Placebo Response Rates Research Articles

Medical Therapies for Prevention and Treatment of Inflammatory Pouch Disorders - A Systematic Review and Meta-analysis.

Pouchitis and Crohn's like disease of the pouch (CLDP) are common in patients who undergo ileal pouch anal anastomosis for ulcerative colitis (UC). We conducted separate systematic reviews to evaluate the effectiveness of available interventions to prevent and treat pouchitis and CLDP. Through systematic literature reviews, we identified studies that evaluated the effectiveness of probiotics, antibiotics, 5-aminosalicylates, non-systemic oral corticosteroids, and advanced therapies for prevention and treatment of pouchitis and CLDP for meta-analysis. Primary outcomes were occurrence of pouchitis for pouchitis prevention and clinical response for pouchitis and CDLP treatment. We estimated the relative effectiveness of these interventions using the existing placebo response rates or hypothetical spontaneous improvement rates derived from clinical trials of pouchitis, UC and Crohn's disease. Probiotics were effective for primary (RR 0.18; 95% CI 0.05-0.62) and secondary prevention (RR 0.17; 95% CI 0.09-0.34) of pouchitis. Antibiotics were effective for treatment of acute and chronic pouchitis (12 cohorts; RR 1.67; 95% CI 1.34-2.01; response rate 65%; 95% CI 52-75) with ciprofloxacin and metronidazole-based regimens being more effective than rifaximin. Advanced therapies were effective for treatment of chronic antibiotic-refractory pouchitis (31 cohorts; RR 1.71; 95% CI 1.28-2.56; response rate 50%; 95% CI 43-57) and CLDP (10 cohorts; RR 2.49; 95% CI 1.87-3.73; response rate 74%; 95% CI 68-79) without significant difference between classes. Multiple medical interventions are effective for prevention and treatment of pouchitis and CLDP. Given the overall low quality of data, further research is needed to confirm these findings.

Placebo rates in Crohn’s disease randomized clinical trials: An individual patient data meta-analysis

Understanding placebo rates is critical for efficient clinical trial design. We assessed placebo rates and associated factors using individual patient data (IPD) from Crohn's disease (CD) trials. We conducted a meta-analysis of phase 2/3 placebo-controlled trials evaluating advanced therapies in moderate-to-severe CD (2010-2021). Deidentified IPD were obtained through Vivli Inc. and Yale University Open Data Access Project. Primary outcomes were clinical response and remission. Pooled placebo rates and 95% confidence intervals (CIs) were estimated using one- and two-stage meta-analytical approaches. Regression analyses identified patient-level factors associated with placebo rates. Using IPD from eight induction (n=1147) and four maintenance (n=524) trials, overall placebo clinical response and remission rates for induction were 27% (95%CI=23-32%) and 10% (95%CI=8-14%) respectively, and 32% (95%CI=23-42%) and 22% (95%CI=14-33%) for maintenance, respectively. Among bio-naïve patients, placebo response and remission rates during induction were 29% (95%CI=24-35%) and 11% (95%CI=8-15%) respectively, and 26% (95% CI=20-33%) and 10% (95% CI=8-14%) for bio-exposed, respectively. During maintenance, bio-naïve response and remission rates were 41% (95%CI=34-48%) and 32% (95%CI=24-40%), respectively, and 29% (95%CI=24-34%) and 16% (95%CI=13-21%) for bio-exposed, respectively. Higher baseline C-reactive protein concentration predicted lower placebo rates, while higher baseline albumin levels and body mass index increased the odds of placebo outcomes. Increased baseline Crohn's Disease Activity Index and 2-item patient-reported outcome scores predicted higher response rates in induction, lower response rates in maintenance, and lower remission rates in induction and maintenance. Patient- and trial-level characteristics influence placebo rates in CD trials. Careful implementation of eligibility criteria, outcome definitions, and patient stratification may reduce placebo rates.

Triptans in the Acute Migraine Management of Children and Adolescents: An Update.

To summarize recent findings regarding triptan use in the acute treatment of pediatric migraine. Prevalence of pediatric migraine is rising. The American Headache Society and American Academy of Neurology updated guidelines to provide evidence-based recommendations for the treatment of acute migraine in youth. In the setting of a dearth of new randomized controlled trials (RCTs), we review current guidelines, triptan use in the emergency department, and an era of secondary analyses. Measuring the efficacy of triptans in pediatric migraine has been challenged by high placebo response rates. Secondary analyses, combining data from multiple RCTs, support that triptans are safe and effective in the treatment of migraine. Triptans are a vital tool and the only FDA-approved migraine-specific treatment available in pediatrics. There is a need for further studies and funding support in pediatric headache medicine.

Placebo Effects Are Small on Average in the 7.5% CO2 Inhalational Model of Generalized Anxiety.

Anxiety disorders are highly prevalent and socio-economically costly. Novel pharmacological treatments for these disorders are needed because many patients do not respond to current agents or experience unwanted side effects. However, a barrier to treatment development is the variable and large placebo response rate seen in trials of novel anxiolytics. Despite this, the mechanisms that drive placebo responses in anxiety disorders have been little investigated, possibly due to low availability of convenient experimental paradigms. We aimed to develop and test a novel protocol for inducing placebo anxiolysis in the 7.5% CO2 inhalational model of generalized anxiety in healthy volunteers. Following a baseline 20-minute CO2 challenge, 32 healthy volunteers were administered a placebo intranasal spray labelled as either the anxiolytic "lorazepam" or "saline." Following this, participants surreptitiously underwent a 20-minute inhalation of normal air. Post-conditioning, a second dose of the placebo was administered, after which participants completed another CO2 challenge. Participants administered sham "lorazepam" reported significant positive expectations of reduced anxiety (P = .001), but there was no group-level placebo effect on anxiety following CO2 challenge post-conditioning (Ps > .350). Surprisingly, we found many participants exhibited unexpected worsening of anxiety, despite positive expectations. Contrary to our hypothesis, our novel paradigm did not induce a placebo response, on average. It is possible that effects of 7.5% CO2 inhalation on prefrontal cortex function or behavior in line with a Bayesian predictive coding framework attenuated the effect of expectations on subsequent placebo response. Future studies are needed to explore these possibilities.

Placebo response to sham electroacupuncture in patients with chronic functional constipation: A secondary analysis.

Chronic severe functional constipation is a common disease that requires novel and effective treatment strategies. Acupuncture might constitute a promising therapeutic approach for chronic constipation, but it reportedly engenders an enhanced placebo response. Herein, we aimed to determine the magnitude of the placebo responses to electroacupuncture for constipation and identify its influencing factors. In this secondary analysis of a multicenter randomized trial, patients were randomized to a sham electroacupuncture group, which was administered for 8 weeks in 24 sessions of superficial needling at nonacupoints. The placebo response rates were assessed using three responder criteria: ≥3 complete spontaneous bowel movements per week (CSBMs/week), overall CSBM, and sustained CSBM. Logistic regression with backward selection method was employed to identify the potential factors that affected the placebo response. Overall, 539 patients were included in the study. The placebo response rate was 10.58%, 9.46%, and 9.09% according to the three aforementioned criteria, respectively. Those who exhibited more CSBMs/week at baseline were more likely to respond to sham electroacupuncture. Among patients with more than one CSBM per week at baseline, the response rates for achieving the criteria of ≥3 CSBMs per week, overall CSBM, and sustained CSBM were 25.40%, 30.16%, and 22.22%. Electroacupuncture did not demonstrate a large placebo response in functional constipation treatment. The number of CSBMs at baseline may be a moderator of the placebo response to sham electroacupuncture. Thus, superficial needling sham acupuncture may be considered an ideal sham control for clinical trials of chronic constipation.

P1013 Placebo rates in Crohn's disease: An individual patient data meta-analysis from multiple randomised controlled trials

Abstract Background Estimating placebo rates and their determinants is essential for designing efficient randomised clinical trials (RCTs) in inflammatory bowel disease. We conducted an individual patient data (IPD) meta-analysis of placebo data from RCTs in Crohn’s disease (CD). Methods MEDLINE, Embase, and CENTRAL were searched from 01/2010 to 01/2020 for contemporary phase 2 and 3 placebo-controlled RCTs of biologics in moderate-to-severe CD. De-identified IPD from eligible trials that were available through the Vivli and Yale University Open Data Access data-sharing platforms were obtained. Primary outcomes were placebo clinical response and remission. Pooled placebo rates and 95% CIs were estimated using a 2-stage meta-analytical approach. Significant patient-level factors (P<0.05) associated with placebo rates were identified using regression analyses. Results Placebo IPD were available from 8 induction (n=1147) and 4 maintenance trials (n=524). Pooled placebo clinical response and remission rates varied based on outcome definition and prior biologic exposure (Figure). In induction trials, overall placebo response and remission rates were 27% (95% CI 23-32%) and 10% (95% CI 8-14%), respectively. Among bio-exposed patients, placebo response and remission rates were 27% (95% CI 16-40%) and 9% (95% CI 6-15%), respectively, compared with 29% (95% CI 24-34%) and 11% (95% CI 8-15%) for bio-naïve patients. Overall placebo response and remission rates in maintenance trials were 32% (95% CI 23%-42%) and 22% (95% CI 14-33%), respectively. Corresponding placebo response and remission rates for bio-exposed patients were 21% (95% CI 8-46%) and 17% (95% CI 11-25%), and 36% (95% CI 28-44%) and 24% (95% CI 15-36%) for bio-naïve patients. Placebo rates were lowest when response was defined as a ≥100-point decrease from baseline in the Crohn's Disease Activity Index (CDAI) score, and when remission was defined using stool frequency (≤1.5) and abdominal pain (≤1) subscores. Higher baseline C-reactive protein concentrations were associated with lower odds of placebo response and remission, while higher baseline albumin levels increased the odds of these outcomes (Table). Increased baseline CDAI and 2-item patient-reported outcome (PRO2) scores predicted higher odds of placebo response in induction trials, yet this reduced the odds of remission in induction trials and of both outcomes in maintenance trials. Prior failure to tumour necrosis factor (TNF) antagonist therapy was more predictive than prior TNF antagonist/biologic exposure for reducing the odds of placebo response and remission. Conclusion Placebo rates and the patient-level factors influencing them vary according to study design, clinical outcome measure and outcome definitions.

OP18 Efficacy and safety of darvadstrocel treatment in patients with complex perianal fistulas and Crohn’s Disease: results from the global ADMIRE-CD II phase 3 study

Abstract Background Complex perianal fistulas are a serious complication in patients with Crohn’s disease (CD). Darvadstrocel (DVS), a suspension of expanded adult allogeneic adipose-derived mesenchymal stem cells, is approved in Europe and Japan for treatment of complex Crohn’s perianal fistulas (CPF). The global ADMIRE-CD II phase 3 randomized double-blind placebo-controlled study evaluated the efficacy and safety of DVS for treatment of complex CPF. Methods Patients aged 18–75 years with clinically controlled, inactive or mildly active CD and complex CPF (≤2 internal openings [IO] and ≤3 external openings [EOs]) who had an inadequate, or a loss of response to immunosuppressive agents or biologics were included. Patients were randomized 1:1 to receive a local injection of DVS as a single dose (120 x 106 cells/24 mL) or placebo. In all patients, fistula preconditioning included vigorous curettage and seton placement 2–3 weeks before treatment, and seton removal, a further curettage and closure of IOs immediately before treatment. The primary endpoint was combined remission (closure of all treated EOs that were draining at baseline, despite gentle finger compression, and absence of collections >2 cm confirmed by MRI) at 24 weeks. Secondary endpoints included combined remission at 52 weeks, clinical remission (closure of all treated EOs without MRI confirmation) at 24 and 52 weeks, and time to clinical remission at 24 weeks. Safety was monitored up to 52 weeks. Results From 19 Oct 2017 to 26 Jul 2023, 568 patients received DVS (n = 283) or placebo (n = 285) with fistula preconditioning; 56.3% of patients enrolled in Europe and Israel, and 43.7% in North America. Mean (SD) age, sex and race were similar in the DVS and placebo arms (38.4 [11.9] vs 37.7 [10.8] years; 42.8% vs 45.6% female; 85.9% vs 89.1% White). Combined remission rates at 24 weeks did not statistically differ between treatments (48.8% DVS vs 46.3% placebo) and there were no differences in secondary endpoints (Table 1; Figure 1). Based on health authority guidelines, post hoc analyses of patients randomized before COVID-19 (11 March 2020; n = 141 DVS, n = 143 placebo) were performed: combined remission rates at 24 weeks were 46.8% (DVS) and 38.5% (placebo). The safety profile for DVS was consistent with prior studies with no new safety signals (Table 1). Conclusion The efficacy outcomes assessed did not statistically differ between DVS and placebo, and the placebo response rate (with fistula preconditioning) was higher than expected. Post hoc analyses revealed lower placebo response rates in patients randomized before COVID-19 (similar to the pivotal ADMIRE CD I study) than the overall placebo arm. DVS was well tolerated.

Irritable bowel syndrome in children: the placebo response rate and influencing factors a meta-analysis.

Irritable bowel syndrome is common in children and exhibits a high placebo response. This study was to explore the placebo response rate and its influencing factors in children with irritable bowel syndrome. A systematic search was performed on Pubmed, Embase, MEDLINE, Cochrane Library, CNKI, Wanfang, and CBM from database inception to March 2022. Randomized controlled trials of irritable bowel syndrome in children were included in the study. The primary outcome was the placebo response rate of improvement. Thirteen studies were included, with 445 patients in the placebo group. The rate of improvement and abdominal pain disappearance were 28.2% (95% CI, 16.6-39.9%) and 5% (95% CI, 0-18.4%). The placebo response based on the abdominal pain score was 0.675 (95% CI, 0.203-1.147). The mode of administration (P < 0.01), dosing schedule (P < 0.01), and clinical outcome assessor (P = 0.04) have a significant impact on the magnitude of placebo effect. The placebo response rate for pediatric irritable bowel syndrome was 28.2%. In clinical trials, reducing dosing frequency, selecting appropriate dosage forms, and using patient-reported outcomes can help mitigate the placebo effect. This is the first meta-analysis to assess the placebo response rates for improvement and disappearance in children with IBS. The finding suggested that the mode of administration, dosing schedule, and clinical outcome assessor could potentially influence the magnitude of the placebo effect in children with IBS. This study would provide a basis for estimating sample size in clinical trial design with a placebo control.

Results of a randomized, double-blind, placebo-controlled trial of lorcaserin in cocaine use disorder

BackgroundCocaine use disorder (CUD) is a major public health problem for which there is no approved pharmacotherapy. The primary purpose of this study was to evaluate the ability of lorcaserin, a 5-hydroxytryptamine2 C (5-HT2 C) receptor agonist, to facilitate abstinence in individuals seeking treatment for CUD. MethodsThis was a 12-site, randomized, parallel arm study with a 13-week Treatment Phase that included a 1-week, single-blind run-in period when all participants received twice daily 15mg acetazolamide capsules (a medication adherence marker), followed by randomization to either twice daily 10mg lorcaserin or placebo capsules for the remaining 12 weeks. Pre-randomization data were utilized in an enrichment strategy aimed at achieving high levels of medication adherence and low placebo response rates in a subgroup of participants that qualified for the “efficacy population.” For lorcaserin vs. placebo, the primary efficacy endpoint was the proportion of participants in the efficacy population achieving abstinence during the last three weeks of treatment, as evidenced by self-report of no cocaine use, confirmed by urine testing. Results: Within the efficacy population, 1.1% of 91 participants receiving lorcaserin and 4.3% of 92 receiving placebo achieved abstinence during the last 3 weeks of treatment. Among all randomized participants, 2.5% of 118 receiving lorcaserin and 5.6% of 124 receiving placebo achieved similar abstinence. Study participants receiving lorcaserin exhibited significantly greater reductions in body weight and BMI, indicating that medication adherence was sufficient to produce a pharmacological effect. Conclusions: Twice daily 10mg lorcaserin failed to demonstrate efficacy in the treatment of CUD.

Addressing high placebo response rates in randomized clinical trials for hidradenitis suppurativa.

Addressing high placebo response rates in randomized clinical trials for hidradenitis suppurativa.

Potential strategies to optimize the efficacy of antidepressants: Beyond the monoamine theory

Depression is characterized by a feeling of sadness and a lack of pleasure, with impaired daily functioning and poor quality of life. The neurobiology and the pathogenesis of depression are not fully understood yet. Several hypotheses have been discussed including, monoamine theory, neurotransmission, oxidation, inflammation, glutamatergic transmission, neurotrophic factors, and others. Reviewing three decades of randomized controlled trials of antidepressants revealed that the antidepressants response rate is about 54% compared to a placebo response rate of 37%. Treatment-resistant depression (TRD) could be defined as an inadequate response to two different of antidepressants. In TRD, a combination strategy of using two FDA-approved antidepressants is used, which may predispose patients to adverse effects. Therefore, there is a compelling need to explore the potential “out of the box” adjuvants to antidepressants to provide higher and consistent response rates with high tolerability. These adjuvants could be medications available for other indications, food supplements, or even experimental drugs. This review will highlight potentially beneficial adjuvants to antidepressants such as nitric oxide modulators, NMDA antagonists, anti-inflammatory, antioxidants, mitochondrial modulators, insulin sensitizers, opioids, probiotics, and GABA agonists.

An independent audit of electroconvulsive therapy patient information leaflets in Northern Ireland, Scotland and Wales.

To evaluate the accuracy of patient information leaflets about electroconvulsive therapy (ECT) used in Northern Ireland, Scotland and Wales, and their compliance with the principle of informed consent. To replicate an audit in England, Freedom of Information Act requests were sent to the 26 providers of ECT for their ECT patient information leaflet. These were scored, by two independent raters, on the same 40-item accuracy measure used in the England audit. The number of accurate statements (out of a possible 29) ranged from seven to 20, with a mean of 16.9. The most frequently omitted statements included: cardiovascular risks (mentioned by five leaflets), that it is not known how ECT works (3), risk of mortality (2), risks from multiple general anaesthetic procedures (2), how to access a legal advocate (2) and that that there is no evidence of long-term benefits (1). The leaflets made between six and nine inaccurate statements (out of 11) with a mean of 7.0. Nineteen minimised memory loss, blamed the memory loss on depression, claimed that ECT is the 'most effective treatment' and asserted it has very high response rates without mentioning similar placebo response rates. All 23 leaflets wrongly told patients that ECT saves lives. Electroconvulsive therapy information leaflets in these three nations are barely more accurate than those in England and do not comply with the ethical principle of informed consent. Patients and families across the UK are systematically being misled about the risks they are taking and the limited nature of ECT's benefits.

A randomised, double-blind, placebo-controlled study of the LAG-3-depleting monoclonal antibody GSK2831781 in patients with active ulcerative colitis.

Selective depletion of T cells expressing LAG-3, an immune checkpoint receptor that is upregulated on activated T cells, has been investigated in pre-clinical models as a potential therapeutic approach in inflammatory and autoimmune diseases where activated T cells are implicated. GSK2831781, a depleting monoclonal antibody that specifically binds LAG-3 proteins, may deplete activated LAG-3+ cells in ulcerative colitis (UC). Patients with moderate to severe UC were randomised to GSK2831781 or placebo. Safety, tolerability, efficacy, pharmacokinetics and pharmacodynamics of GSK2831781 were evaluated. One hundred four participants across all dose levels were randomised prior to an interim analysis indicating efficacy futility criteria had been met. Efficacy results focus on the double-blind induction phase of the study (GSK2831781 450 mg intravenously [IV], N = 48; placebo, N = 27). Median change from baseline (95% credible interval [CrI]) in complete Mayo score was similar between groups (GSK2831781 450 mg IV: -1.4 [-2.2, -0.7]; placebo: -1.4 [-2.4, -0.5]). Response rates for endoscopic improvement favoured placebo. Clinical remission rates were similar between groups. In the 450-mg IV group, 14 (29%) participants had an adverse event of UC versus 1 (4%) with placebo. LAG-3+ cells were depleted to 51% of baseline in blood; however, there was no reduction in LAG-3+ cells in the colonic mucosa. Transcriptomic analysis of colon biopsies showed no difference between groups. Despite evidence of target cell depletion in blood, GSK2831781 failed to reduce inflammation in the colonic mucosa suggesting no pharmacological effect. The study was terminated early (NCT03893565).

A comparative evaluation of placebo effect on pain perception parameters in open-label versus double-blind groups: a prospective randomized pilot study in healthy volunteers

Background: Considerable placebo response rate is commonly observed in placebo-controlled trials involving analgesics. However, there is paucity of evidence with regard to comparison of effect of open-label placebo versus double-blind placebo on pain perception. Methods: In this study, cold water maintained at 4±1°C was used to induce experimental pain. Enrolled subjects were randomized to receive either 2% lignocaine gel as active drug or K-Y jelly as placebo as per the groups in open-label (two groups) and double-blind (two groups) study. Pain perception was evaluated using pain threshold time and pain tolerance time after immersion of subject’s hand in the cold water. Pain intensity was assessed using visual analogue scale (VAS). Results: Sixty-nine subjects were randomized into 4 study groups namely open-label lignocaine (OLL; N=17), open-label placebo (OLP; N=18), double-blind lignocaine (DBL; N=17) and double-blind placebo (DBP; N=17). OLP application increased pain intensity on VAS from 67 (47, 84) to 72 (39, 88) mm (p=0.018). OLL application reduced pain perception pain threshold time from 20.4 (4.0, 45.1) to 24.1 (6.3, 124.2) seconds (p=0.049) and pain tolerance time from 32.7 (6.8, 110.2) to 40.0 (7.7, 156.7) seconds (p=0.019). The change in pain parameters (before and after application of study intervention) was comparable without any significant difference among the four study groups (p=0.257 for pain threshold time, p=0.165 for pain tolerance time and p=0.563 for pain intensity score). Conclusions: Lignocaine and placebo gel application showed comparable change in pain perception irrespective of blinding.

1134 Comparison of placebo response rates in failed vs successful phase 2/3 clinical trials in hidradenitis suppurativa and atopic dermatitis

1134 Comparison of placebo response rates in failed vs successful phase 2/3 clinical trials in hidradenitis suppurativa and atopic dermatitis

Predictors of placebo response in three large clinical trials of the V1a receptor antagonist balovaptan in autism spectrum disorder

High rates of placebo response are increasingly implicated in failed autism spectrum disorder (ASD) clinical trials. Despite this, there are limited investigations of placebo response in ASD. We sought to identify baseline predictors of placebo response and quantify their influence on clinical scales of interest for three harmonized randomized clinical trials of balovaptan, a V1a receptor antagonist. We employed a two-step approach to identify predictors of placebo response on the Vineland-II two-domain composite (2DC) (primary outcome and a caregiver measure) and Clinical Global Impression (CGI) scale (secondary outcome and a clinician measure). The initial candidate predictor set of variables pertained to participant-level, site-specific, and protocol-related factors. Step 1 aimed to identify influential predictors of placebo response using Least Absolute Shrinkage and Selection Operator (LASSO) regression, while Step 2 quantified the influence of predictors via linear regression. Results were validated through statistical bootstrapping approaches with 500 replications of the analysis dataset. The pooled participant-level dataset included individuals with ASD aged 5 to 62 years (mean age 21 [SD 10]), among which 263 and 172 participants received placebo at Weeks 12 and 24, respectively. Although no influential predictors were identified for CGI, findings for Vineland-II 2DC are robust and informative. Decreased placebo response was predicted by higher baseline Vineland-II 2DC (i.e., more advanced adaptive function), longer trial duration, and European (vs United States) sites, while increased placebo response was predicted by commercial (vs academic) sites, attention deficit hyperactivity disorder and depression. Identification of these factors may be useful in anticipating and mitigating placebo response in drug development efforts in ASD and across developmental and psychiatric conditions.

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

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. 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. 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. 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.

Efficacy and Safety of Vibegron for the Treatment of Overactive Bladder in Women: A Subgroup Analysis From the Double-Blind, Randomized, Controlled EMPOWUR Trial

ABSTRACT The sudden, intense urge to urinate, with or without urge urinary incontinence (UUI), is the predominant characterization of overactive bladder (OAB). Despite a similar prevalence of OAB between both women and men (respectively 17% and 16%), the disproportionate effects of the most bothersome symptoms of UUI fall to women. In addition, OAB’s prevalence in women increases with age when compared with men, leading to decreased scores in quality of life (QoL) measures, sexual function, depression, and sleep quality. Although behavioral therapies such as bladder training and pelvic floor muscle exercises are recommended as the first-line treatment of OAB symptom management, other treatments do exist. These second-line treatments, such as anticholinergics, are commonly prescribed as treatment for these conditions, but their use also entails persistence-limiting adverse effects. Such adverse effects include risk of dementia and cognitive impairment. The American Urogynecologic Society recommends alternative medication consideration for all patients and outright avoidance of anticholinergics for OAB treatment in women older than 70 years. Vibegron, a selective b3-adrenergic receptor agonist, was approved in 2020 for adult OAB treatment. The EMPOWUR trial, the international, placebo- and active-controlled, randomized, double-blind, phase 3 trial, demonstrated over the course of 12 weeks both the efficacy and safety of both vibegron and tolterodine for adults with OAB. Based on the disproportionate nature and bother of OAB symptoms in women, this study intended to analyze subgroups of the EMPOWUR trial to compare the QoL outcomes, 12-week treatment safety, and efficacy of vibegron treatment in women. End points for coprimary efficacy were altered from baseline at week 12 in mean daily number of UUI episodes and micturitions. Secondary efficacy end points included daily number of urgency episodes (also week 12). Exploratory outcomes included change from baseline at weeks 2, 4, and 8 for the same factors. The full set analysis for this study included all women (randomized) receiving greater than 1 dose of vibegron or placebo who experienced greater than 1 measured change using baseline valuations of urgency episodes, micturitions, and QoL outcomes unrelated to incontinence. A total of 1515 patients were included in the safety set, 1289 (84.9%) of which were women (placebo, n = 459; vibegron, n = 463; tolterodine, n = 364), with the mean age being 59.5 years. The study determined that vibegron was associated with a statistically significant greater reduction among women from baseline at week 12 in comparison to placebo. QoL also improved significantly across the board, including total, concern, sleep, coping, and symptom bother subscale scores compared with placebo. Treatment emergent adverse effects incidence was 39.3% with vibegron, 34.9% with placebo, and 39.6% with tolterodine, leading to 1.5%, 1.1%, and 3.8% of women, respectively, discontinuing treatment. The most common treatment emergent adverse effects reported was headache. An analytical limitation was the relatively brief study period of 12 weeks. The double-blind 40-week extension of the EMPOWUR trial (52 total treatment weeks) substantiated long-term safety and efficacy of vibegron (J Urol. 2021;205:1421–1429). Although a relatively high placebo response rate was observed (consistent with other analyses), vibegron was still associated with statistically significant improvements when compared with placebo in OAB symptoms in women. This subgroup analysis of OAB-diagnosed women yielded results consistent with those of the EMPOWUR 12-week trial, which indicated statistically significant reductions versus placebo in efficacy end points with once-daily vibegron 75 mg. The results also showed favorable safety and tolerability profiles. Vibegron treatment among women with OAB also significantly improved measures of QoL versus placebo. All results therefore indicate the efficacy and safety of treatment of women’s OAB with vibegron.

Dynamic Feedback Between Antidepressant Placebo Expectancies and Mood

Despite high antidepressant placebo response rates, the mechanisms underlying the persistence of antidepressant placebo effects are still poorly understood. To investigate the neurobehavioral mechanisms underlying the evolution of antidepressant placebo effects using a reinforcement learning (RL) framework. In this acute within-patient cross-sectional study of antidepressant placebos, patients aged 18 to 55 years not receiving medication for major depressive disorder (MDD) were recruited at the University of Pittsburgh between February 21, 2017, to March 1, 2021. The antidepressant placebo functional magnetic resonance imaging task manipulates placebo-associated expectancies using visually cued fast-acting antidepressant infusions and controls their reinforcement with sham visual neurofeedback while assessing expected and experienced mood improvement. The trial-by-trial evolution of expectancies and mood was examined using multilevel modeling and RL, relating model-predicted signals to spatiotemporal dynamics of blood oxygenation level-dependent (BOLD) response. A bayesian RL model comparison in 60 individuals (mean [SE] age, 24.5 [0.8] years; 51 females [85%]) with MDD revealed that antidepressant placebo trial-wise expectancies were updated by composite learning signals multiplexing sensory evidence (neurofeedback) and trial-wise mood (bayesian omnibus risk <0.001; exceedance probability = 97%). Placebo expectancy, neurofeedback manipulations, and composite learning signals modulated the visual cortex and dorsal attention network (threshold-free cluster enhancement [TFCE] = 1 - P >.95). As participants anticipated antidepressant infusions, learned placebo expectancies modulated the salience network (SN, TFCE = 1 - P >.95), positively scaling with depression severity. Results of this cross-sectional study suggest that on a timescale of minutes, antidepressant placebo effects were maintained by positive feedback loops between expectancies and mood improvement. During learning, representations of placebos and their perceived effects were enhanced in primary and secondary sensory cortices. Latent learned placebo expectancies were encoded in the SN.

Meta-analysis: Placebo rates in microscopic colitis randomised trials and applications for future drug development using a historical control arm.

Effective medical therapies for patients with microscopic colitis (MC) who fail budesonide are lacking. However, conducting randomised controlled trials (RCTs) in MC has been challenging due to small sample sizes. Understanding placebo responses can help inform more efficient future trials. The aim of this study is to estimate clinical and histologic placebo response rates and to determine factors associated with placebo response in MC. EMBASE, MEDLINE, and CENTRAL were searched until 7 January 2022, to identify placebo-controlled RCTs in adult patients with MC. Clinical and histologic response in the placebo arms were pooled using random-effects models. Stratified analyses based on disease- and trial-level characteristics, leave-one-out meta-analysis, and cumulative meta-analysis were performed. Twelve RCTs enrolling a total of 391 patients (placebo n= 163) with MC were included. Pooled clinical and histologic placebo response rates were 24.4% (95% CI: 12.4%-38.4%), I2 = 60.8%, p < 0.01, and 19.9% (95% CI: 5.3%-39.0%), I2 = 66.4%, p= 0.01 (tests for heterogeneity), respectively. Clinical response to placebo was numerically higher in patients with lymphocytic compared to collagenous colitis (39.9% vs. 19.8%, p=0.08). Heterogeneity in clinical response to placebo was significantly reduced when the Miehlke 2014 RCT was excluded in the leave-one-out meta-analysis or when a more stringent secondary definition of response based on the Hjortswang criteria was applied. Approximately one-quarter of patients in MC trials respond to placebo, although with substantial heterogeneity, reflecting the need for standardised outcome definitions and study designs for MC. This analysis also serves to inform future MC trials that may consider incorporating an external, historical placebo control arm, rather than directly randomising patients to placebo.