Clinical, Endoscopic, and Safety Placebo Rates in Induction and Maintenance Trials of Crohn's Disease: Meta-Analysis of Randomised Controlled Trials

Interpreting modern randomized controlled trials of medical therapy in inflammatory bowel disease

Treatment options for the medical management of inflammatory bowel disease (IBD) have expanded substantially over the past decade. Multiple classes of advanced therapies, including both monoclonal antibodies and novel oral small molecules, are now available for the treatment of moderately-to-severely active Crohn's disease and ulcerative colitis, highlighted by the approvals of the first IL23p19 antagonists, selective Janus kinase inhibitors and sphingosine-1-phosphate receptor modulators. These advances have been accompanied by the identification of novel targets and the rapid growth in both the number and size of IBD clinical trials. Over a dozen landmark randomized controlled trials (RCTs) have been completed in the past 5 years, including the first head-to-head biologic trials, the first combination biologic studies, and multiple phase III registrational trials of novel compounds with new co-primary and composite end points that will change the treatment landscape for years to come. Importantly, the methodology of RCTs in IBD has evolved substantially, with new trial designs, evaluation of unique patient populations, and different types of efficacy and safety end points being key innovations. In this Review, we provide a comprehensive evaluation of how modern RCTs of IBD medical therapies have evolved and the implications for their appraisal that will help guide the application of these data to clinical practice.

Harms with placebo in trials of biological therapies and small molecules as induction therapy in inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND

Randomised placebo-controlled trials are the gold standard to assess novel drugs in ulcerative colitis and Crohn's disease. However, there might be risks associated with receiving placebo. We aimed to examine the harms associated with receiving placebo in trials of licensed biologics and small molecules for the induction of remission in ulcerative colitis and luminal Crohn's disease in a meta-analysis.

METHODS

We performed a systematic review and meta-analysis. We searched MEDLINE, Embase, Embase Classic, and the Cochrane Central Register of Controlled Trials from database inception to May 30, 2024, for randomised placebo-controlled trials of licensed biologics and small molecules for induction of remission in adults (≥18 years) with moderately to severely active ulcerative colitis or luminal Crohn's disease reporting data on adverse events over a minimum treatment period of 4 weeks. There were no prespecified study exclusion criteria. We extracted summary data and pooled data using a random-effects model for any treatment-emergent adverse event, any drug-related adverse event, infection, worsening of inflammatory bowel disease (IBD) activity, withdrawal due to adverse events, serious adverse events, serious infection, serious worsening of IBD activity, or venous thromboembolic events (VTEs), reporting relative risks (RRs) with 95% CIs. The protocol for this meta-analysis was registered with PROSPERO (CRD42024527341).

FINDINGS

The search identified 10 826 citations, of which 47 trials including 20 987 patients (14 267 [68·0%] receiving active drug and 6720 [32·0%] receiving placebo) were eligible. The risk of any treatment-emergent adverse event was no different with active drug than with placebo (7660/14 267 [53·7%] patients on active drug vs 3758/6720 [55·9%] on placebo; RR 0·97, 95% CI 0·94-1·00; I2 =36%). However, the risks of worsening of IBD activity (563/13 473 [4·2%] vs 530/6252 [8·5%]; 0·48, 0·40-0·59; I2 =54%), withdrawal due to adverse event (401/13 363 [3·0%] vs 299/6267 [4·8%]; 0·62, 0·48-0·79; I2 =46%), serious adverse event (682/14 267 [4·8%] vs 483/6720 [7·2%]; 0·69, 0·59-0·80; I2 =30%), serious infection (140/14 194 [1·0%] vs 91/6647 [1·4%]; 0·67, 0·50-0·89; I2 =0%), serious worsening of IBD activity (187/11 271 [1·7%] vs 189/5056 [3·7%]; 0·45, 0·34-0·60; I2 =27%), or VTEs (13/7542 [0·2%] vs 12/2981 [0·4%]; 0·45, 0·21-0·94; I2 =0%) were all significantly lower with active drug than placebo. Numbers needed to treat with active drug to avoid these potentially serious adverse events ranged from 23 for worsening of IBD activity to 452 for VTEs. 27 randomised controlled trials were judged as low risk of bias across all domains.

INTERPRETATION

Patients with moderately to severely active IBD receiving placebo are more likely to experience significant worsening of IBD activity and some serious adverse events, which might relate to a reduction in risk of these events with active drug. Patients should be counselled about these potential harms, and alternative trial designs to mitigate these harms should be considered.

FUNDING

None.

Upadacitinib Reduces Crohn's Disease Symptoms Within the First Week of Induction Therapy

BACKGROUND & AIMS

Upadacitinib (UPA), an oral Janus kinase inhibitor, is approved to treat moderately to severely active Crohn's disease (CD). Because symptomatic response is an important initial treatment goal for patients, we evaluated the rapidity of symptomatic improvement in patients with CD receiving UPA 45 mg once daily (UPA45) induction therapy.

METHODS

This post hoc analysis included pooled data from 2 phase 3, multicenter, double-blind, 12-week induction trials (U-EXCEL and U-EXCEED) and 1 maintenance trial (U-ENDURE). Daily diary data for the first 15 days of UPA45 or placebo (PBO) treatment were used to analyze improvement in very soft/liquid stool frequency (SF) and abdominal pain score (APS). Clinical outcomes were evaluated at every study visit.

RESULTS

Overall, 1021 patients (n = 674 UPA45; n = 347 PBO) were analyzed. UPA45 demonstrated greater efficacy vs PBO for SF <3 and APS ≤1, providing rapid relief by day 5 or 6, regardless of prior biologic exposure. Mean changes in SF and APS were greater with UPA45 beginning at week 2 (-2.0 and -0.5, respectively; P < .001) and were maintained through week 12 (-3.0 and -1.0, respectively; P < .001) vs PBO. The first achievement of daily SF/APS clinical remission occurred earlier with UPA45 (median, 13 d) vs PBO (median, 32 d), and patients treated with UPA45 showed improved rates of SF/APS clinical remission (21.1% UPA45 vs 8.9% PBO) and clinical response (58.8% UPA45 vs 37.9% PBO) starting at week 2 (both P ≤ .01).

CONCLUSIONS

UPA45 provided rapid relief of clinical symptoms within the first week of treatment in patients with CD.

CLINICALTRIALS

gov numbers: NCT03345849, NCT03345836, and NCT03345823.

The Future of Clinical Trials in Inflammatory Bowel Disease

The medical management of inflammatory bowel disease (IBD) has been transformed over the past few decades by the approval of multiple classes of advanced therapies and the integration of more targeted treatment strategies for Crohn's disease and ulcerative colitis. These changes have been driven by an increasing number of pivotal randomized controlled trials, which have grown in size and complexity over time. Several landmark studies that are anticipated to change current IBD management paradigms have recently been completed or are on-going, including the first head-to-head biologic trials, advanced combination treatment trials, therapeutic strategy and treatment target trials, and multiple phase 3 registrational programs of novel compounds. Despite these advances, the future of IBD trials also faces major challenges with respect to cost, feasibility, and recruitment. Accordingly, innovative methods for early and late phase randomized controlled trials must be adopted. In this review, we provide a comprehensive overview of the evolution of modern IBD trials, discuss methods for improving trial efficiency in early and late phase development, and provide insights into the interpretation and implications of these data for clinical care.

Vedolizumab, Adalimumab, and Methotrexate Combination Therapy in Crohn's Disease (EXPLORER)

BACKGROUND & AIMS

Although biologics have revolutionized the treatment of Crohn's disease (CD), an efficacy ceiling has been reached. Combining biologic therapies may improve remission rates.

METHODS

EXPLORER, a phase 4, single-arm, open-label study, evaluated triple combination therapy with vedolizumab (300 mg on day 1, weeks 2 and 6, and then every 8 weeks), adalimumab (160 mg on day 2, 80 mg at week 2, then 40 mg every 2 weeks), and methotrexate (15 mg weekly) in biologic-naïve patients with newly diagnosed, moderate- to high-risk CD. Endoscopic remission at week 26 (primary end point; Simple Endoscopic Score for CD ≤2), clinical remission at weeks 10 and 26 (secondary end point; Crohn's Disease Activity Index <150), and incidences of adverse events and serious adverse events were evaluated.

RESULTS

Among 55 enrolled patients, the mean CD duration was 0.4 years, the mean baseline Simple Endoscopic Score for CD was 12.6, and the mean baseline Crohn's Disease Activity Index was 265.5. At week 26, 19 patients (34.5%) were in endoscopic remission. At weeks 10 and 26, 34 (61.8%) and 30 patients (54.5%), respectively, were in clinical remission. Post hoc Bayesian analysis showed that the probabilities that triple combination therapy produced a higher endoscopic remission rate (33.5%; 95% credible interval, 22.4-45.7) than placebo (14%), vedolizumab monotherapy (27%), or adalimumab monotherapy (30%) were 99.9% or higher, 86.3%, and 71.4%, respectively. Six patients had serious adverse events.

CONCLUSIONS

Combination therapy resulted in endoscopic and clinical remission at week 26 in 34.5% and 54.5% of patients, respectively, with no safety signal related to the treatment regimen. This supports further evaluation of combination therapy in CD.

CLINICALTRIALS

gov number: NCT02764762.

Endoscopic and Histological Placebo Rates in Crohn's Disease Clinical Trials: A Systematic Review and Meta-analysis

BACKGROUND

Precise estimates of placebo response rates help efficient clinical trial design. In this systematic review and meta-analysis, we assessed contemporary placebo endoscopic and histological response rates in Crohn's disease (CD) clinical trials.

METHODS

MEDLINE, EMBASE, and Cochrane CENTRAL were searched from inception to April 2022 to identify placebo-controlled studies of pharmacological interventions for CD. Endoscopic response, remission, and mucosal healing rates for participants assigned to placebo in induction and maintenance studies were pooled using a random-effects model. Point estimates and associated 95% confidence intervals (CIs) were calculated.

RESULTS

In total, 16 studies (11 induction, 3 maintenance, 2 induction and maintenance) that randomized 1646 participants to placebo were eligible. For induction trials, the pooled placebo endoscopic response, endoscopic remission, and mucosal healing rates in participants assigned to placebo were 13% (95% CI, 10-16; I2 = 14.1%; P = .14), 6% (95% CI, 3-11; I2 = 74.7%; P < .001), and 6% (95% CI, 4-9; I2 = 26.9%; P = .29), respectively. The pooled endoscopic remission rate in patients who were bio-naïve was 10% (95% CI, 4-23) compared with only 4% (95% CI, 3-7) in bio-experienced patients. For maintenance trials, the pooled endoscopic response, remission, and mucosal healing rates were 7% (95% CI, 1-31; I2 = 78.2%; P = .004), 11% (95% CI, 4-27; I2 = 70.8%; P = .06), and 7% (95% CI, 3-15; I2 = 29.7; P = .23), respectively. Only 3 trials assessed histological outcomes.

CONCLUSIONS

Endoscopic placebo rates vary according to trial phase and prior biologic exposure. These contemporary data will serve to inform CD trial design, sample size calculation, and end point selection for future trials.

A Comparison of Treatment Effect Sizes in Matched Phase 2 and Phase 3 Trials of Advanced Therapeutics in Inflammatory Bowel Disease: Systematic Review and Meta-Analysis

INTRODUCTION

Phase 2 trials are fundamental to the rational and efficient design of phase 3 trials. We aimed to determine the relationship of treatment effect size estimates from phase 2 and phase 3 clinical trials on advanced therapeutics in inflammatory bowel disease.

METHODS

MEDLINE, EMBASE, CENTRAL, and the Cochrane library were searched from inception to December 19, 2022, to identify paired phase 2 and 3 placebo-controlled induction studies of advanced therapeutics for Crohn's disease (CD) and ulcerative colitis (UC). Treatment effect sizes were expressed as a risk ratio (RR) between the active arm and placebo arm. For the same therapeutics, RRs from phase 2 trials were divided by the RR from phase 3 trial to quantify the relationship of effect sizes between phases.

RESULTS

Twenty-two studies (9 phase 2 trials, 13 phase 3 trials) were included for CD and 30 studies (12 phase 2 trials, 18 phase 3 trials) for UC. In UC (pooled RR 0.72; 95% confidence interval: 0.58-0.86; RR <1 indicates smaller treatment effect sizes in phase 2 trials), but not CD (pooled RR 1.01; 95% confidence interval: 0.84-1.18), phase 2 trials systematically underestimated treatment effect sizes for the primary endpoint compared with phase 3 trials. The underestimation was observed for clinical, but not endoscopic, endpoints in UC.

DISCUSSION

Treatment effect sizes for the primary and clinical endpoints were similar across clinical trial phases in CD, but not UC, where only endoscopic endpoints were comparable. This will help inform clinical development plans and future trial design.

Predictors of Clinical Remission to Placebo in Clinical Trials of Crohn's Disease

BACKGROUND

In placebo-controlled clinical trials for Crohn's disease (CD), some placebo-treated patients demonstrate improvement. However, it is unclear what factors contribute to placebo response and remission.

METHODS

This was a post hoc analysis of 3 placebo-controlled clinical trial programs (GEMINI-2, UNITI-1/2, and CLASSIC-1) of moderate-severe CD evaluating the efficacy of vedolizumab, ustekinumab, and adalimumab. Baseline predictors of clinical remission at the end of induction (week 4/6), defined as Crohn's Disease Activity Index <150 were evaluated among placebo-treated patients. Clinical response (decrease in Crohn's Disease Activity Index ≥100 points from baseline) at the end of induction was also evaluated. Univariate analyses were performed and predictors with P < .10 were included in multivariable analyses.

RESULTS

A total of 683 patients (148 from GEMINI-2, 470 from UNITI-1/2, and 65 from CLASSIC-1) treated with placebo were included. Of the predictors evaluated, C-reactive protein <5 mg/L (odds ratio [OR], 1.66; 95% confidence interval [CI], 1.04-2.67; P = .035), albumin >40 g/L (OR, 1.57; 95% CI, 1.05-2.93; P = .023), and disease duration <5 years (OR, 1.70; 95% CI, 1.05-2.75; P = .032) were included in the multivariable model for clinical remission. Disease duration <5 years was the only variable that retained significance on multivariable analysis (adjusted OR, 1.67; 95% CI, 1.02-2.73; P = .040). For clinical response, isolated ileal disease and disease duration <1 year were included in the multivariable model, of which only the latter retained significance (adjusted OR, 1.84; 95% CI, 1.04-3.24; P = .035).

CONCLUSIONS

Strategies that reduce placebo response rates in clinical trials of CD should be considered, including stratification or exclusion of subjects by disease duration and mild disease severity as measured by objective biomarkers.

Predictors of Placebo Induction Response and Remission in Ulcerative Colitis

BACKGROUND & AIMS

High placebo response rates in clinical trials of ulcerative colitis (UC) have been reported previously. However, data from patient-level analyses are lacking. We assessed factors associated with clinical and endoscopic placebo response among placebo-treated patients in clinical trials of UC.

METHODS

We performed a post hoc analysis of pooled clinical trial data from GEMINI-1, ACT-1, ACT-2, PURSUIT, ULTRA-2, OCTAVE-1, and OCTAVE-2. Predictors were assessed in placebo-treated patients for their association with end of induction (week 6 of 8) clinical response (reduction in total Mayo score of ≥3 and ≥30% from baseline with ≥1 point decrease in rectal bleeding subscore [RBS] or absolute RBS ≤1); clinical remission (total Mayo score ≤2 and no subscore >1); endoscopic healing (Mayo endoscopic subscore ≤1); partial Mayo score of 0; patient-reported outcome 2-item remission (RBS of 0 and stool frequency ≤1), resolution of rectal bleeding, and stool frequency normalization. Predictors on univariate analyses with P < .05 were included in multivariate logistic regression models.

RESULTS

Placebo-treated patients with normal serum C-reactive protein and albumin levels were more likely to attain clinical response (71 of 437 [16.3%] vs 49 of 660 [7.4%]; adjusted odds ratio, 2.76; 95% confidence interval, 1.19-5.41; P = .018). Compared with patients with a Mayo endoscopic score of 2, patients with a Mayo endoscopic score of 3 were less likely to attain clinical response (105 of 556 [18.8%] vs 179 of 675 [25.9%]; adjusted odds ratio, 0.33; 95% confidence interval, 0.16-0.68; P = .003). Similar findings were observed for clinical remission and resolution of rectal bleeding.

CONCLUSIONS

Biomarkers such as normal serum C-reactive protein and albumin and baseline endoscopic severity were found to affect placebo response rates in clinical trials of UC. These findings have implications for clinical trial design in UC.

Placebo response rates in randomized controlled trials for perianal Crohn's disease: A systematic review and meta-analysis

BACKGROUND AND AIMS

Perianal fistulizing disease is a common complication of Crohn's disease (CD), for which new therapies are urgently needed. To assist design of clinical trials for novel therapeutics, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify placebo rates and identify factors influencing them in perianal CD.

METHODS

We searched MEDLINE, EMBASE and CENTRAL from inception to June 2021. Eligible studies were placebo-controlled trials of pharmacological interventions for perianal CD (pCD). Placebo fistula response and remission rates for induction and maintenance trials were extracted and pooled using a random-effects model. Mixed-effects meta-regression was used to evaluate the impact of patient and study-level characteristics on point estimates.

RESULTS

In 17 RCTs (13 induction, 5 maintenance) the pooled placebo fistula response and remission rate for induction trials was 25% (95% CI 17-36%) and 17% (95% CI 11-25%), respectively. For maintenance trials, the pooled placebo fistula response and remission rate was 23% (95% CI 17-32%) and 19% (95% CI 14-25%), respectively. Trials enrolling patients with less disease activity and a higher proportion with ileal predominant disease were associated with significantly higher placebo response rates. Trials originating in Europe (compared to North America), therapies requiring perianal injection and a longer timepoint to measure remission were associated with higher placebo remission rates.

CONCLUSIONS

Placebo response and remission rates in pCD trials are influenced by patient and disease-related factors, as well as the type of intervention being studied. These contemporary rates will inform trial design for novel therapeutics.

Ileal and colonic Crohn'´s disease: Ddoes location makes a difference in therapy efficacy?

Within the IBD entity of Crohn's disease, there is currently no differentiation between ileal and colonic manifestation for recruitment of patients in clinical trials, well-powered analysis of study results or therapeutic decisions in daily clinical practice. However, there is accumulating evidence from epidemiological, genetic, microbial, immunological, and clinical characteristics that clearly indicate that ileal Crohn's disease represents a distinct disease entity, which differentiates itself from colonic Crohn's disease. This is also reflected by lower efficacy of targeted therapies in isolated ileal compared to colonic Crohn's disease. The distinct site-specific mechanisms that drive heightened non-response in ileal disease need to be analysed in-depth in the future, to enable optimized therapy in the individual Crohn's disease patient.