Phase I, II and III Trials in Inflammatory Bowel Diseases: A Practical Guide for the Non-specialist

Navigating the complexities of drug development for inflammatory bowel disease

Inflammatory bowel disease (IBD) - consisting of ulcerative colitis and Crohn's disease - is a complex, heterogeneous, immune-mediated inflammatory condition with a multifactorial aetiopathogenesis. Despite therapeutic advances in this arena, a ceiling effect has been reached with both single-agent monoclonal antibodies and advanced small molecules. Therefore, there is a need to identify novel targets, and the development of companion biomarkers to select responders is vital. In this Perspective, we examine how advances in machine learning and tissue engineering could be used at the preclinical stage where attrition rates are high. For novel agents reaching clinical trials, we explore factors decelerating progression, particularly the decline in IBD trial recruitment, and assess how innovative approaches such as reconfiguring trial designs, harmonizing end points and incorporating digital technologies into clinical trials can address this. Harnessing opportunities at each stage of the drug development process may allow for incremental gains towards more effective therapies.

Upregulation of Hepatic Glutathione S-Transferase Alpha 1 Ameliorates Metabolic Dysfunction-Associated Steatosis by Degrading Fatty Acid Binding Protein 1

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common metabolic disease of the liver, characterized by hepatic steatosis in more than 5% of hepatocytes. However, despite the recent approval of the first drug, resmetirom, for the management of metabolic dysfunction-associated steatohepatitis, decades of target exploration and hundreds of clinical trials have failed, highlighting the urgent need to find new druggable targets for the discovery of innovative drug candidates against MASLD. Here, we found that glutathione S-transferase alpha 1 (GSTA1) expression was negatively associated with lipid droplet accumulation in vitro and in vivo. Overexpression of GSTA1 significantly attenuated oleic acid-induced steatosis in hepatocytes or high-fat diet-induced steatosis in the mouse liver. The hepatoprotective and anti-inflammatory drug bicyclol also attenuated steatosis by upregulating GSTA1 expression. A detailed mechanism showed that GSTA1 directly interacts with fatty acid binding protein 1 (FABP1) and facilitates the degradation of FABP1, thereby inhibiting intracellular triglyceride synthesis by impeding the uptake and transportation of free fatty acids. Conclusion: GSTA1 may be a good target for the discovery of innovative drug candidates as GSTA1 stabilizers or enhancers against MASLD.

Maintenance of clinical remission with biologics and small molecules in inflammatory bowel disease according to trial design: Meta-analysis

BACKGROUND AND AIMS

Design of randomised controlled trials (RCTs) examining maintenance of clinical remission in inflammatory bowel disease (IBD) varies, with some trials re-randomising patients who have responded to active drug during induction to either active drug or placebo and others treating patients through with active drug or placebo from baseline. Whether this influences therapeutic gain of drug over placebo is unknown.

METHODS

We searched the literature to January 2023 for maintenance of remission trials of biologics or small molecules versus placebo in IBD. We extracted maintenance of remission rates according to trial design; either trials re-randomising patients or trials treating patients through. We pooled data in a meta-analysis for all patients, and according to type of IBD. We calculated the number needed to treat (NNT), with a 95% confidence interval (CI), to assess therapeutic gain of active drug over placebo according to trial design.

RESULTS

We identified 37 maintenance of remission trials (12,075 patients). Rates of maintenance of clinical remission were higher (41.9% with active drug, versus 20.3% with placebo), and NNT lowest (5; 95% CI 4-6), in trials re-randomising patients compared with those treating through (maintenance of remission rate 30.9% with active drug versus 14.6% with placebo, NNT = 7; 95% CI 5-9). Results were similar when trials were analysed according to IBD type but were more marked in ulcerative colitis RCTs (maintenance of remission rates in re-randomised trials 39.4% with active drug versus 17.8% with placebo, NNT = 5; 95% CI 3-7; treat-through trials 27.3% with active drug versus 11.9% with placebo, NNT = 7; 95% CI 5-11.5).

CONCLUSION

Trials re-randomising patients had generally higher maintenance of remission rates, lower NNTs, and greater therapeutic gains over placebo.

Clinical remission in paired phase two and three studies in inflammatory bowel disease: a systematic review with meta-analysis

Discrepancies in phase two and three studies can result in significant patient and financial burden, as well as the nonapproval of potentially efficacious drugs. We aimed to determine whether this discrepancy exists for clinical trials in inflammatory bowel disease (IBD). Electronic databases (MEDLINE and Embase) and clinical trial repositories were searched from 1 January 1946 to 12 March 2021, for paired phase two and three studies of advanced therapies for Crohn's disease and ulcerative colitis. The primary outcome was to compare clinical remission rates between paired phase two and three studies for Crohn's disease and ulcerative colitis. Multivariable mixed-model meta-analysis was performed to calculate odds ratios (OR) with 95% confidence intervals (CI). The Cochrane risk-of-bias tool was used to grade the risk of bias. Of 2642 studies, 29 were included. Fifteen were phase three, 11 were phase two, one was phase one/two, and two were phase two/three. There were no differences in clinical remission rates between phase two and three studies for Crohn's disease (OR, 1.07; 95% CI, 0.86-1.34; P = 0.54) and ulcerative colitis (OR, 0.81; 95% CI, 0.48-1.36; P = 0.43). Furthermore, there was a lack of any appreciable differences in study characteristics, inclusion criteria and patient demographics among paired phase two and three studies. Most studies were considered low risk of bias. Overall, paired phase two and three studies demonstrate similar clinical remission rates for advanced therapies in IBD. Whether this applies to newer outcomes, such as endoscopic and mucosal healing remains to be determined.

Tofacitinib and newer JAK inhibitors in inflammatory bowel disease-where we are and where we are going

Inflammatory bowel diseases, comprising ulcerative colitis (UC) and Crohn's disease, are chronic, immune-mediated and progressive inflammatory disorders affecting the gastrointestinal tract. Tofacitinib is the first oral small-molecule Janus kinase (JAK) inhibitor licensed and approved by the National Institute for Health and Care Excellence (NICE) for use in moderately-to-severely active UC after intolerance, inadequate response, or loss of response to conventional treatment or biologic therapy. The pivotal OCTAVE studies demonstrated the efficacy and safety of tofacitinib for the induction and maintenance of remission in UC. A growing body of evidence from real-world data supports the positive clinical and endoscopic benefits observed with tofacitinib treatment in the OCTAVE trials. This narrative review summarizes the current literature regarding the mechanism of action of tofacitinib, data from registrational trials, emerging real-world evidence, and an overview of the most recent safety evidence. We explore evolving treatment paradigms, including the use of tofacitinib in the COVID-19 era, pregnancy and extraintestinal manifestations, as well as the emerging concept of combining tofacitinib with biological therapy. We will also present a brief overview of the next generation of JAK inhibitors in the pipeline.

Adaptive Designs: Lessons for Inflammatory Bowel Disease Trials

In recent decades, scientific research has considerably evolved in the field of inflammatory bowel diseases (IBD) and clinical studies have become increasingly complex, including new outcomes, different study populations, and additional techniques of re-randomization and centralized control. In this context, randomized clinical trials are the gold standard for new drugs’ development. However, traditional study designs are time-consuming, expensive, and only a small percentage of the tested therapies are approved. For this reason, a new study design called “adaptive design” has been introduced, allowing to accumulate data during the study and to make predefined adjustments based on the results of scheduled interim analysis. Our aim is to clarify the advantages and drawbacks of adaptive designs in order to properly interpret study results and to identify their role in upcoming IBD trials.

Clinical Trials [and Tribulations]: The Immediate Effects of COVID-19 on IBD Clinical Research Activity in the UK

There have been immediate and profound impacts of SARS-CoV-2 and COVID-19 on health care services worldwide, with major consequences for non COVID-19 related health care. Alongside efforts to reconfigure services and enable continued delivery of safe clinical care for patients with IBD, consideration must also be given to management of IBD research activity. In many centres there has been an effective shutdown of IBD clinical trial activity as research sites have switched focus to either COVID-19 related research or clinical care only. As a result, the early termination of trial programmes, and loss of potentially effective therapeutic options for IBD, has become a real and worrying prospect. Moreover, in many countries research activity has become embedded into clinical care-with clinical trials often providing access to new therapies or strategies-which would otherwise not have been available in standard clinical pathways. This pandemic has significant implications for the design, conduct, analysis, and reporting of clinical trials in IBD. In this Viewpoint, we share our experiences from a clinical and academic perspective in the UK, highlighting the early challenges encountered, and consider implications for patients and staff at research sites, sponsors, research ethics committees, funders, and regulators. We also offer potential solutions both for now and for when we enter a recovery phase from the pandemic.