Improved Long-term Outcomes of Patients With Inflammatory Bowel Disease Receiving Proactive Compared With Reactive Monitoring of Serum Concentrations of Infliximab

Contemporary Management of Ulcerative Colitis

PURPOSE OF REVIEW

We discuss the newest evidence-based data on management of ulcerative colitis (UC). We emphasize risk-stratification, optimizing medical therapies, and surgical outcomes of UC.

RECENT FINDINGS

Recent medical advances include introduction of novel agents for UC. Vedolizumab, an anti-adhesion molecule, has demonstrated efficacy in moderate to severe UC. Tofacitinib, a small molecule, has also demonstrated efficacy. Data on optimization of infliximab show the superiority of combination therapy with azathioprine over monotherapy with infliximab or azathioprine alone. Data on anti-tumor necrosis factor-alpha (anti-TNF) therapeutic drug monitoring also hold promise, as do preliminary data on the dose escalation of infliximab in severe hospitalized UC. Surgical outcome data are reassuring, with new fertility data showing the effectiveness of in vitro fertilization. UC management is multi-disciplinary and changing. While novel therapies hold promise, better optimization of our current arsenal will also improve outcomes.

Subtherapeutic concentrations of infliximab and adalimumab are associated with increased disease activity in Crohn's disease

BACKGROUND

Low anti-tumor necrosis factor α (TNFα) serum concentrations may result in lack of treatment response in patients with inflammatory bowel disease. We determined the anti-TNFα drug concentrations in patients with inflammatory bowel disease and investigated whether or not subtherapeutic drug concentrations were associated with increased levels of disease activity.

METHODS

In a single-center cross-sectional study, we included patients with ulcerative colitis or Crohn's disease who were receiving infliximab or adalimumab maintenance therapy. Demographic data, disease activity symptom scores (Partial Mayo Score, Harvey Bradshaw Index), inflammatory markers [C-reactive protein (CRP), fecal calprotectin], antidrug antibodies and serum drug concentrations were recorded. Therapeutic drug concentrations were defined as 3-8 mg/liter for infliximab and 5-12 mg/liter for adalimumab.

RESULTS

Of 210 patients included, 137 (65.2%) had Crohn's disease. In the adalimumab group, subtherapeutic drug concentrations were measured in 16.7% of patients with ulcerative colitis and in 27.7% of patients with Crohn's disease. In the infliximab group, subtherapeutic drug concentrations were found in 23% (ulcerative colitis) and 30.3% (Crohn's disease) of patients. In Crohn's disease, subtherapeutic adalimumab concentrations were associated with higher fecal calprotectin and CRP concentrations compared with therapeutic concentrations. Subtherapeutic infliximab concentrations in patients with Crohn's disease were also associated with higher CRP concentrations compared with therapeutic concentrations.

CONCLUSIONS

The prevalence of subtherapeutic drug levels ranged from 17% to 30%. In patients with Crohn's disease, subtherapeutic serum drug concentrations were associated with significantly higher disease activity with both anti-TNFα agents. These findings were not observed in patients with ulcerative colitis. Clinicaltrials.gov identifier [NCT02134054].

Biological therapies in inflammatory bowel disease: Beyond anti-TNF therapies

The pharmacological management of inflammatory bowel disease (IBD) over the last two decades has transitioned from reliance on aminosalycilates, corticosteroids and immunomodulators to earlier treatment with anti-tumor necrosis factor (anti-TNF) therapy. Nevertheless, 20-30% of patients discontinue anti-TNF therapy for primary non-response and another 30-40% for losing response within one year of treatment. These undesirable therapeutic outcomes can be attributed to pharmacokinetic (anti-drug antibodies and/or low drug concentrations) or pharmacodynamic issues characterized by a non-TNF driven inflammation. The latter issues necessitate the use of medications with different mechanisms of action. Besides the biologics natalizumab, vedolizumab and ustekinumab that have already been approved for the treatment of IBD new non-anti-TNF therapies are currently under investigation including small molecule drugs against Janus kinase and sphingosine-1-phosphate receptors. This manuscript will review the medications that are in the later stages of development for the treatment of IBD and directed against immune targets other than TNF.

Long-Term Outcome of Infliximab Optimization for Overcoming Immunogenicity in Patients with Inflammatory Bowel Disease

BACKGROUND

Preliminary data suggest that treatment optimization can reverse immunogenicity and regain response in patients with IBD and secondary loss of response (SLR) to anti-TNF therapy due to antidrug antibodies. However, data regarding the long-term outcome of these patients are scarce.

AIMS

We aimed to investigate drug retention in IBD patients of whom infliximab was optimized to overcome immunogenicity and variables associated with drug retention.

METHODS

This was a retrospective, multicenter study of consecutive IBD patients with antibodies to infliximab (ATI), based on either proactive or reactive therapeutic drug monitoring, who underwent infliximab optimization (increasing dose, shortening interval, adding an immunomodulator, or combination) to overcome immunogenicity from September 2012 to July 2015; they were followed through December 2015. ATI were analyzed using the drug-tolerant Prometheus homogeneous mobility shift assay. Drug retention was defined as no need for drug discontinuation due to SLR or serious adverse event.

RESULTS

Our cohort consisted of 22 patients (Crohn's disease, n = 15). At the end of follow-up [median, (IQR): 17.3 (10.5-32.8) months] 77% (15/22) of patients were still on drug. Univariable Cox proportional hazards regression analysis identified first detectable ATI titer as the only variable associated with drug retention (HR: 0.89; 95% CI: 0.82-0.98, p = 0.016). Receiver-operating characteristic analysis identified an ATI titer < 8.8 U/mL associated with drug retention.

CONCLUSIONS

In real-life clinical practice, optimization of infliximab therapy can prevent drug discontinuation in approximately 3/4 of patients with ATI, especially in those with low titers. Large prospective studies are needed to confirm these data.

Infliximab trough concentrations during maintenance therapy are associated with endoscopic and histologic healing in ulcerative colitis

BACKGROUND

Endoscopic and histologic healing are emerging as new therapeutic goals in ulcerative colitis (UC), as these endpoints are associated with less relapse, hospitalization and colectomy.

AIM

To investigate the association of serum infliximab trough concentrations during maintenance therapy with endoscopic or histologic healing in UC.

METHODS

In this multi-center retrospective cohort study, we included consecutive patients with moderate-to-severe UC on infliximab maintenance therapy who had an endoscopic evaluation and underwent therapeutic drug monitoring within three months of the colonoscopy, between February 2008 and March 2016. Per event analysis was performed. Endoscopic healing was defined as Mayo endoscopic sub-score of ≤1. Histologic healing was defined as no or only focal mild active inflammation.

RESULTS

Seventy colonoscopies from 56 patients were evaluated. Infliximab trough concentrations (median [interquartile range]) were significantly higher in patients with endoscopic (11.3 [7.6-14.5] vs 6.3 [0-9.8] μg/mL, P < .001) or histologic (11.1 [6.7-14.5] vs 6.7 [0-9.9] μg/mL, P = .002) healing, respectively, compared to patients without healing. Receiver-operating characteristic analyses identified infliximab trough concentration thresholds of 7.5 (area under the curve [AUC]: 0.758) and 10.5 (AUC: 0.721) μg/mL to be associated with endoscopic and histologic healing, respectively. Multiple logistic regression analysis identified infliximab trough concentration ≥7.5 (P = .013; odds ratio [OR]: 4.3; 95% confidence intervals [CI]: 1.4-13.3) and ≥10.5 μg/mL (P = .013; OR: 3.8; 95% CI: 1.3-11) as independent factors associated with endoscopic and histologic healing, respectively.

CONCLUSIONS

This study demonstrated that infliximab trough concentrations during maintenance therapy are associated with endoscopic and histologic healing in patients with UC.

Inflammatory bowel disease: towards a personalized medicine

The management of inflammatory bowel disease (IBD) has been transformed over the last two decades by the arrival of tumor necrosis factor (TNF) antagonist agents. Recently, alternative drugs have been approved, directed at leukocyte-trafficking molecules (vedolizumab) or other inflammatory cytokines (ustekinumab). New therapeutics are currently being developed in IBD and represent promising targets as they involve other mechanisms of action (JAK molecules, Smad 7 antisense oligonucleotide etc.). Beyond TNF antagonist agents, these alternative drugs are needed for early-stage treatment of patients with aggressive IBD or when the disease is resistant to conventional therapy. Personalized medicine involves the determination of patients with a high risk of progression and complications, and better characterization of patients who may respond preferentially to specific therapies. Indeed, more and more studies aim to identify factors predictive of drug response (corresponding to a specific signaling pathway) that could better manage treatment for patients with IBD. Once treatment has started, disease monitoring is essential and remote patient care could in some circumstances be an attractive option. Telemedicine improves medical adherence and quality of life, and has a positive impact on health outcomes of patients with IBD. This review discusses the current application of personalized medicine to the management of patients with IBD and the advantages and limits of telemedicine in IBD.

Changing treatment paradigms for the management of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and progressive inf lammatory condition of the gastrointestinal tract causing bowel damage, hospitalizations, surgeries, and disability. Although there has been much progress in the management of IBD with established and evolving therapies, most current approaches have failed to change the natural course. Therefore, the treatment approach and follow-up of patients with IBD have undergone a significant change. Usage of immunosuppressants and/or biologics early during the course of the disease, known as top-down or accelerated step-up approach, was shown to be superior to conventional management in patients who had been recently diagnosed with IBD. This approach can be applied to selected groups based on prognostic factors to control disease activity and prevent progressive disease. Therapeutic targets have been shifted from clinical remission mainly based on symptoms to objective parameters such as endoscopic healing due to the discrepancies observed between symptoms, objectively evaluated inf lammatory activity, and intestinal damage. The concept of treat-to-target in IBD has been supported by population-based cohort studies, post hoc analysis of clinical trials, and meta-analysis, but more evidence is needed to support this concept to be applied to the clinical practice. In addition, individualized approach with tight monitoring of non-invasive biomarker such as C-reactive protein and fecal calprotectin and drug concentration has shown to improve clinical and endoscopic outcomes. An appropriate de-escalation strategy is considered based on patient demographics, disease features, current disease status, and patients' preferences.

A retrospective examination of the US Food and Drug Administration's clinical pharmacology reviews of oncology biologics for potential use of therapeutic drug monitoring

Background

Biologics have gained traction for use in oncology, but have demonstrate clinical variability for efficacy and safety. Therapeutic drug monitoring (TDM) can benefit patients’ outcomes from a biologic therapy when the latter has a defined therapeutic window. A clinically relevant therapeutic window may exist for biologics with established exposure-response (E–R) relationships for efficacy and/or safety and a documented maximum tolerated dose (MTD). Additionally, the inter-individual variability (IIV) on the clearance (CL) parameter could determine risks for patients falling outside the proposed therapeutic window.

Materials and methods

The US Food and Drug Administration (FDA)-approved oncology biologics between 2005–2016 were reviewed via FDA “Purple Book” (FDA-repository for licensed biologics). Data were extracted from biologics’ pharmacokinetic models available on the clinical pharmacology reviews published on the FDA-Approved Drug Products website. Evaluated features for biologics with established E–R relationships for efficacy and/or safety and MTD include an IIV for the CL and various other covariates including demographic factors, disease factors, blood chemistry, or immunogenicity.

Results

Five therapies were identified with documented E–R relationships for both efficacy and safety including, Yervoy^®(ipilimumab), Zaltrap^® (ziv-aflibercept), Portrazza^® (necitumumab), Adcetris^® (brentuximab-vedotin), and Blincyto^® (blinatumomab). The corresponding IIV on CL were: 34%, 33%, 29%, 47%, and 97%, respectively. Among the five therapies, only three had defined MTD including, brentuximab-vedotin, necitumumab, and blinatumomab.

Conclusion

Of the medications examined, blinatumomab was identified as the anticancer drug with the most available information for the establishment of TDM, and hence, may benefit through the use of TDM to optimize effectiveness and minimize patients’ toxicity. The approach used here may provide a generalizable framework to retrospectively identify anticancer biologics with high IIV that may benefit from TDM to improve patients’ clinical outcome.

A Survey Study of Gastroenterologists' Attitudes and Barriers Toward Therapeutic Drug Monitoring of Anti-TNF Therapy in Inflammatory Bowel Disease

BACKGROUND

Therapeutic drug monitoring (TDM) may improve the efficacy and cost-effectiveness of anti-TNF therapy. A standardized approach of utilizing TDM has not been established. The objective of this study was to determine gastroenterologists' attitudes and barriers toward TDM of anti-TNF therapy in clinical practice.

METHODS

An 18-question survey was distributed to members of the American College of Gastroenterology and Crohn's and Colitis Foundation via email. We collected physician characteristics, practice demographics, and data regarding TDM use and perceived barriers to TDM. Factors associated with the use of TDM were determined by logistic regression analysis.

RESULTS

A total of 403 gastroenterologists from 42 US states (76.4% male) met inclusion criteria: 90.1% use TDM, mostly reactively for secondary loss of response (87.1%) and primary nonresponse (66%); 36.6% use TDM proactively. The greatest barriers to TDM implementation were uncertainty about insurance coverage (77.9%), high out-of-pocket patient costs (76.4%), and time lag from serum sample to result (38.5%). Factors independently associated with the use of TDM and proactive TDM were practice in an academic setting (P = 0.019), and more IBD patients seen per month (P = 0.015), and Crohn's and Colitis Foundation membership (P < 0.001), and more IBD patients on anti-TNF therapy per month (P = 0.006), respectively. If all barriers were removed, an additional one-third of physicians would apply proactive TDM.

CONCLUSIONS

Lack of insurance coverage, high out-of-pocket costs, and the time lag from test to result limit use of TDM in the United States. Validation of low-cost assays, point of care testing, and studies that standardize the use of TDM are needed to make TDM more commonplace.

Associations between inflammatory bowel diseases and vitamin D

Inflammatory Bowel Diseases (IBD) are increasing sharply, and the common medications are not effective for most patients. Vitamin D (VD) has been considerate to reduce inflammatory processes and may be helpful in IBD. The aim of this review was to perform an update on the potential role of VD in the IBD. We performed a search for articles associating VD and IBD published in MEDLINE-PubMed and EMBASE. The focused question used for the search was "What is the association between Inflammatory Bowel Disease and Vitamin D?" The exclusion criteria for this search were studies not in English, editorials, case reports, or poster presentations. VD prevents the inflammatory process such as negatively interfering with the release of Interleukin (IL)-1, IL-6, and Tumour Necrosis Factor-α; enhancing the function of the intestinal epithelial barrier; decreasing the occurrence of apoptosis; stimulating Toll-Like Receptor-4; inducing the production of an antimicrobial peptide in Paneth cells. Furthermore, deficiency of VD is related to the severity of the symptoms and increased the risk of cancer and surgery. In conclusion, VD shows a potential role in the management of IBD, the supplementation is inexpensive, safe, and leads to improvement of the quality of life.

Review article: consensus statements on therapeutic drug monitoring of anti-tumour necrosis factor therapy in inflammatory bowel diseases

BACKGROUND

Therapeutic drug monitoring (TDM) in inflammatory bowel disease (IBD) patients receiving anti-tumour necrosis factor (TNF) agents can help optimise outcomes. Consensus statements based on current evidence will help the development of treatment guidelines.

AIM

To develop evidence-based consensus statements for TDM-guided anti-TNF therapy in IBD.

METHODS

A committee of 25 Australian and international experts was assembled. The initial draft statements were produced following a systematic literature search. A modified Delphi technique was used with 3 iterations. Statements were modified according to anonymous voting and feedback at each iteration. Statements with 80% agreement without or with minor reservation were accepted.

RESULTS

22/24 statements met criteria for consensus. For anti-TNF agents, TDM should be performed upon treatment failure, following successful induction, when contemplating a drug holiday and periodically in clinical remission only when results would change management. To achieve clinical remission in luminal IBD, infliximab and adalimumab trough concentrations in the range of 3-8 and 5-12 μg/mL, respectively, were deemed appropriate. The range may differ for different disease phenotypes or treatment endpoints-such as fistulising disease or to achieve mucosal healing. In treatment failure, TDM may identify mechanisms to guide subsequent decision-making. In stable clinical response, TDM-guided dosing may avoid future relapse. Data indicate drug-tolerant anti-drug antibody assays do not offer an advantage over drug-sensitive assays. Further data are required prior to recommending TDM for non-anti-TNF biological agents.

CONCLUSION

Consensus statements support the role of TDM in optimising anti-TNF agents to treat IBD, especially in situations of treatment failure.

Therapeutic Drug Monitoring in Inflammatory Bowel Disease: History and Future Directions

Clinical trials for the most effective drugs in the armamentarium of medications for inflammatory bowel disease (IBD) have shown only a 50-60% response rate, and this drops to 30% in maintenance. However, therapeutic drug monitoring (TDM) to adjust dosing to account for patient-specific characteristics, which has been shown to improve outcomes, was not utilized in these trials. This review will detail the development of TDM within the IBD space as it evolved from thiopurines to biologics and continues to evolve with loftier treat-to-target goals and more sophisticated dashboard systems.

Out-of-Pocket Cost Is a Barrier to Therapeutic Drug Monitoring in Inflammatory Bowel Disease

BACKGROUND

Therapeutic drug monitoring (TDM) is increasingly performed to optimize biologic therapy in inflammatory bowel disease (IBD). However, patients and physicians may be reluctant to perform TDM due to concerns related to potential out-of-pocket costs.

AIMS

The aim of this study was to evaluate patient understanding and attitudes toward TDM in different clinical scenarios with and without potential out-of-pocket costs.

METHODS

Adult IBD patients at a tertiary gastroenterology clinic were anonymously surveyed from March to September 2016 to assess their understanding of and willingness to undergo TDM in a variety of clinical scenarios, both with and without a potential out-of-pocket cost. Responses were analyzed for associations with changes in attitudes if out-of-pocket costs were involved.

RESULTS

Of 118 completed surveys, 68.2% of patients were aware of or had previously undergone TDM. Patient willingness to undergo TDM was high both with and without potential out-of-pocket costs (70 and 98%, respectively); however, patients were significantly less willing with out-of-pocket cost (p < 0.01). Higher disease-related quality of life scores, as measured by the short inflammatory bowel disease questionnaire (SIBDQ), was significantly associated with an increased willingness to assume a potential out-of-pocket cost (p = 0.007).

CONCLUSIONS

Overall, patients understand and are willing to undergo TDM in certain potentially beneficial clinical scenarios, however, are significantly less willing if paying out-of-pocket. A higher SIBDQ score was associated with an increase in willingness to undergo TDM when out-of-pocket cost was involved. Physicians should discuss TDM with their patients in order to make an informed and personalized treatment decision.

Defining and predicting deep remission in patients with perianal fistulizing Crohn’s disease on anti-tumor necrosis factor therapy

Perianal fistulas can occur to up to one-third of patients with Crohn’s disease (CD) leading to significant disabling disease and morbidity. Fistulising perianal CD treatment often necessitates a combined pharmacological and surgical approach. Anti-tumor necrosis factor (anti-TNF) therapy, particularly infliximab, has been shown to be very effective for both perianal and internal fistulising CD. Nevertheless, current data suggest that sustained remission and long-term complete fistula healing can be achieved in only 30% to 50% of patients. Moreover, these percentages refer mostly to clinical rather than deep remission, defined as endoscopic and radiologic remission, which is quickly emerging as the preferred goal of therapy. Unfortunately, the therapeutic options for perianal fistulising CD are still limited. As such, it would be of great value to be able to predict, and more importantly, prevent treatment failure in these patients by early and continued optimization of anti-TNF therapy. Similar to ulcerative colitis and luminal CD, recent data demonstrate that higher infliximab concentrations are associated with better clinical outcomes in patients with perianal fistulising CD. This suggests that therapeutic drug monitoring and a treat-to-trough therapeutic approach may emerge as the new standard of care for optimizing anti-TNF therapy in patients with perianal fistulising CD.

Primary and secondary nonresponse to infliximab: mechanisms and countermeasures

INTRODUCTION

Primary and secondary non-response to infliximab are common in patients with inflammatory bowel disease and remain a management challenge in clinical practice. Areas covered: This article describes the epidemiology, mechanisms and risk factors for primary and secondary nonresponse to infliximab in patients with inflammatory bowel disease. Data on proactive and reactive therapeutic drug monitoring are examined in this review. An algorithm for evaluation and management of non-response to infliximab is provided. Preventative measures are also discussed. Relevant articles were identified after a literature search using PubMed. Search terms included 'infliximab', 'loss of response', 'immunogenicity', and 'drug monitoring'. References of identified articles were also reviewed to identify additional references. Expert opinion: A common cause for primary and secondary non-response include inadequate dosing of infliximab; inadequate dosing can be identified through assessment of drug and anti-drug antibody levels. Therapeutic drug monitoring should be done in patients losing response to infliximab. Use of drug monitoring proactively is still under debate.