Early vedolizumab trough levels predict mucosal healing in inflammatory bowel disease: a multicentre prospective observational study.

BACKGROUND: The correlation between vedolizumab trough levels during induction therapy and mucosal healing remains unknown. AIM: To compare early vedolizumab trough levels in patients with and without mucosal healing within the first year after treatment initiation. METHODS: We prospectively collected vedolizumab trough levels in all inflammatory bowel disease patients at weeks 2, 6 and 14 of vedolizumab treatment in three French referral centres between 1 June 2014 and 31 March 2017. Results of every patient that underwent mucosal assessment by magnetic resonance imaging and/or endoscopy in the first year after treatment initiation were analysed. RESULTS: Median vedolizumab trough levels in the overall population (n = 82) were 27 µg/mL (interquartile range, IQR 21.2-33.8 µg/mL) at week 2, 23 µg/mL (IQR 15-34.5 µg/mL) at week 6 and 10.7 µg/mL (IQR 4.6-20.4 µg/mL) at week 14. Only median vedolizumab trough levels at week 6 differed between patients with and without mucosal healing within the first year after treatment initiation (26.8 vs 15.1 µg/mL, P = 0.035). A cut-off trough level of 18 µg/mL at week 6 predicted mucosal healing within the first year after the start of vedolizumab with an area under the receiver operating curve of 0.735 (95% confidence interval 0.531-0.939). A vedolizumab trough level above 18 µg/mL at week 6 was the only independent variable associated with mucosal healing within the first year of treatment (odds ratio 15.7, 95% confidence interval 2.4-173.0, P = 0.01). CONCLUSION: Early therapeutic drug monitoring might improve timely detection of vedolizumab-treated patients in need for an intensified dosing regimen.

Azathioprine dose reduction in inflammatory bowel disease patients on combination therapy: an open-label, prospective and randomised clinical trial.

BACKGROUND: Infliximab (IFX) combined with azathioprine (AZA) is more effective than IFX monotherapy in inflammatory bowel disease (IBD). AIM: To identify the AZA optimal dose that is required for efficacy when receiving combination therapy. METHODS: Patients with IBD in durable remission on combination therapy were enrolled in a 1-year, open-label, prospective trial after randomisation into three groups: AZA steady (2-2.5 mg/kg/day, n=28) vs AZA down (dose was halved 1-1.25 mg/kg/day, n=27) vs AZA stopped (n=26). Primary endpoint was failure defined as occurrence of a clinical relapse and/or any change in IBD therapy. RESULTS: Eighty-one patients were included. Five (17.9%), 3 (11.1%), and 8 (30.8%) patients experienced failure at 1 year in groups AZA steady, AZA down and AZA stopped, respectively (P=.1 across the groups). The median trough levels of IFX at inclusion were close to those measured at the end of follow-up in group AZA steady (3.65 vs 3.45 µg/mL, P=.9) and in group AZA down (3.95 vs 3.60 µg/mL, P=.5), whereas these levels dropped from 4.25 to 2.15 µg/mL (P=.02) in group AZA stopped. Four (14.3%), four (14.8%) and 11 (42.3%) patients experienced an unfavourable evolution of IFX pharmacokinetics in groups AZA steady, AZA down and AZA stopped, respectively. A threshold of 6-TGN <105 pmoles/8.108 RBC was associated with an unfavourable evolution of IFX pharmacokinetics. CONCLUSIONS: Under combination therapy, AZA dose reduction, but not withdrawal, appears to be as effective as continuation of AZA at full dose.

Addition of an immunomodulator can reverse antibody formation and loss of response in patients treated with adalimumab.

BACKGROUND: Anti-adalimumab antibodies (AAA) are associated with loss of clinical response (LOR). Addition of an immunomodulator has been shown to reverse immunogenicity and regain response with infliximab monotherapy. Similar data on adalimumab are lacking. AIM: To study the impact of immunomodulator addition on the emergence of AAA and LOR among adalimumab therapy patients. METHODS: The databases of three tertiary medical centres were reviewed to identify patients who developed AAA during adalimumab monotherapy with resultant LOR, and received an immunomodulator as a salvage combination therapy. All sera were prospectively analysed using previously described ELISA assays. Clinical response was determined using appropriate clinical scores. Elimination of AAA, designated as 'sero-reversal', elevation of drug levels and regained clinical response were the sought outcomes. RESULTS: Twenty-three patients (21 Crohn's disease, and 2 ulcerative colitis) developed AAA with subsequent LOR and were thereafter prescribed an immunomodulator as salvage therapy (thiopurine n = 14, methotrexate n = 9). Eleven patients (48%) underwent sero-reversal with gradual elimination of AAA, increase in drug trough levels and restoration of clinical response (median time to sero-reversal 5 months). In 12 patients (52%), immunogenicity and loss of response could not be reversed. There was no difference between responders and nonresponders in the type of immunomodulators used or baseline clinical characteristics. CONCLUSIONS: In almost half of inflammatory bowel disease patients developing anti-adalimumab antibodies and loss of response, established immunogenicity of adalimumab can be gradually reversed by the addition of immunomodulator therapy with restoration of a clinico-biological response. However, these observations need to be confirmed with larger studies.