Factors Affecting Clinical and Endoscopic Outcomes of Placebo Arm in Trials of Biologics and Small Molecule Drugs in Ulcerative Colitis: A Meta-Analysis

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.

Histological Remission Placebo Rates in Ulcerative Colitis Trials: A Systematic Review and Meta-analysis

BACKGROUND

High histologic remission rates have been reported with placebos in randomized controlled trials (RCTs) evaluating ulcerative colitis (UC) therapies and have varied based on trial designs. We performed a systematic review and meta-analysis to quantify placebo histological remission rates and identify factors influencing those rates.

METHODS

MEDLINE, EMBASE, and the Cochrane library were searched from inception of the databases until December 2021. We included placebo-controlled RCTs of adult patients with UC treated with aminosalicylates, corticosteroids, immunosuppressives, biologics, and small molecules. We pooled estimates using a random-effects model and performed subgroup analysis and meta-regression to evaluate the effect of different covariates on placebo rates.

RESULTS

Thirty-three studies (30 induction and 3 maintenance) were included. The overall placebo histological remission rate was 15.7% (95% confidence interval, 12.9%-19%) across all 33 studies. High heterogeneity was observed among studies with I2 = 62.10%. The pooled estimate of histological remission was 15.8% in induction studies and 14.5% in maintenance studies. Subgroup analysis revealed statistically significant differences in placebo rates when accounting for background medications, the intervention drug class, and disease severity (P = .041, .025, and .025, respectively). There was no statistical difference between induction vs maintenance studies or between different histological scales (P = .771, and .075, respectively).

CONCLUSIONS

Placebo histological remission rates range from 13% to 19% in UC RCTs, but studies are highly heterogeneous. Factors found to influence placebo rates include presence of background medications, the drug used, and the disease severity. These observations inform future trial designs to minimize placebo rates and reduce heterogeneity.

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.

Real-world evidence of tofacinitib in ulcerative colitis: short and long-term effectiveness and safety

AIMS

To assess the durability, short and long-term effectiveness and safety of tofacitinib in ulcerative colitis (UC) in clinical practice.

METHODS

Retrospective, multicentre study including UC patients who had received the first tofacitinib dose at least 8 weeks before the inclusion. Clinical effectiveness was based on Partial Mayo Score (PMS).

RESULTS

A total of 408 patients were included. Of them, 184 (45%) withdrew tofacitinib during follow-up (mean=18 months). The probability of maintaining tofacitinib was 67% at 6 m, 58% at 12 m, and 49% at 24 m. Main reason for tofacitinib withdrawal was primary non-response (44%). Older age at the start of tofacitinib and higher severity of clinical activity were associated with tofacitinib withdrawal. The proportion of patients in remission was 38% at week 4, 45% at week 8, and 47% at week 16. Having moderate-severe vs. mild disease activity at baseline and older age at tofacitinib start were associated with lower and higher likelihood of remission at week 8, respectively. Of 171 patients in remission at week 8, 83 (49%) relapsed. The probability of maintaining response was 66% at 6 m and 54% at 12 m. There were 93 adverse events related to tofacitinib treatment [including 2 pulmonary thromboembolisms (in patients with risk factors) and 2 peripheral vascular thrombosis], and 29 led to tofacitinib discontinuation.

CONCLUSIONS

Tofacitinib is effective both in the short and in the long-term in patients with UC. The safety profile is similar to that previously reported.

Effectiveness and safety of tofacitinib for the treatment of ulcerative colitis: A single-arm meta-analysis of observational studies

BACKGROUND

Several observational studies on Tofacitinib (TOFA) in ulcerative colitis (UC) have been published over the last 2 years.

AIMS

To estimate effectiveness and safety of TOFA arising from real-world experience.

METHODS

PubMed Central/Medline and Embase were systematically searched for real-world observational studies on TOFA for the treatment of UC through November 2020.

RESULTS

Seven studies comprising 759 patients met the inclusion criteria. The pooled estimate rates were 49% for clinical response, 40% for clinical remission, and 34% for corticosteroid-free clinical remission at induction, while the rates of endoscopic response and endoscopic remission were 37% and 19%, respectively. At maintenance, the pooled estimate rates of clinical response, clinical remission, and corticosteroid-free clinical remission were 36%, 35%, and 24%, respectively. The pooled estimate of incidence rate of adverse events was 53.0 per 100 person-years (PY), while the pooled estimate of incidence rate of withdrawal of TOFA due to adverse events was 9.3 per 100 PY, with a pooled rate of infections of 17.6 per 100 PY.

CONCLUSIONS

Cumulative analysis of data from real-world studies confirmed the good efficacy of TOFA in UC shown by randomized controlled trials for both induction and maintenance, while the safety profile was consistent with previous reports.

Clinical, Endoscopic and Histological Outcomes in Induction of Moderate-to-Severe Ulcerative Colitis: A Systematic Review with Meta-Analysis

BACKGROUND AND AIMS

Interest in histology for ulcerative colitis [UC] has increased recently. This systematic review and meta-analysis aims to assess, for the first time, whether histological outcomes are more informative than endoscopic and clinical outcomes in distinguishing the impact of intervention over placebo in induction trials.

METHODS

MEDLINE, ScienceDirect and Cochrane Central Register of Controlled Trials were searched to identify randomized placebo-controlled trials [RCTs] enrolling moderate-to-severe UC patients. Studies were assessed using the Quality Assessment Tool for Studies with Diverse Designs. We analysed the pooled proportion of patients achieving clinical, endoscopic and histological remission and response after a pharmacological intervention and compared the results with those of placebo-treated patients by using a random-effects model.

RESULTS

From 889 identified records, 13 RCTs were included. The odds ratio [OR] for remission was higher in patients receiving intervention than in those under placebo for clinical (OR 2.13, 95% confidence interval [CI] 1.33-3.43), endoscopic [OR 1.46, 95% CI 0.19-11.18] and histological remission [OR 1.85, 95% CI 1.20-2.84]. Significant differences were observed for all response outcomes [clinical: OR 2.27, 95% CI 1.84-2.85; endoscopic: OR 2.16, 95% CI 1.51-3.10; histological: OR 3.63, 95% CI, 1.41-9.36]. No significant heterogeneity existed; no subgroup effects were found for duration of the induction or histological scale [p > 0.05]. Clinical and histological remission and endoscopic response were concordant in discriminating interventions from placebo.

CONCLUSION

Histological outcomes are informative in trials of moderate-to-severe UC. Further studies analysing histology at the end of induction are needed to confirm its relevance in distinguishing the efficacy of an intervention over placebo in comparison to clinical and endoscopic outcomes and to explore its prognostic value.

The Placebo and Nocebo Responses in Clinical Trials in Inflammatory Bowel Diseases

Placebo and nocebo responses are mostly discussed in clinical trials with functional bowel disorders. Much less has been investigated and is known in gastrointestinal diseases beyond irritable bowel syndrome (IBS), especially in inflammatory bowel diseases (IBD). For the purpose of this review, we screened the Journal of Interdisciplinary Placebo Studies (JIPS) database with approximately 4,500 genuine placebo research articles and identified nine meta-analyses covering more than 135 randomized and placebo-controlled trials (RCTs) with more than 10,000 patients with Crohn´s disease (CD) and another five meta-analyses with 150 RCTs and more than 10,000 patients with ulcerative colitis (UC). Only three discussed nocebo effects, especially in the context of clinical use of biosimilars to treat inflammation. The articles were critically analyzed with respect to the size of the placebo response in CD and UC, its effects on clinical improvement versus maintenance of remission, and mediators and moderators of the response identified. Finally, we discussed and compared the differences and similarities of the placebo responses in IBD and IBS and the nocebo effect in switching from biologics to biosimilars in IBD management.

Efficacy of infliximab, cyclosporine and tacrolimus on ulcerative colitis: A meta-analysis

BACKGROUND

Positioning infliximab (IFX), cyclosporine and tacrolimus (TAC) for treating ulcerative colitis (UC) is in great debate.

METHODS

A literature search identified studies that investigated IFX vs. cyclosporine or IFX vs TAC in UC patients. Short-term remission, short-term, 1-year and 3-year colectomy rate were employed as primary end-points to assess efficacy. Odds ratios (ORs) with 95% confidence intervals (CIs) were analyzed.

RESULTS

Overall, 15 studies comprised 596 patients in IFX group and 866 in calcineurin inhibitors group (644 received cyclosporine and 222 received TAC). No significant difference was seen between IFX and calcineurin inhibitors with regard to short-term remission. IFX led to a lower short-term (OR: 0.59, 95% CI: 0.43-0.82, P:.001), 1-year (OR: 0.53, 95% CI: 0.38-0.73, P < .001), 3-year colectomy (OR: 0.41, 95% CI: 0.20-0.84, P:.02) than calcineurin inhibitors. IFX led to a lower short-term (OR: 0.51, 95% CI: 0.36-0.71, P < .001), 1-year (OR: 0.53, 95% CI: 0.37-0.74, P:.003) colectomy and a trend of lower 3-year colectomy (OR: 0.49, 95% CI: 0.22-1.06, P:.07) than cyclosporine while no significant difference was seen between IFX and TAC. Results of network meta-analysis showed that the order was cyclosporine, TAC and IFX from high rate to low with regard to short-term and 1-year colectomy.

CONCLUSION

IFX treatment leads to a lower short-term, 1-year colectomy rate and a trend of lower 3-year colectomy rate in UC patients than cyclosporine while no significant difference is seen between IFX and TAC. TAC may be superior than cyclosporine with regard to efficacy based on indirect comparisons. Randomized trials with fixed protocol are warranted to identify the optimal medical strategy in patients with UC.

JAK Inhibition as a Therapeutic Strategy for Inflammatory Bowel Disease

Background:

Inflammatory bowel disease, including both Crohn’s disease and ulcerative colitis, are two chronic and progressive disorders affecting the gastrointestinal tract. Research on the molecular mechanisms of both diseases has led to the introduction of targeted therapies which are able to selectively block the key inflammatory mediators.

Methods:

Here, we discuss the current evidence about the mechanism of action with an up to date review of the efficacy and safety of Janus kinase inhibitors in inflammatory bowel disease.

Results:

Multiple small molecule drugs have been evaluated for their use in both ulcerative colitis and Crohn’s disease. Janus kinase inhibitors represent the most important family of these drugs, as their particular mechanism of action enables a simultaneous and effective blockade of multiple cytokines involved in the pathogenesis of the disease.

Conclusion:

Janus kinase inhibitors represent a promising therapeutic strategy, especially in ulcerative colitis. More data are still necessary regarding its efficacy and safety in clinical practice.

Exploratory clinical characterization of experimentally-induced ulcerative colitis nonhuman primates

A limitation of currently used preclinical models of colitis is that disease and treatment assessment methods differ from clinically used methods. Thus, a modified Mayo score and an endoscopic index (EI) were developed for use in cynomolgus macaques with 0.25% dextran sulfate sodium (DSS)-induced ulcerative colitis. Macaques were treated with water with DSS for two weeks followed by water without DSS for two weeks. Disease activity was classified according to a modified Mayo score: stool consistency, rectal bleeding, colonoscopy examination and global assessment. Findings on colonoscopy were further graded according the Rachmilewitz EI. To demonstrate the sensitivity of the modified Mayo score and EI to therapeutic intervention, macaques were treated with the anti-inflammatory steroid prednisolone followed eight weeks later by the integrin antibody vedolizumab. Before DSS treatment, normal stool consistency and no rectal bleeding were observed. Colonoscopy demonstrated no mucosal abnormalities. Following the first DSS treatment, Mayo score and EI indicated signs of mild colitis. Following subsequent DSS treatments, mild to moderate colitis emerged with each DSS treatment and reduced signs of colitis were observed 2 weeks after DSS treatment termination. Prednisolone treatment during DSS treatment suppressed the emergence of colitis. Vedolizumab reduced signs of colitis during DSS treatment and further reduced signs of colitis that persisted after termination of DSS treatment. The current study demonstrated the potential of utilizing clinical outcome measures to assess experimentally-induced colitis in the macaque. Furthermore, signs of colitis, as assessed with the current methods, were reduced following therapeutic treatment. The current findings suggest that clinically relevant outcome measures in the macaque model of ulcerative colitis could be used to test novel treatments.

Placebo Responses and Placebo Effects in Functional Gastrointestinal Disorders

Much has been written about the placebo effects in functional gastrointestinal disorders (FGD), especially in irritable bowel syndrome (IBS), driven by the early hypothesis that in randomized controlled trials (RCTs) of IBS, the placebo effect might be specifically high and thus, corrupts the efficacy of novel drugs developed for this condition. This narrative review is based on a specific search method, a database (www.jips.online) developed since 2004 containing more than 4,500 papers (data papers, meta-analyses, systematic reviews, reviews) pertinent to the topic placebo effects/placebo response. Three central questions-deducted from the body of current literature-are addressed to explore the evidence behind this hypothesis: What is the size placebo effect in FGD, especially in IBS, and is it different from the placebo effect seen in other gastrointestinal disorders? Is the placebo effect in FGD different from other functional, non-intestinal disorders, e.g. in other pain syndromes? Is the placebo effect in FGD related to placebo effects seen in psychiatry, e.g. in depression, anxiety disorders, and alike? Following this discussion, a fourth question is raised as the result of the three: What are the consequences of this for future drug trials in FGD? In summary it is concluded that, contrary to common belief and discussion, the placebo effect seen in RCT in FGD is not specifically high and extraordinary as compared to other comparable (i.e. functional) disorders. It shares less than expected commonalities with the placebo effect in psychiatry, and very few predictors have yet been identified that determine its effect size, especially some that are driven by design features of the studies. Current practice of RCT in IBS seems to limit and control the placebo effect quite well, and future trial practice, e.g. head-to-head trial, still offers options to maintain this control, even in the absence of placebos used.

Placebos and the Placebo Effect in Drug Trials

In this review, we explored different ways of controlling the placebo effects in clinical trials and described various factors that may increase/decrease the placebo effect in randomized placebo-controlled trials. These factors can be subdivided into four groups, and while not all factors are effective in every study and under all clinical conditions, they show on the whole that - even under the ideal condition of drug therapy, where blinded placebo provision is much easier and warranted than in, e.g., psychotherapy - many factors need to be controlled to ascertain that the goal of the clinical trials, fair assessment of superiority of the drug over placebo in placebo-controlled trials and fair assessment of non-inferiority of the drug compared to another drug in comparator trials, is reached. Ignorance towards the placebo effect, which was common in the past, is no longer acceptable; instead, it should be the goal of all therapeutic trials to minimize the placebo effect in clinical trials, while utilizing and maximizing it in clinical routine.