Optimizing biologic therapies for inflammatory bowel disease (ulcerative colitis and Crohn's disease)

Therapeutic Drug Monitoring to Guide Infliximab Dose Adjustment is Associated with Better Endoscopic Outcomes than Clinical Decision Making Alone in Active Inflammatory Bowel Disease

BACKGROUND

Adequate infliximab (IFX) levels are associated with favorable outcomes in inflammatory bowel disease. Using therapeutic drug monitoring (TDM) to guide dosing is cost effective and associated with clinical improvement, but effect on endoscopic outcomes remains unclear.

METHODS

Primary responders to IFX who underwent dose escalation (2008-2014) were reviewed. Patients with active endoscopic disease were included. Two cohorts were examined: TDM-based decision to escalate (TDM) and clinical decision (non-TDM). Outcomes recorded at median 6 months after adjustment included endoscopic remission (Mayo <1, Simple Endoscopic Score for Crohn's Disease <3), C-reactive protein, and inflammatory bowel disease-specific health care utilization. Postadjustment IFX and antibodies to infliximab levels discriminant for endoscopic remission were determined. Multivariable regression evaluated independent predictors of remission.

RESULTS

Of note, 312 dose optimizations were examined (149 TDM and 163 non-TDM). Clinically, groups were similar. Sixty-three percent TDM attained postadjustment endoscopic remission compared with 48% non-TDM (P < 0.05). Sixty-nine percentage TDM had significant clinical response (57% non-TDM [P < 0.01]); fewer were hospitalized (22% TDM versus 35% non-TDM, P = 0.025). Patients with ulcerative colitis had shorter time to escalation (10 versus 20 mo, P < 0.0001). Median IFX levels increased after escalation in TDM (1.5 [pre] and 11 μg/mL [post]; P < 0.0001) and were higher than non-TDM postadjustment levels (11 versus 6.5 μg/mL, P = 0.015). Postadjustment IFX >4.5 μg/mL (area under curve = 0.8; 95% confidence interval, 0.71-0.88) and antibodies to infliximab <3.3 U/mL (area under curve = 0.70; 95% confidence interval, 0.63-0.81) were associated with endoscopic remission. Multivariable analysis showed that IFX concentration (odds ratio 1.2 [95% confidence interval, 1.1-1.3]; P < 0.0001) remained an independent predictor of endoscopic remission.

CONCLUSIONS

TDM before dose adjustment is associated with higher postadjustment levels and endoscopic remission.

The positioning of colectomy in the treatment of ulcerative colitis in the era of biologic therapy

The position of surgery in the treatment of ulcerative colitis (UC) has changed in the era of biologics. Several important questions arise in determining the optimal positioning of surgery in the treatment of UC, which has long been a challenge facing gastroenterologists and surgeons. Surgery is life-saving in some patients and leads to better bowel function and better quality of life in most patients. The benefits of surgery, however, must be weighed against the potential surgical morbidity and compromised functioning that clearly can occur. The introduction of biologic therapy has added further complexity to decisions about medical management, surgery, and the relative timing of these choices. Appropriate medical management of UC may induce and maintain remission and may prevent surgery. However, medical management also carries risks of adverse effects, and recent data suggest that delay of surgery during ineffective medical therapy can increase the chances of negative surgical outcomes. To make individualized timely treatment decisions, early collaboration between gastroenterologists and surgeons is important and more data on predictors of treatment response and positive outcomes are needed. Early identification of patients who would benefit from biologic therapy or surgery is challenging.

18F-Fluorodeoxyglucose positron-emission tomography (PET) can be used to assess inflammation non-invasively in Crohn's disease

BACKGROUND

Differential therapy requires repeated diagnostic assessment for mapping and monitoring of disease activity in Crohn's disease (CD).

PURPOSE

The purpose of this prospective study was to evaluate the accuracy of (18)F-fluorodexyglucose positron-emission tomography (FDG-PET) for non-invasive assessment of disease activity in CD.

METHODS

Forty-three patients with CD underwent ileocolonoscopy and hydromagnetic resonance imaging (hydro-MRI) as reference standards. In addition, FDG-PET was performed and correlated with clinical data, hydro-MRI, and endoscopy findings. Diagnostic accuracy was determined for all methods.

RESULTS

Two-hundred and forty-one bowel segments could be analyzed by all methods. Of 80 endoscopically inflamed segments in CD, FDG-PET detected 72 and hydro-MRI 53 segments. Overall sensitivity was 90 % (FDG-PET) versus 66 % (hydro-MRI), and specificity was 92.6 % versus 99 %. In the proximal ileum, hydro-MRI revealed inflammation in eight out of 49 patients and FDG-PET, also, detected all of these inflamed segments. Seventeen stenoses could be identified in 43 CD patients. With regard to assessment as inflammatory or fibrotic stenosis, there was good concordance between colonoscopy, hydro-MRI, and FDG-PET. In one case only, the nature of the stenosis was assessed differently. In contrast with leukocyte numbers and CDAI, there was significant correlation of FDG-PET activity with C-reactive protein and CDEIS levels (P = 0.019 and P = 0.007, respectively).

CONCLUSION

FDG-PET is able to detect mucosal inflammation in CD with high sensitivity and specificity and to enable proper assessment of inflammatory activity in stenoses. FDG-PET is, thus, a promising non-invasive technique for clinical management of CD.

Blood chemistry markers for evaluation of inflammatory activity in Crohn's disease during infliximab therapy

OBJECTIVE

There is a discrepancy between clinical activity and biomarkers in inflammatory bowel disease. The Harvey-Bradshaw index (HBi) is steadfast to evaluate disease activity. A set of biological markers (high sensitive C-reactive protein [hs-CRP], calprotectin, total nitrite, soluble urokinase Plasminogen Activator Receptor [suPAR], ghrelin and endothelin) are investigated to study inflammatory activity and correlation with HBi during infliximab therapy.

MATERIAL AND METHODS

Patients with Crohn's disease (n = 22) were assessed and blood samples drawn before and 1 week after infliximab infusion (5 mg/kg) and repeated after 6 months, and compared to healthy volunteers. Hs-CRP, calprotectin, suPAR, ghrelin and endothelin were analyzed with immunoassays, and total nitrite with Griess-reaction. Results were analyzed with Wilcoxon matched-pairs test, Mann-Whitney test and Spearman correlations.

RESULTS

After the first infusion visit, HBi and calprotectin values decreased while nitrite increased (p < 0.05). At the 6-month visit, pre-infusion index and biomarkers had returned to baseline levels. Post-infusion, again the values of HBi, hs-CRP and calprotectin decreased (p < 0.05). The suPAR levels did not change between pre- and post-infusion periods at either visit. Calprotectin, nitrite and suPAR differed from healthy controls throughout the study (p < 0.05). Endothelin decreased with each treatment but was, like ghrelin, not different from controls. We found HBi to correlate with hs-CRP (Spearman r = 0.32, p < 0.05), but calprotectin did not, neither did nitrate nor suPAR.

CONCLUSIONS

Although infliximab ameliorates Crohn's disease symptoms, inflammatory markers are not persistently normalized, indicating a chronic inflammatory condition that may require continued infliximab therapy.