Combination therapy for inflammatory bowel disease

Combining mechanistic modeling with machine learning as a strategy to predict inflammatory bowel disease clinical scores

Disease activity scores are efficacy endpoints in clinical trials of inflammatory bowel disease (IBD) therapies. Crohn's disease activity index (CDAI), Mayo endoscopic score (MES) and Mayo score are frequently used in clinical trials. They rely on either the physician's observation of the inflammatory state of the patient's gastrointestinal tissue alone or combined with the patient's subjective evaluation of general wellbeing. Given the importance of these scores in evaluating the efficacy of drug treatment and disease severity, there has been interest in developing a computational approach to reliably predict these scores. A promising approach is using mechanistic models such as quantitative systems pharmacology (QSP) which simulate the mechanisms of the disease and its modulation by the drug pharmacology. However, extending QSP model simulations to clinical score predictions has been challenging due to the limited availability of gut biopsy measurements and the subjective nature of some of the evaluation criteria for these scores that cannot be described using mechanistic relationships. In this perspective, we examine details of IBD disease activity scores and current progress in building predictive models for these scores (such as biomarkers for disease activity). Then, we propose a method to leverage simulated markers of inflammation from a QSP model to predict IBD clinical scores using a machine learning algorithm. We will demonstrate how this combined approach can be used to (1) explore mechanistic insights underlying clinical observations; and (2) simulate novel therapeutic strategies that could potentially improve clinical outcomes.

Analysis of the risk of oncological adverse events associated with infliximab in combination with azathioprine compared to monotherapy: insights from the FAERS database

Objective

This study aimed to evaluate the risk of tumor formation with infliximab or azathioprine monotherapy versus their combination, using the FDA Adverse Event Reporting System (FAERS) database.

Methods

Data were extracted from the FAERS database for patients treated with infliximab, azathioprine, and combination therapy from Q1 2004 to Q2 2024. Signal mining employed methods such as Reported Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Multiple Gamma-Poisson Scaling Assessment (MGPSA) and Bayesian Confidence Interval Progressive Neural Network (BCPNN).

Results

Our analysis of the FAERS database revealed that the highest number of reported cases involved skin-related tumors, both individually and in combination. In terms of sex, the risk of cancer was higher in men compared to women in the infliximab-only and combination groups; however, no sex difference was observed in the azathioprine-only group. Regarding age, we noted an increasing incidence of adverse tumor events in middle-aged and elderly individuals compared to minors, except in the azathioprine group, where age was not identified as an independent risk factor. Additionally, body weight was not found to be an independent risk factor in any of the three medication groups. After controlling for age, sex, and body weight, combination therapy did not increase the risk of tumor development compared to the azathioprine group alone. In contrast, for patients using infliximab alone, combination therapy not only did not elevate the risk of tumor development but also appeared to reduce it. The results of the Weber distribution suggest a random failure-type profile for the infliximab and azathioprine-only group, while an early failure-type profile was observed for the combination therapy. Furthermore, we analyzed the median time to onset and cumulative incidence rates, revealing no significant differences in median time to tumor onset or cumulative incidence rates between the combination therapy and the single agent.

Conclusion

After adjusting for age, sex, and body weight, combination therapy did not significantly increase tumor development risk compared to the azathioprine-only group. Additionally, in patients on infliximab monotherapy, combination therapy appeared to reduce the risk of tumor development.

Using Automated Machine Learning to Predict Necessary Upcoming Therapy Changes in Patients With Psoriasis Vulgaris and Psoriatic Arthritis and Uncover New Influences on Disease Progression: Retrospective Study

BACKGROUND

Psoriasis vulgaris (PsV) and psoriatic arthritis (PsA) are complex, multifactorial diseases significantly impacting health and quality of life. Predicting treatment response and disease progression is crucial for optimizing therapeutic interventions, yet challenging. Automated machine learning (AutoML) technology shows promise for rapidly creating accurate predictive models based on patient features and treatment data.

OBJECTIVE

This study aims to develop highly accurate machine learning (ML) models using AutoML to address key clinical questions for PsV and PsA patients, including predicting therapy changes, identifying reasons for therapy changes, and factors influencing skin lesion progression or an abnormal Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score.

METHODS

Clinical study data from 309 PsV and PsA patients were extensively prepared and analyzed using AutoML to build and select the most accurate predictive models for each variable of interest.

RESULTS

Therapy change at 24 weeks follow-up was modeled using the extreme gradient boosted trees classifier with early stopping (area under the receiver operating characteristic curve [AUC] of 0.9078 and logarithmic loss [LogLoss] of 0.3955 for the holdout partition). Key influencing factors included the initial systemic therapeutic agent, the Classification Criteria for Psoriatic Arthritis score at baseline, and changes in quality of life. An average blender incorporating three models (gradient boosted trees classifier, ExtraTrees classifier, and Eureqa generalized additive model classifier) with an AUC of 0.8750 and LogLoss of 0.4603 was used to predict therapy changes for 2 hypothetical patients, highlighting the significance of these factors. Treatments such as methotrexate or specific biologicals showed a lower propensity for change. An average blender of a random forest classifier, an extreme gradient boosted trees classifier, and a Eureqa classifier (AUC of 0.9241 and LogLoss of 0.4498) was used to estimate PASI (Psoriasis Area and Severity Index) change after 24 weeks. Primary predictors included the initial PASI score, change in pruritus levels, and change in therapy. A lower initial PASI score and consistently low pruritus were associated with better outcomes. BASDAI classification at onset was analyzed using an average blender of a Eureqa generalized additive model classifier, an extreme gradient boosted trees classifier with early stopping, and a dropout additive regression trees classifier with an AUC of 0.8274 and LogLoss of 0.5037. Influential factors included initial pain, disease activity, and Hospital Anxiety and Depression Scale scores for depression and anxiety. Increased pain, disease activity, and psychological distress generally led to higher BASDAI scores.

CONCLUSIONS

The practical implications of these models for clinical decision-making in PsV and PsA can guide early investigation and treatment, contributing to improved patient outcomes.

Glycosides as Potential Medicinal Components for Ulcerative Colitis: A Review

Ulcerative colitis (UC) is a chronic, non-specific disease of unknown etiology. The disease develops mainly in the rectum or colon, and the main clinical symptoms include abdominal pain, diarrhea, and purulent bloody stools, with a wide variation in severity. The specific causative factors and pathogenesis of the disease are not yet clear, but most scholars believe that the disease is caused by the interaction of genetic, environmental, infectious, immune, and intestinal flora factors. As for the treatment of UC, medications are commonly used in clinical practice, mainly including aminosalicylates, glucocorticoids, and immunosuppressive drugs. However, due to the many complications associated with conventional drug therapy and the tendency for UC to recur, there is an urgent need to discover new, safer, and more effective drugs. Natural compounds with biodiversity and chemical structure diversity from medicinal plants are the most reliable source for the development of new drug precursors. Evidence suggests that glycosides may reduce the development and progression of UC by modulating anti-inflammatory responses, inhibiting oxidative stress, suppressing abnormal immune responses, and regulating signal transduction. In this manuscript, we provide a review of the epidemiology of UC and the available drugs for disease prevention and treatment. In addition, we demonstrate the protective or therapeutic role of glycosides in UC and describe the possible mechanisms of action to provide a theoretical basis for preclinical studies in drug development.

Advances in Lipid-Based Codelivery Systems for Cancer and Inflammatory Diseases

Combination therapy targeting multiple therapeutic targets is a favorable strategy to achieve better therapeutic outcomes in cancer and inflammatory diseases. Codelivery is a subfield of drug delivery that aims to achieve combined delivery of diverse therapeutic cargoes within the same delivery system, thereby ensuring delivery to the same site and providing an opportunity to tailor the release kinetics as desired. Among the wide range of materials being investigated in the design of codelivery systems, lipids have stood out on account of their low toxicity, biocompatibility, and ease of formulation scale-up. This review highlights the advances of the last decade in lipid-based codelivery systems focusing on the codelivery of drug-drug, drug-nucleic acid, nucleic acid-nucleic acid, and protein therapeutic-based combinations for targeted therapy in cancer and inflammatory diseases.

Pre-clinical Investigation of Protective Effect of Nutraceutical D-Glucosamine on TNBS-induced Colitis

The level of precursors involved in the biosynthesis of glycosaminoglycan (GAG), glucosamine synthase, and N-acetyl glucosamine (NAG), are significantly reduced in inflammatory bowel disease (IBD). This results in deficient GAG content in mucosa, which eventually disrupts the gut wall integrity, provoking abnormal immunological responses. This is characterized by colossal liberation of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukins (IL), and reactive oxygen species provoking colonic inflammation. D-glucosamine (D-GLU) is reported to suppress oxidative stress, and pro-inflammatory cytokines and acts as a starting material for biosynthesis of NAG. The potential of D-GLU and its combination with mesalamine (5-ASA) was investigated in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-instigated IBD in Wistar rats. Standard and test drugs were given orally for five days to separate groups of rats. Colonic inflammation was evaluated by disease activity score rate (DASR), colon/body weight ratio, colon length, diameter, colon pH, histological injury and score. Inflammatory biomarkers IL-1β, TNF-α, along with reduced glutathione (GSH), and malondialdehyde (MDA) were assessed. Combination of D-GLU +5-ASA significantly ameliorated severity of colonic inflammation by lowering DASR (P < 0.001) and colon/body weight ratio (P < 0.001), restored the colonic architecture and suppressed the histopathological score (P < 0.001), along with the absence of major adverse reactions. The combination suppressed the levels of inflammatory markers (P < 0.001) and MDA (P < 0.001) while enhancing GSH level (P < 0.001). In comparison to individual 5-ASA and D-GLU, combination of drugs significantly diminished colitis severity through their combined anti-inflammatory and antioxidant effects by acting on multiple targets simultaneously. The combination holds remarkable potential in the management of IBD.

Dual Biologic or Small Molecule Therapy for Treatment of Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

We conducted a systematic review and meta-analysis to summarize emerging data on the safety and effectiveness of dual biologic therapy in combination or with tofacitinib in patients with refractory inflammatory bowel disease (IBD).

METHODS

Through a systematic search of multiple electronic databases through November 9, 2020, we identified cohort studies or case series (>10 patients) reporting the safety and effectiveness of simultaneous use of biologic agents in combination or with tofacitinib in patients with IBD. Rates of adverse events, clinical remission, and endoscopic remission were synthesized using pooled data, and we identified factors associated with successful dual therapy.

RESULTS

We identified 30 studies reporting 288 trials of dual biologic or small molecule therapy in 279 patients (76% Crohn's disease; median duration of treatment 24 weeks (IQR₂₅-IQR₇₅ 1332)). The main indications for dual therapy included medically refractory IBD (81%) and concurrent extra-intestinal manifestations or rheumatologic disease (12%). The most common combinations of dual therapy included tumor necrosis factor-α antagonists & anti-integrins (48%), ustekinumab & anti-integrins (19%); 61% of patients had previously failed at least one of the two therapies used in combination. Over a median follow-up of 32 weeks (IQR₂₅-IQR₇₅ 24-52), pooled rates of adverse and serious adverse events were 31% (95% CI, 13%-54%) and 6.5% (95% CI, 2.1%-13.1%); pooled rates of clinical and endoscopic remission were 59% (95% CI, 42%-74%), and 34% (95% CI, 23%-46%), respectively. 12% (95% CI, 4%-24%) of patients required surgery. Rates of success were higher in patients on dual therapy due to EIM. Heterogeneity was not significant for endoscopic response (P = .88, I² = 0%), endoscopic remission (P = .44, I² = 0%), and malignancy (P = .87, I² = 0%). However, significant heterogeneity existed for other outcomes.

CONCLUSIONS

Dual biologic or small molecule therapy may be a possible option in highly selected, refractory IBD patients at specialized centers. Higher quality combination of therapies with a significant improvement in the quality of data is required prior to more widespread use.

Use of thiopurines in inflammatory bowel disease: an update

Inflammatory bowel disease (IBD), once considered a disease of the Western hemisphere, has emerged as a global disease. As the disease prevalence is on a steady rise, management of IBD has come under the spotlight. 5-Aminosalicylates, corticosteroids, immunosuppressive agents and biologics are the backbone of treatment of IBD. With the advent of biologics and small molecules, the need for surgery and hospitalization has decreased. However, economic viability and acceptability is an important determinant of local prescription patterns. Nearly one-third of the patients in West receive biologics as the first/initial therapy. The scenario is different in developing countries where biologics are used only in a small proportion of patients with IBD. Increased risk of reactivation of tuberculosis and high cost of the therapy are limitations to their use. Thiopurines hence become critical for optimal management of patients with IBD in these regions. However, approximately one-third of patients are intolerant or develop adverse effects with their use. This has led to suboptimal use of thiopurines in clinical practice. This review article discusses the clinical aspects of thiopurine use in patients with IBD with the aim of optimizing their use to full therapeutic potential.

Impact of the Concomitant Use of Immunomodulator and a Lower Week 8 Partial Mayo Score on the Persistence of Adalimumab in Refractory Ulcerative Colitis

Objective Real-world data of adalimumab (ADA) in the treatment of ulcerative colitis (UC) are scarce. We aimed to study the ADA response rates and predictors of response in UC treatment. Methods This observational, prospective and multi-center study assessed the clinical outcome of refractory UC patients treated with ADA who previously had an inadequate response to either conventional therapies or other anti-TNF antibodies or tacrolimus. The primary endpoint was the proportion of UC patients achieving a clinical response and remission at 8 and 52 weeks. We also evaluated the parameters which were associated with a clinical response at 8 and 52 weeks. Results A total of 35 patients were enrolled from 11 centers. The clinical responses at 8 and 52 weeks were 60.0% and 51.4%, respectively. The clinical remission rates at 8 and 52 weeks were 45.7% and 48.6%, respectively. Positive predictors for week 52 response were combination of ADA with immunomodulator (IM) (OR: 27.229; 95% CI; 1.897-390.76; p=0.015) and a week 8 lower partial Mayo score (OR: 0.406; 95% CI; 0.204-0.809; p=0.010). A receiver operation characteristic curve analysis revealed the optimal week 8 partial Mayo score to be 2.5, therefore a partial Mayo score of ≤2 was a positive predictor for the continuation of ADA. No malignancy or death occurred during this study. Conclusion ADA was effective for inducing and maintaining both a clinical response and remission in patients with refractory UC. It remains possible that the concomitant use of IM and a week 8 partial Mayo score of ≤2 may predict the long-term response of ADA.

From single-target to cellular niche targeting in Crohn's disease: intercepting bad communications

The mainstay of moderate to severe Crohn's disease (CD), anti-TNF treatment, shows no clinical benefit in ∼40% of patients, likely due to incomplete cellular targeting and delayed treatment institution. While single-target therapeutics have been highly effective for some CD patients, substantial limitations with respect to safety, efficacy, and long-term, complete remission remain. Deconvolution of the cellular and molecular circuitry of tissue lesions underscores the importance of combinatorial strategies targeting cellular niches. This review aims to evaluate current therapeutic approaches used to manage CD, and highlight recent advances to our cellular, genetic, and molecular understanding of mechanisms driving pathogenic niche activation in CD. We propose new frameworks outlining that combinatorial therapies, along with serial tissue sampling and studies guided by genetics and genomics, can advance on current treatment approaches and will inform newer strategies upon which we can move towards precision therapeutics in IBD.

Dual Targeted Therapy for the Management of Inflammatory Bowel Disease

The burden of inflammatory bowel disease (IBD) is increasing globally and imposes a high morbidity in patients with IBD. Advances have been made in medical management of IBD with the advent of novel therapies such as the biologics and small molecule drugs (SMDs). However, response to these medications is limited; with only 40% of patients achieving clinical remission at 1 year with a biologic. Hence, medical management of IBD is a rapidly evolving paradigm in which not only are new medications being developed but understanding how, when and in whom to use them is evolving. Dual targeted therapy (DTT), which is the combination of biologics and/or SMDs is an attractive concept as it is theoretically a potent and multidimensional anti-inflammatory treatment strategy. In this review, we present the published literature on the use of DTT and highlight its utility in clinical practice. The majority of studies on DTT are case reports and case series on the combination of dual biologic therapy. From the limited evidence available in patients with IBD, dual biologic therapy may be a safe option for patients with refractory IBD who have failed multiple biologic therapies and to manage extraintestinal manifestation of IBD. There are a handful of reports of combination therapy with a biologic and a SMD in patients with IBD. Further studies and randomized control trials are required to comprehensivretain hereely evaluate the safety and efficacy of DTT in IBD.

Higher risk of tuberculosis in combination therapy for inflammatory bowel disease: A nationwide population-based cohort study in South Korea

Inflammatory bowel disease (IBD) in Asia has become increasingly prevalent. As a treatment of IBD, many immunomodulators and biological agents were introduced and shown to be effective in inducing and maintaining remission. However, many cases with treatment failure were reported. To overcome the failure, combination therapy of immunomodulatory and biologics have emerged, showing better outcomes by optimizing biologic pharmacokinetics and minimizing immunogenicity. Adversely, rates of tuberculosis (TB) have been increased as a result. The aim of this study is to compare the risk of TB according to the therapy using large population data.We used data from the South Korean Health Insurance and Review Agency over the period 2008-2016 and calculated the hazard ratio (HR) for TB in IBD. We compared the risk of TB according to the medication: infliximab only, azathioprine only (AZA), combination of azathioprine and infliximab (CAI), azathioprine monotherapy and infliximab monotherapy (AIM), and azathioprine and infliximab whether simultaneously or separately (AISS).In IBD patients, a total of 249 patients were identified as active TB. After one-to-one matching with age, sex and disease duration, the risks of TB were significantly higher in AZA group (HR, 2.06; 95% CI, 1.35-3.12, P < .001), AIM group (HR, 3.26; 95% CI, 1.18-9.05, P = .02), AISS group (HR, 3.50; 95% CI, 1.92-6.37, P < .001), and CAI group (HR, 5.67; 95% CI, 2.42-10.21, P < .001), and the HR increased gradually in this order. In UC patients, the results were in similar pattern, but this pattern was not observed in CD patients in our study.Our study shows that Korean IBD patients are at risk of TB, and the risk increases with usage of IBD medication; moreover, the risk is the highest if combination therapy is used. These results highlight the importance of screening for TB in IBD patients, especially in combination therapy.

Inflammatory Bowel Disease - Non-biological treatment

Nowadays, non-biological treatments remain valuable approaches among the therapeutic armamentarium of inflammatory bowel disease (IBD). Mesalamine is the core treatment of mild‑to‑moderate ulcerative colitis (UC) and corticosteroids are crucial for the induction of remission of moderate‑to‑severe flares in both UC and Crohn's disease (CD). Even approaches as cyclosporine, tacrolimus, azathioprine, methotrexate, and surgery still have a nuclear position as strategies to induce and/or maintain remission in IBD. Due to their particularities and to the accumulated evidence, each of these strategies conquered peculiar roles in the overall IBD strategy, all of them contributing to better outcomes. This review emphasizes the particular roles that non-biological treatments gained over time: recent mesalamine formulations to increase adhesion rates, higher doses of 5-ASA for high-risk patients, MMX technology to improve drug release and attain higher bowel concentrations, cyclosporine as a bridge to vedolizumab, tacrolimus as a potential alternative to thiopurines or infliximab, azathioprine in combination therapy with infliximab and dubious in monotherapy, and surgery as a mean to a "better end".

Impact of immunomodulator use on treatment persistence in patients with ulcerative colitis: A claims database analysis

BACKGROUND AND AIM

It is unclear how adding an anti-tumor necrosis factor alpha agent to immunomodulator (IM) treatment, as a step-up strategy, affects long-term outcomes in ulcerative colitis. This retrospective study investigated persistence associated with biologic anti-tumor necrosis factor alpha agents combined with IMs versus biologic monotherapy in patients with ulcerative colitis.

METHODS

This was a longitudinal cohort study of patients in the Japan Medical Data Center claims database who had been newly prescribed infliximab or adalimumab as induction (completed) and maintenance (2010-2016). Biologic persistence (i.e. no switch/discontinuation during maintenance) was compared among patients prescribed biologic monotherapy (Bio) and those prescribed a biologic combined with an IM, as step-up (Bio + prior IM) or simultaneously (Bio + IM).

RESULTS

Three hundred and sixty-nine eligible patients were analyzed (233, 78, and 58 in the Bio, Bio + prior IM, and Bio + IM subgroups, respectively). Multivariate analysis showed a lower probability of nonpersistence during maintenance for infliximab-treated patients in the Bio + prior IM versus Bio subgroup (hazard ratio: 0.53; 95% confidence interval: 0.29-0.99; P = 0.045). No such effect was seen in adalimumab-treated patients (P = 0.222) or in the overall population (P = 0.398). The probability of nonpersistence during maintenance in the Bio + IM subgroup was not significantly different from that in the Bio subgroup in either the biologic subpopulation or in the overall population.

CONCLUSIONS

Adding infliximab to an existing IM results in a lower probability of nonpersistence compared with infliximab monotherapy in ulcerative colitis patients. This effect is not seen in adalimumab-treated patients.

Withdrawal of Azathioprine in Inflammatory Bowel Disease Patients Who Sustain Remission: New Risk Factors for Relapse

BACKGROUND

The benefits of immunosuppressants for sustaining remission and preventing flares of IBD are well known. However, optimal timing for withdrawal has not been determined.

AIMS

The objective of this study was to calculate the risk of relapse and predictors after withdrawal of azathioprine (AZA) monotherapy in patients who sustain deep remission.

METHODS

This was a multicenter observational study of patients with IBD in remission whose immunosuppressant had been withdrawn. We recorded demographic variables, disease data, laboratory values, and the results of imaging tests performed at withdrawal and, in patients who relapsed, time to relapse and the efficacy of reintroducing the drug.

RESULTS

Ninety-five patients were included (35 UC and 60 CD). The mean duration of AZA treatment was 87 and 77 months for UC and CD, respectively. Endoscopic remission was evaluated in 23 patients with UC and 35 with CD. After AZA withdrawal, 91% patients with UC and 67% with CD received high doses of salicylates. A total of 26 patients relapsed. The cumulative relapse rate at 5 years was 46% for CD and UC. AZA was reintroduced in 19 patients, of whom 14 responded. Predictors of relapse were corticosteroid dependence, early introduction of AZA (CD), and late introduction of AZA (UC).

CONCLUSIONS

Almost half of the patients in whom AZA was withdrawn were in remission at 5 years. The candidates for withdrawal could be better identified based on corticosteroid dependence, previous surgery, timing of initiation, and indication for AZA.

Higher Mucosal Healing with Tumor Necrosis Factor Inhibitors in Combination with Thiopurines Compared to Methotrexate in Crohn's Disease

BACKGROUND

The differential impact of anti-tumor necrosis factor (anti-TNF) therapy with methotrexate versus thiopurine co-therapy on endoscopic remission remains uncertain.

AIMS

To compare rates of endoscopic remission based on methotrexate or thiopurine co-therapy used with anti-TNF therapy in Crohn's disease.

METHODS

A retrospective observational study at two tertiary centers between 2010 and 2016 compared endoscopic remission rates and persistence on anti-TNF therapy in combination with methotrexate versus thiopurines for at least 3 months.

RESULTS

Of 412 patients on anti-TNF therapy, 278 (67%) received immunomodulator co-therapy for ≥ 3 months and 269 (65%) had complete data for analysis. Methotrexate was used in 77 (29%) and thiopurines in 192 (71%) patients plus either infliximab (156, 58%) or adalimumab (113, 42%), with median follow-up of 2.8 years. The methotrexate group had greater prior immunomodulator intolerance (62% vs 20%, p < 0.01). Endoscopic remission rates were higher in those treated with thiopurine compared to methotrexate co-therapy at 12 m (58% vs 17%, p < 0.01) and at last review (59% vs 40%, p = 0.03). Endoscopic remission rates were higher with thiopurines than methotrexate when combined with adalimumab (49% vs 6%, p < 0.01) but not with infliximab (65% vs 54%, p = 0.09). In multivariate analysis, thiopurine co-therapy, elevated baseline CRP, and therapeutic anti-TNF drug levels were each associated with longer persistence of co-therapy (each p < 0.05). There were no significant differences in adverse events, malignancy or infection rates.

CONCLUSION

In this cohort, anti-TNF and thiopurine co-therapy resulted in higher rates of mucosal healing than methotrexate, the difference is most pronounced with adalimumab and conversely with low-dose methotrexate.

Revisiting the Role of Thiopurines in Inflammatory Bowel Disease Through Pharmacogenomics and Use of Novel Methods for Therapeutic Drug Monitoring

Azathioprine and 6-mercaptopurine, often referred to as thiopurine compounds, are commonly used in the management of inflammatory bowel disease. However, patients receiving these drugs are prone to developing adverse drug reactions or therapeutic resistance. Achieving predefined levels of two major thiopurine metabolites, 6-thioguanine nucleotides and 6-methylmercaptopurine, is a long-standing clinical practice in ensuring therapeutic efficacy; however, their correlation with treatment response is sometimes unclear. Various genetic markers have also been used to aid the identification of patients who are thiopurine-sensitive or refractory. The recent discovery of novel Asian-specific DNA variants, namely those in the NUDT15 gene, and their link to thiopurine toxicity, have led clinicians and scientists to revisit the utility of Caucasian biomarkers for Asian individuals with inflammatory bowel disease. In this review, we explore the limitations associated with the current methods used for therapeutic monitoring of thiopurine metabolites and how the recent discovery of ethnicity-specific genetic markers can complement thiopurine metabolites measurement in formulating a strategy for more accurate prediction of thiopurine response. We also discuss the challenges in thiopurine therapy, alongside the current strategies used in patients with reduced thiopurine response. The review is concluded with suggestions for future work aiming at using a more comprehensive approach to optimize the efficacy of thiopurine compounds in inflammatory bowel disease.

Immune Mechanisms and Pathways Targeted in Type 1 Diabetes

PURPOSE OF REVIEW

The immunosuppressive agent cyclosporine was first reported to lower daily insulin dose and improve glycemic control in patients with new-onset type 1 diabetes (T1D) in 1984. While renal toxicity limited cyclosporine's extended use, this observation ignited collaborative efforts to identify immunotherapeutic agents capable of safely preserving β cells in patients with or at risk for T1D.

RECENT FINDINGS

Advances in T1D prediction and early diagnosis, together with expanded knowledge of the disease mechanisms, have facilitated trials targeting specific immune cell subsets, autoantigens, and pathways. In addition, clinical responder and non-responder subsets have been defined through the use of metabolic and immunological readouts. Herein, we review emerging T1D biomarkers within the context of recent and ongoing T1D immunotherapy trials. We also discuss responder/non-responder analyses in an effort to identify therapeutic mechanisms, define actionable pathways, and guide subject selection, drug dosing, and tailored combination drug therapy for future T1D trials.

Is the pharmaceutical industry's preoccupation with the monotherapy drug model stifling the development of effective new drug therapies?

Drug discovery and development is heavily biased towards the development of monotherapies. Screening, testing, and evaluation of mono-entity drugs are generally much simpler than drug combinations, and are generally easier to get approval from the regulatory authorities for their clinical use. However, monotherapy drugs may not have optimal activity, may have associated toxicities, or may lose activity over time as their target develops resistance. Drug combinations, often developed from existing monotherapies, may have improved efficacy and/or be less toxic. Furthermore, the existing drugs which have lost efficacy due to the development of resistance can often be re-activated by combining them with other chemical entities. Thus, whilst the current climate for drug approval, registration, and clinical use drives the majority of drug development research towards the development of monotherapies, combinations are often a substantial improvement on the original drug. This commentary examines monotherapy and combinational therapy models and discusses the benefits and limitations of each model.