Therapeutic Drug Monitoring and Outcome of Infliximab Therapy in Pediatric Onset Inflammatory Bowel Disease

Early infliximab trough levels in paediatric IBD patients predict sustained remission

Background

Exposure-response studies have shown that higher infliximab concentrations are associated with better outcomes in inflammatory bowel disease. There is little agreement about the optimal time to measure infliximab levels in children.

Objectives

We aimed to evaluate whether trough levels at week 6 or week 14 predict sustained remission. The secondary aim was to define target trough levels at weeks 6 and 14.

Design

We used routinely collected electronic healthcare data of 70 anti-tumour necrosis factor naïve children with inflammatory bowel disease treated with a standard infliximab induction- and variable maintenance scheme.

Methods

Trough levels and blood and faecal markers for disease activity were measured before every infliximab administration. Sustained remission was defined as the absence of symptoms and low inflammatory markers between weeks 26 and 52 after the start of infliximab therapy. Optimal infliximab levels at weeks 6 and 14 were determined using the receiver operating characteristic curve.

Results

The median infliximab level at week 6 was not significantly higher in children who achieved sustained remission compared to those who did not (16.9 mg/L versus 12.0 mg/L; p = 0.058) but the median infliximab level at week 14 was significantly higher in those with sustained remission (7.7 mg/L versus 3.8 mg/L; p = 0.006). The area under the receiver operating characteristics curves at weeks 6 and 14 to predict sustained remission was 0.67 (95% CI 0.51-0.83) and 0.75 (95% CI 0.60-0.90), respectively. Target trough levels at weeks 6 and 14 were ⩾13.2 and ⩾6.9 mg/L, respectively.

Conclusion

An infliximab measurement at week 14 with a target through level ⩾6.9 mg/L best predicted sustained remission.

Collision Induced Unfolding Enables the Quantitation of Isomass Biotherapeutics in Complex Biological Matrices

Quantitative mass spectrometry has been widely used to evaluate the concentrations of molecules within a variety of biological matrices. Typically, such quantitative mass spectrometry analyses are predicated upon the production of mass-resolved precursor or fragment ions, leading to challenges surrounding the quantification of isomeric or conformationally distinct analytes. As such, new approaches are required for the label-free quantification of isomass proteins. Native ion-mobility MS (nIM-MS) in combination with collision induced unfolding (CIU) is a potentially enabling approach for such quantitative mass spectrometry methods as the technique can rapidly separate and detect many biomacromolecule isoforms. CIU uses collisional activation to capture the unfolding trajectory of ions in the gas phase, producing different intermediate structures that can be leveraged to distinguish protein structures that exhibit identical sizes at lower energies. Here we describe the deployment of quantitative CIU methodology to measure the concentrations of isomass pairs of biotherapeutics and sequence homologues in both standard and biological matrices. Our results cover three antibody pairs and include examples of mixed therapies where multiple biologics are commonly provided to patients. In all cases, CIU enables the production of resolved features for each antibody mixture probed, producing calibration curves with correlation coefficients ranging from 0.92 to 0.99, limits of detection ranging from 300 to 5000 nM and sensitivities ranging from 8.7 × 10-5 nM-1 to 6 × 10-3 μM-1. We conclude our report by projecting the future utility of CIU-enabled quantitative MS methods.

Pharmacologic Management of Monogenic and Very Early Onset Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is treated with a variety of immunomodulating and immunosuppressive therapies; however, for the majority of cases, these therapies are not targeted for specific disease phenotypes. Monogenic IBD with causative genetic defect is the exception and represents a disease cohort where precision therapeutics can be applied. With the advent of rapid genetic sequencing platforms, these monogenic immunodeficiencies that cause inflammatory bowel disease are increasingly being identified. This subpopulation of IBD called very early onset inflammatory bowel disease (VEO-IBD) is defined by an age of onset of less than six years of age. Twenty percent of VEO-IBDs have an identifiable monogenic defect. The culprit genes are often involved in pro-inflammatory immune pathways, which represent potential avenues for targeted pharmacologic treatments. This review will provide an overview of the current state of disease-specific targeted therapies, as well as empiric treatment for undifferentiated causes of VEO-IBD.

Medical Management of Pediatric Inflammatory Bowel Disease (PIBD) in the Asia Pacific Region: A Position Paper by the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology, and Nutrition (APPSPGHAN) PIBD Working Group

Pediatric inflammatory bowel disease (PIBD) is rising rapidly in many industrialised and affluent areas in the Asia Pacific region. Current available guidelines, mainly from Europe and North America, may not be completely applicable to clinicians caring for children with PIBD in this region due to differences in disease characteristics and regional resources constraints. This position paper is an initiative from the Asian Pan-Pacific Society for Pediatric Gastroenterology, Hepatology and Nutrition (APPSPGHAN) with the aim of providing an up-to-date, evidence-based approach to PIBD in the Asia Pacific region, taking into consideration the unique disease characteristics and financial resources available in this region. A group of pediatric gastroenterologists with special interest in PIBD performed an extensive literature search covering epidemiology, disease characteristics and natural history, management and monitoring. Gastrointestinal infections, including tuberculosis, need to be excluded before diagnosing IBD. In some populations in Asia, the Nudix Hydrolase 15 (NUD15) gene is a better predictor of leukopenia induced by azathioprine than thiopurine-S-methyltransferase (TPMT). The main considerations in the use of biologics in the Asia Pacific region are high cost, ease of access, and potential infectious risk, especially tuberculosis. Conclusion: This position paper provides a useful guide to clinicians in the medical management of children with PIBD in the Asia Pacific region.

Acute Neurological Involvement after Donor Lymphocyte Infusion for Post-Transplant Viral Infection: The Same Pattern of Novel Cancer Immunotherapy-Related CNS Toxicity?

Early post-transplant is the critical phase for the success of hematopoietic stem cell transplantation (HSCT). New viral infections and the reactivations associated with complete ablation of the recipient's T-cell immunity and inefficient reconstitution of the donor-derived system represent the main risks of HSCT. To date, the pharmacological treatments for post-HSCT viral infection-related complications have many limitations. Adoptive cell therapy (ACT) represents a new pharmacological strategy, allowing us to reconstitute the immune response to infectious agents in the post-HSC period. To demonstrate the potential advantage of this novel immunotherapy strategy, we report three cases of pediatric patients and the respective central nervous system complications after donor lymphocyte infusion.

Therapeutic drug monitoring of biologics in inflammatory bowel disease: unmet needs and future perspectives

Therapeutic drug monitoring (TDM) has emerged as a useful tool for optimising the use of biologics, and in particular anti-tumour necrosis factor (anti-TNF) therapy, in inflammatory bowel disease (IBD). However, challenges remain and are hindering the widespread implementation of TDM in clinical practice. These barriers include identification of the optimal drug concentration to target, the lag time between sampling and results, and the proper interpretation of anti-drug antibody titres among different assays. Solutions to overcome these barriers include the harmonisation of TDM assays and the use of point-of-care testing. Other unmet needs include well designed prospective studies and randomised controlled trials focusing on proactive TDM, particularly during induction therapy. Future studies should also investigate the utility of TDM for biologics other than anti-TNF therapies in both IBD and other immune-mediated inflammatory diseases such as rheumatoid arthritis and psoriasis, and the use of pharmacokinetic modelling dashboards and pharmacogenetics towards individual personalised medicine.

Therapy outcome related to adalimumab trough levels in pediatric patients with inflammatory bowel disease

OBJECTIVES

We evaluated the relationship between serum concentration and efficacy of adalimumab (ADA), an anti-tumor necrosis factor-alpha agent, in pediatric patients with inflammatory bowel disease (PIBD).

MATERIALS AND METHODS

This retrospective cross-sectional study traced 75 patients with PIBD (Crohn's disease, n = 57) treated with ADA at two tertiary centers in Finland in 2012-2018. Drug levels and drug antibody titers were chart-reviewed, and the treatment continuation rate of ADA therapy was evaluated. We also assessed the impact of trough levels in the first 3 months on the continuation of ADA within one year of therapy.

RESULTS

ADA was introduced at a median age of 13.4 years, and the median disease duration was 2.7 years. During the first year, 22 patients (29%) discontinued ADA due to either loss of response (20%, n = 15) or anti-drug antibody formation (5.3%, n = 4). Regarding trough levels in the first 3 months, 9/16 patients (56%) with trough levels <5 mg/L and 12/20 (60%) with trough levels <7.5 mg/L at 3 months discontinued the therapy by the end of the first year. In comparison, only 8/32 patients (25%) with trough levels >7.5 mg/L at 3 months discontinued treatment during the first year (p = .005). At the last follow-up (median 1.5 years), 52% of the 75 patients were on maintenance therapy and had a median trough level of 8.8 mg/L.

CONCLUSION

Higher trough levels in the first 3 months of adalimumab treatment are associated with lower rates of discontinuation due to loss of response during the first year.

Biosimilar Interchangeability and Emerging Treatment Strategies for Inflammatory Bowel Diseases: A Commentary

This commentary summarizes a collection of key references published within the last ten years, and identifies pharmacologic research directions to improve treatment access and success through greater biosimilar or “follow-on” biologic utilization combined with other targeted small molecule agents that possess unique pathophysiologic mechanisms for inflammatory bowel diseases (IBD) in adult and pediatric patients. Since they are not identical to the originator or reference biologic agent, all biosimilars are not generically equivalent. However, in the US and other countries, they are considered therapeutically interchangeable if the manufacturer has demonstrated no clinically meaningful differences from the reference product. Comparisons of different clinical initiation and switching scenarios are discussed with reference to interchangeability, immunogenicity, nocebo effect, cost effectiveness, and time courses for discontinuation rates.