Systematic review with meta-analysis: the effects of immunomodulator or biological withdrawal from mono- or combination therapy in inflammatory bowel disease

Interrupting inflammatory bowel disease therapy: why, who, when and how to consider medication holidays

INTRODUCTION

Medication holidays in inflammatory bowel disease (IBD) offer a potential means to balance disease management, costs, and quality of life. This concept is increasingly relevant in light of the chronic nature of IBD, the cumulative side effects associated with long-term pharmacotherapy, and the evolving treatment landscape that now includes a large armamentarium of effective induction, maintenance, and rescue therapies paired with disease monitoring tools that enable early intervention.

AREAS COVERED

This review critically examines the rationale, implementation, and risks of medication holidays in IBD. Recent evidence is reviewed to help guide the risks of relapse involved with cessation of therapy. The selection criteria for patients, the necessary monitoring protocols, and strategies for managing potential relapses are outlined.

EXPERT OPINION

Despite the potential benefits, medication holidays in IBD involve significant risks and require careful patient selection and active management. Current research highlights a need for improved predictive models and a deeper understanding of patient-specific outcomes and consequences. The future of medication holidays will depend heavily on advancements in noninvasive monitoring technologies and more personalized approaches to therapy. Ultimately, establishing clearer guidelines for safely conducting medication holidays will be crucial in integrating this strategy into routine clinical practice.

Discontinuation of therapy in inflammatory bowel disease: Current views

The timely introduction and adjustment of the appropriate drug in accordance with previously well-defined treatment goals is the foundation of the approach in the treatment of inflammatory bowel disease (IBD). The therapeutic approach is still evolving in terms of the mechanism of action but also in terms of the possibility of maintaining remission. In patients with achieved long-term remission, the question of de-escalation or discontinuation of therapy arises, considering the possible side effects and economic burden of long-term therapy. For each of the drugs used in IBD (5-aminosalycaltes, immunomodulators, biological drugs, small molecules) there is a risk of relapse. Furthermore, studies show that more than 50% of patients who discontinue therapy will relapse. Based on the findings of large studies and meta-analysis, relapse of disease can be expected in about half of the patients after therapy withdrawal, in case of monotherapy with aminosalicylates, immunomodulators or biological therapy. However, longer relapse-free periods are recorded with withdrawal of medication in patients who had previously been on combination therapies immunomodulators and anti-tumor necrosis factor. It needs to be stressed that randomised clinical trials regarding withdrawal from medications are still lacking. Before making a decision on discontinuation of therapy, it is important to distinguish potential candidates and predictive factors for the possibility of disease relapse. Fecal calprotectin level has currently been identified as the strongest predictive factor for relapse. Several other predictive factors have also been identified, such as: High Crohn's disease activity index or Harvey Bradshaw index, younger age (< 40 years), longer disease duration (> 40 years), smoking, young age of disease onset, steroid use 6-12 months before cessation. An important factor in the decision to withdraw medication is the success of re-treatment with the same or other drugs. The decision to discontinue therapy must be based on individual approach, taking into account the severity, extension, and duration of the disease, the possibility of side adverse effects, the risk of relapse, and patient's preferences.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

De-escalation of Therapy in Patients with Quiescent Inflammatory Bowel Disease

Inflammatory bowel disease is a chronic disease of unknown origin that requires long-term treatment. The optical duration of maintenance treatment once remission has been achieved remains unclear. When discussing a de-escalation strategy, not only the likelihood of relapse but also, the outcome of retreatment for relapse after de-escalation should be considered. Previous evidence has demonstrated controversial results for risk factors for relapse after de-escalation due to the various definitions of remission and relapse. In fact, endoscopic or histologic remission has been suggested as a treatment target; however, it might not always be indicative of a successful drug withdrawal. For better risk stratification of relapse after de-escalation, it may be necessary to evaluate both the current and previous treatments. Following de-escalation, biomarkers should be closely monitored. In addition to the risk of relapse, a comprehensive understanding of the overall outcome, such as the long-term safety, patient quality of life, and impact on healthcare costs, is necessary. Therefore, a shared decision-making with patients on a case-by-case basis is imperative.

Evidence-Based Approach to the Discontinuation of Immunomodulators or Biologics in Inflammatory Bowel Disease

BACKGROUND

Biologics and immunomodulators are key drugs in the long-term treatment of inflammatory bowel diseases, while they may negatively impact patients' quality of life due to concerns of adverse events, need for frequent hospital visits, and medical expenses. The basic concept of drug withdrawal should be based on the risk of relapse and the efficacy of re-treatment. Considering a number of patients may relapse even if treatment is continued, the disadvantage of discontinuation should be recognized not by all relapse after discontinuation, but by the increase in relapse.

SUMMARY

Discontinuation of immunomodulator monotherapy is associated with an increased risk of relapse. However, prolonged remission might be an indication of withdrawal, concerning the long-term adverse effect including lymphoma and nonmelanoma skin cancers. When considering discontinuation from combination therapy of anti-tumor necrosis factor (TNF) agents with immunomodulators, therapeutic drug monitoring may be useful to understand the pharmacokinetic effect. However, recent randomized controlled trials, as well as large-scale observational studies, demonstrated that discontinuation of anti-TNF agents, but not of immunomodulators, resulted in a significantly higher risk of relapse even in deep remission. Therefore, discontinuation of anti-TNF agents should be considered with caution and close monitoring combined with fecal calprotectin may be necessary. On the other hand, evidence of not only short-term relapse rate but of the true long-term influence on the patient's quality of life should be clarified by a multidimensional approach.

KEY MESSAGES

Discontinuation of treatment should be implemented based on shared decision-making with careful interpretation of evidence and the condition.

Thiopurines in Inflammatory Bowel Disease. How to Optimize Thiopurines in the Biologic Era?

Thiopurines have been a cornerstone in the treatment of inflammatory bowel disease (IBD). Although they have been used for more than 50 years, there are still some unsolved issues about their efficacy and, also, some safety concerns, mainly the risk of myelosuppression and life-threatening lymphoproliferative disorders. Furthermore, the development of biological therapy raises the question whether there is still a role for thiopurines in the IBD treatment algorithm. On the other hand, limited cost and wide availability make thiopurines a reasonable option in settings of limited resources and increasing prevalence of IBD. In fact, there is a growing interest in optimizing thiopurine therapy, since pharmacogenomic findings suggest that a personalized approach based on the genotyping of some molecules involved in its metabolism could be useful to prevent side effects. Polymorphisms of thiopurine methyltransferase enzyme (TPMT) that result in low enzymatic activity have been associated with an increased risk of myelotoxicity, especially in Caucasians; however, in Asians it is assumed that the variants of nudix hydrolase 15 (NUDT15) are more relevant in the development of toxicity. Age is also important, since in elderly patients the risk of complications seems to be increased. Moreover, the primo-infection of Epstein Barr virus and cytomegalovirus under thiopurine treatment has been associated with severe lymphoproliferative disorders. In addition to assessing individual characteristics that may influence thiopurines treatment outcomes, this review also discusses other strategies to optimize the therapy. Low-dose thiopurines combined with allopurinol can be used in hypermethylators and in thiopurine-related hepatotoxicity. The measurement of metabolites could be useful to assess compliance, identify patients at risk of adverse events and also facilitating the management of refractory patients. Thioguanine is also a rescue therapy in patients with toxicity related to conventional thiopurine therapy. Finally, the current indications for thiopurines in monotherapy or in combination with biologics, as well as the optimal duration of treatment, are also reviewed.

Combination Immunotherapy Use and Withdrawal in Pediatric Inflammatory Bowel Disease-A Review of the Evidence

Evidence-based guidelines have been developed outlining the concomitant use of anti-tumor necrosis factor alpha (anti-TNF) agents and immunomodulators including azathioprine (AZA) and methotrexate (MTX) in both adult and pediatric populations. However, there exists a paucity of data guiding evidence-based strategies for their withdrawal in pediatric patients in sustained remission. This narrative review focuses on the available pediatric evidence on this question in the context of what is known from the larger body of evidence available from adult studies. The objective is to provide clarity and practical guidance around who, what, when, and how to step down pediatric patients with inflammatory bowel disease (IBD) from combination immunotherapy. Outcomes following withdrawal of either of the two most commonly used anti-TNF therapies [infliximab (IFX) or adalimumab (ADA)], or immunomodulator therapies, from a combination regimen are examined. Essentially, a judicious approach must be taken to identify a significant minority of patients who would benefit from treatment rationalization. We conclude that step-down to anti-TNF (rather than immunomodulator) monotherapy after at least 6 months of sustained clinical remission is a viable option for a select group of pediatric patients. This group includes those with good indicators of mucosal healing, low or undetectable anti-TNF trough levels, lack of predictors for severe disease, and no prior escalation of anti-TNF therapy. Transmural healing and specific human leukocyte antigen (HLA) typing are some of the emerging targets and tools that may help facilitate improved outcomes in this process. We also propose a simplified evidence-based schema that may assist in this decision-making process. Further pediatric clinical studies are required to develop the evidence base for decision-making in this area.