (interquartile range, 19-58 months), we analyzed data from 223 patients treated for Crohn's disease between May 1999 and December 2010 at the University Hospitals, Leuven, Belgium (65 received infliximab monotherapy, 158 received infliximab and an immunomodulator). Trough levels of infliximab and levels of ATI were measured in blood samples collected from 117 patients throughout co-treatment, as well as the time of immunomodulator withdrawal and after withdrawal.

RESULTS

Patients receiving co-treatment had higher trough levels of infliximab (adjusted mean increase, 1.44-fold) than those receiving infliximab monotherapy (95% confidence interval [CI], 1.07-1.92; P = .02). A smaller percentage of patients receiving co-treatment developed ATI (35 of 158, 22%) than those receiving infliximab monotherapy (25 of 65, 38%; P = .01). Among co-treated patients, levels of infliximab remained stable after immunomodulators were withdrawn (before: 3.2 μg/mL; 95% CI, 1.6-5.8 μg/mL and after: 3.7 μg/mL; 95% CI, 1.3-6.3 μg/mL; P = .70). After withdrawal of immunomodulators, 45 of 117 patients (38%) required increasing doses of infliximab, and 21 of 117 (18%) discontinued infliximab. At the time of immunomodulator withdrawal, trough levels of infliximab and C-reactive protein were most strongly associated with response to infliximab thereafter.

CONCLUSIONS

In a retrospective analysis, we confirmed that withdrawal of immunomodulators after at least 6 months (median, 13 months) of co-treatment with infliximab does not reduce the trough levels of infliximab in patients with Crohn's disease. Detectable trough levels of infliximab at the time of immunomodulator withdrawal are associated with long-term response.