Multicentre trials: a US regulatory perspective

Kidney Injury After Minimal Radiographic Contrast Administration in Patients With Acute Coronary Syndromes

BACKGROUND

Acute kidney injury (AKI) is common in patients with acute coronary syndromes (ACS) treated by percutaneous coronary intervention.

OBJECTIVES

Contrast media (CM) volume minimization has been advocated for prevention of AKI. The DyeVert CM diversion system (Osprey Medical, Inc) is designed to reduce CM volume during coronary procedures.

METHODS

In this randomized, single-blind, investigator-driven clinical trial conducted in 4 Italian centers from February 4, 2020 to September 13, 2022, 550 participants with ACS were randomly assigned in a 1:1 ratio to the following: 1) the contrast volume reduction (CVR) group (n = 276), in which CM injection was handled by the CM diversion system; and 2) the control group (n = 274), in which a conventional manual or automatic injection syringe was used. The primary endpoint was the rate of AKI, defined as a serum creatinine (sCr) increase ≥0.3 mg/dL within 48 hours after CM exposure.

RESULTS

There were 412 of 550 (74.5%) participants with ST-segment elevation myocardial infarction (211 of 276 [76.4%] in the CVR group and 201 of 274 [73.3%] in the control group). The CM volume was lower in the CVR group (95 ± 30 mL vs 160 ± 23 mL; P < 0.001). Seven participants (1 in the CVR group and 6 in the control group) did not have postprocedural sCr values. AKI occurred in 44 of 275 (16%) participants in the CVR group and in 65 of 268 (24.3%) participants in the control group (relative risk: 0.66; 95% CI: 0.47-0.93; P = 0.018).

CONCLUSIONS

CM volume reduction obtained using the CM diversion system is effective for prevention of AKI in patients with ACS undergoing invasive procedures. (REnal Insufficiency Following Contrast MEDIA Administration TriaL IV [REMEDIALIV]: NCT04714736).

Left Ventricular End-Diastolic Pressure Versus Urine Flow Rate-Guided Hydration in Preventing Contrast-Associated Acute Kidney Injury

OBJECTIVES

This study compared left ventricular end-diastolic pressure (LVEDP)-guided and urine flow rate (UFR)-guided hydration.

BACKGROUND

Tailored hydration regimens improve the prevention of contrast-associated acute kidney injury (CA-AKI).

METHODS

Between July 15, 2015, and June 6, 2019, patients at high risk for CA-AKI scheduled for coronary and peripheral procedures were randomized to 2 groups: 1) normal saline infusion rate adjusted according to the LVEDP (LVEDP-guided group); and 2) hydration controlled by the RenalGuard System in order to reach UFR ≥300 ml/h (UFR-guided group). The primary endpoint was the composite of CA-AKI (i.e., serum creatinine increase ≥25% or ≥0.5 mg/dl at 48 h) and acute pulmonary edema (PE). Major adverse events (all-cause death, renal failure requiring dialysis, PE, and sustained kidney injury) at 1 month were assessed.

RESULTS

The primary endpoint occurred in 20 of 351 (5.7%) patients in the UFR-guided group and in 36 of 351 (10.3%) patients in the LVEDP-guided group (relative risk [RR]: 0.560; 95% confidence interval [CI]: 0.390 to 0.790; p = 0.036). CA-AKI and PE rates in the UFR-guided group and LVEDP-guided group were 5.7% and 10.0% (RR: 0.570; 95% CI: 0.300 to 0.960; p = 0.048), and, respectively, 0.3% and 2.0% (RR: 0.070; 95% CI: 0.020 to 1.160; p = 0.069). Three patients in the UFR-guided group experienced complications related to the Foley catheter. Hypokalemia rate was 6.2% in the UFR-guided group and 2.3% in the LVEDP-guided group (p = 0.013). The 1-month major adverse events rate was 7.1% in the UFR-guided group and 12.0% in the LVEDP-guided group (p = 0.030).

CONCLUSIONS

The study demonstrates that UFR-guided hydration is superior to LVEDP-guided hydration to prevent the composite of CA-AKI and PE.

Clustering by Health Professionals in Individually Randomised Controlled Trials

Purpose: The aim of this study was to investigate the prevalence of clustering by health professionals in individually randomised controlled trials (iRCT), and its adjustment in both the sample size calculation estimates and the analysis of the data collected in iRCT (that is, trials that randomise individuals only). As a result, cluster randomised controlled trials will not be the part of this review study. Additionally, the authors aimed to discover the prevalence of the various forms of clustering in iRCT. Methods: iRCT, in which the intervention was delivered by a health professional, were electronically searched in three medical journals. The dates searched were from 1st January 2000–31st August 2009. The retrieved trials were then screened to exclude those with complex designs and trials with more than two parallel arms. The selected trials were then fully reviewed for the presence of clustering effects and any corresponding adjustment. Data about the sample size calculation in the selected trials were also included. A basic form was generated for the purpose of data extraction from each of the selected trials. Results: Of the 130 iRCT reviewed, clustering of outcomes was present in 127 (98%) trials. Only 61 trials (47%) had adjusted for the clustering effects in their design and analysis, while 53% of the trials had ignored the clustering effect, and hence no adjustment had been made in the trial design or analysis. Regarding the various forms of clustering, clustering by centre in multicentre trials was found in 79 trials (60%), followed by natural clustering in 26 trials (20%), and clustering imposed by the design of the study in 23 trials (18%). Conclusion: Potential clustering of outcomes exists in almost all iRCT; however, this review found that <50% of iRCT took clustering into account and adjusted the sample size calculation and statistical analysis of this data for clustering. Almost half of the reviewed iRCT ignored the clustering effect. As a result, inaccurate and nongeneralisable results could have been generated.

Longitudinal multi-centre brain imaging studies: guidelines and practical tips for accurate and reproducible imaging endpoints and data sharing

Background

Research involving brain imaging is important for understanding common brain diseases. Study endpoints can include features and measures derived from imaging modalities, providing a benchmark against which other phenotypical data can be assessed. In trials, imaging data provide objective evidence of beneficial and adverse outcomes. Multi-centre studies increase generalisability and statistical power. However, there is a lack of practical guidelines for the set-up and conduct of large neuroimaging studies.

Methods

We address this deficit by describing aspects of study design and other essential practical considerations that will help researchers avoid common pitfalls and data loss.

Results

The recommendations are grouped into seven categories: (1) planning, (2) defining the imaging endpoints, developing an imaging manual and managing the workflow, (3) performing a dummy run and testing the analysis methods, (4) acquiring the scans, (5) anonymising and transferring the data, (6) monitoring quality, and (7) using structured data and sharing data.

Conclusions

Implementing these steps will lead to valuable and usable data and help to avoid imaging data wastage.

Comparable efficacy and safety of 8 weeks treatment with agomelatine 25-50mg or fluoxetine 20-40mg in Asian out-patients with major depressive disorder

OBJECTIVE

This randomized, double-blind study evaluates the efficacy and tolerability of agomelatine, using fluoxetine as an active comparator, in Asian patients suffering from moderate to severe major depressive disorder (MDD).

METHOD

Patients were randomly assigned to receive either agomelatine (25-50mg/day, n=314) or fluoxetine (20-40mg/day, n=314) during an 8-week treatment period. The main outcome measure was the change in Hamilton Depression Rating Scale 17 items (HAM-D17) scores. Secondary efficacy criteria included scores on Clinical Global Impression Severity of illness (CGI-S) and Improvement of illness (CGI-I), patient sleeping improvement using the self-rating Leeds Sleep Evaluation Questionnaire (LSEQ) and anxiety using the Hamilton Anxiety Rating Scale (HAM-A) scores. Tolerability and safety evaluations were based on emergent adverse events.

RESULTS

Agomelatine and fluoxetine exert a comparable antidepressant efficacy in the Asian population. Mean changes over 8 weeks were clinically relevant and similar in both groups (-14.8±7.3 and -15.0±8.1 on HAM-D17 scale in agomelatine and fluoxetine groups, respectively). The between-group difference reached statistical significance on non-inferiority test (p=0.015). Clinically relevant decreases in CGI-S and CGI-I scores were observed over the treatment period in both groups. The two treatments were equally effective on the symptoms of both anxiety and sleep. The good tolerability profile and safety of both doses of agomelatine was confirmed in the Asian population.

CONCLUSIONS

Agomelatine and fluoxetine are equally effective in the treatment of MDD-associated symptoms in Asian depressed patients.

Renal Insufficiency After Contrast Media Administration Trial II (REMEDIAL II): RenalGuard System in high-risk patients for contrast-induced acute kidney injury

BACKGROUND

The RenalGuard System, which creates high urine output and fluid balancing, may be beneficial in preventing contrast-induced acute kidney injury.

METHODS AND RESULTS

The Renal Insufficiency After Contrast Media Administration Trial II (REMEDIAL II) trial is a randomized, multicenter, investigator-driven trial addressing the prevention of contrast-induced acute kidney injury in high-risk patients. Patients with an estimated glomerular filtration rate ≤30 mL · min(-1) · 1.73 m(-2) and/or a risk score ≥11 were randomly assigned to sodium bicarbonate solution and N-acetylcysteine (control group) or hydration with saline and N-acetylcysteine controlled by the RenalGuard System and furosemide (RenalGuard group). The primary end point was an increase of ≥0.3 mg/dL in the serum creatinine concentration at 48 hours after the procedure. The secondary end points included serum cystatin C kinetics and rate of in-hospital dialysis. Contrast-induced acute kidney injury occurred in 16 of 146 patients in the RenalGuard group (11%) and in 30 of 146 patients in the control group (20.5%; odds ratio, 0.47; 95% confidence interval, 0.24 to 0.92). There were 142 patients (48.5%) with an estimated glomerular filtration rate ≤30 mL · min(-1) · 1.73 and 149 patients (51.5%) with only a risk score ≥11. Subgroup analysis according to inclusion criteria showed a similarly lower risk of adverse events (estimated glomerular filtration rate ≤30 mL · min(-1) · 1.73 m(-2): odds ratio, 0.44; risk score ≥11: odds ratio, 0.45; P for interaction=0.97). Changes in cystatin C at 24 hours (0.02±0.32 versus -0.08±0.26; P=0.002) and 48 hours (0.12±0.42 versus 0.03±0.31; P=0.001) and the rate of in-hospital dialysis (4.1% versus 0.7%; P=0.056) were higher in the control group.

CONCLUSION

RenalGuard therapy is superior to sodium bicarbonate and N-acetylcysteine in preventing contrast-induced acute kidney injury in high-risk patients.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrial.gov. Unique identifier: NCT01098032.

A Gaussian Copula Model for Multivariate Survival Data

We consider a Gaussian copula model for multivariate survival times. Estimation of the copula association parameter is easily implemented with existing software using a two-stage estimation procedure. Using the Gaussian copula, we are able to test whether the association parameter is equal to zero. When the association term is positive, the model can be extended to incorporate cluster-level frailty terms. Asymptotic properties are derived under the two-stage estimation scheme. Simulation studies verify finite sample utility. We apply the method to a Children's Oncology Group multi-center study of acute lymphoblastic leukemia. The analysis estimates marginal treatment effects and examines potential clustering within treatment institution.

Blinded sample size recalculation in multicentre trials with normally distributed outcome

The internal pilot study design enables to estimate nuisance parameters required for sample size calculation on the basis of data accumulated in an ongoing trial. By this, misspecifications made when determining the sample size in the planning phase can be corrected employing updated knowledge. According to regulatory guidelines, blindness of all personnel involved in the trial has to be preserved and the specified type I error rate has to be controlled when the internal pilot study design is applied. Especially in the late phase of drug development, most clinical studies are run in more than one centre. In these multicentre trials, one may have to deal with an unequal distribution of the patient numbers among the centres. Depending on the type of the analysis (weighted or unweighted), unequal centre sample sizes may lead to a substantial loss of power. Like the variance, the magnitude of imbalance is difficult to predict in the planning phase. We propose a blinded sample size recalculation procedure for the internal pilot study design in multicentre trials with normally distributed outcome and two balanced treatment groups that are analysed applying the weighted or the unweighted approach. The method addresses both uncertainty with respect to the variance of the endpoint and the extent of disparity of the centre sample sizes. The actual type I error rate as well as the expected power and sample size of the procedure is investigated in simulation studies. For the weighted analysis as well as for the unweighted analysis, the maximal type I error rate was not or only minimally exceeded. Furthermore, application of the proposed procedure led to an expected power that achieves the specified value in many cases and is throughout very close to it.

Sample size and proportion of Japanese patients in multi-regional trials

In recent years, multi-regional trials have received increasing attention by pharmaceutical companies carrying out global drug development programs. In Japan, new drugs are often approved several years after market release in other countries. The recently published guidance on 'Basic Principles on Global Clinical Trials' addresses specifically this time lag. A multi-regional trial has at least two main objectives. First, it is necessary to show a significant benefit in effect of a new drug in the entire population. Second, one needs to demonstrate that the results for a particular region are consistent with those from the entire population. In this paper, we discuss the methods proposed in the Japanese regulatory guidance document and derive closed form expressions for the resulting probabilities, which require the evaluation of multivariate normal or t probabilities. In addition, we propose an alternative method with better operating characteristics than the current approaches. Moreover, we examine the performance of our suggested method by simulating the probability of achieving the objectives and calculating the false-positive error rate.

Effect of ropinirole on sleep outcomes in patients with restless legs syndrome: meta-analysis of pooled individual patient data from randomized controlled trials

STUDY OBJECTIVE

To compare the effects of ropinirole with those of placebo on sleep, as evaluated by specific domains of the Medical Outcomes Study (MOS) sleep scale, as well as the Clinical Global Impression-Improvement (CGI-I) scale, in patients with restless legs syndrome (RLS).

DESIGN

Meta-analysis of six randomized, double-blind, placebo-controlled, parallel-group trials conducted in the United States and Europe.

PATIENTS

A total of 1679 patients aged 18-79 years with primary moderate-to-severe RLS who received ropinirole (835 patients) or placebo (844 patients).

MEASUREMENTS AND MAIN RESULTS

A systematic review of MEDLINE (January 1980-January 2007) and clinical trial registers was performed to identify placebo-controlled trials of ropinirole that used the 12-item MOS sleep scale to assess sleep in patients with RLS. Individual patient data from both published and nonpublished trials were pooled for meta-analysis. In the eligible studies, immediate-release ropinirole 0.25-6 mg or placebo had been given for at least 12 weeks. In addition, sleep scale summary scores for the domains of sleep quantity, adequacy, disturbance, and daytime somnolence had to have been assessed at baseline and at 12 weeks. Our meta-analysis found that at baseline study patients slept an average of 5.8 hours/night. At the end of 12 weeks, ropinirole-treated patients slept a mean of 2.5 hours/week more and had a 21% greater improvement from baseline in sleep adequacy scores compared with patients receiving placebo. Ropinirole-treated patients also had 14% less sleep disturbance and 8% less daytime somnolence than patients receiving placebo. Clinicians rated 63% of ropinirole-treated patients and 47% of patients receiving placebo as responders based on the CGI-I scale. Mixed effects analysis of covariance was used to estimate treatment effect adjusting for study center as a random effect, as well as the following fixed effects known to affect sleep: baseline sleep characteristics, age, sex, and chronic medical conditions. All differences were statistically significant (p<0.05), even after adjusting for multiple comparisons.

CONCLUSION

Pooled data from six similarly designed clinical trials provide evidence that ropinirole improves sleep quantity and adequacy, and lessens sleep disturbance and daytime somnolence in patients with primary RLS.

[From ethnic difference to ethnic similarity]

It becomes the important issue for the medical supplies administration to solve the drug lag in our country. As means to overcome both the slow speed and high cost of clinical trial for new drug application in Japan, it seems useful to carry out clinical development simultaneously in East Asia countries such as China, Korea and Taiwan where it is thought that each country has similar ethnicity one another. When conducting simultaneous development with the same protocol in plural countries, it should be avoided that side effect develops abusively. In addition, both the effectiveness and safety expected after marketing should be secured in each country by a recommended amount of medicine for usage provided by simultaneous development between many countries. It is necessary for ethnic similarity to be shown so that development between the many countries in the same dosage is permitted at least. It is expected that the possibility of mutual utilization of clinical trial data of China, Korea and Japan will be shown by pharmacokinetics and pharmacodynamics examinations based on clinical test data of these countries by the Scientific Research funded by MHLW. On the other hand, it seems that it is meaningful and significant to examine the similarity at the gene level from various points of view. In order to give grounds for the validity of carrying out clinical trial in the same protocol in East Asia countries, it may be useful to examine genetic diversity of East Asia countries with plural heredity anthropological techniques such as heredity distance, and compare degree of the genetic diversity between the races of East Asia countries and that of other regions, for example, West Europe countries which have been recognized as one clinical trial field.

Baseline and treatment effect heterogeneity for survival times between centers using a random effects accelerated failure time model with flexible error distribution

Nowadays, most clinical trials are conducted in different centers and even in different countries. In most multi-center studies, the primary analysis assumes that the treatment effect is constant over centers. However, it is also recommended to perform an exploratory analysis to highlight possible center by treatment interaction, especially when several countries are involved. We propose in this paper an exploratory Bayesian approach to quantify this interaction in the context of survival data. To this end we used and generalized a random effects accelerated failure time model. The generalization consists in using a penalized Gaussian mixture as an error distribution on top of multivariate random effects that are assumed to follow a normal distribution. For computational convenience, the computations are based on Markov chain Monte Carlo techniques. The proposed method is illustrated on the disease-free survival times of early breast cancer patients collected in the EORTC trial 10854.

Globalization of the Radiation Therapy Oncology Group: implementation of a model for service expansion and public health improvement

The Radiation Therapy Oncology Group (RTOG) is part of the cooperative group network that is overseen by the National Cancer Institute (NCI). Although the NCI is a US-based group, it has empowered the cooperative groups to recruit foreign institutions to participate in collaborative clinical trials. The RTOG undertook the challenge of globalizing its efforts in 2004. This article describes the rationale for this decision and the tactics adopted by the first hospital outside of North America to enroll patients onto RTOG trials. The challenges confronted by foreign institutions seeking admission to the RTOG and the mechanism by which Tel Aviv Medical Center (TAMC) met these challenges are described. Shortly after its acceptance, TAMC emerged as one of the leading accruers of patients to RTOG studies. The public health implications of this accomplishment are discussed.

Sample size calculation for multicenter randomized trial: Taking the center effect into account

In multicenter trials, data from the same center are more similar than those from different centers. These similarities induce a correlation between data, known as the center effect, which is assessed by the intraclass correlation coefficient (ICC). Here, we derive a sample size formula for continuous data that takes into account this center effect. Our analytical developments lead to an elementary formula different from the classical one by a (1-rho) factor, where rho is the ICC. This work allows for adjusting and reducing the sample size according to the magnitude of the center effect and leads to a better consistency in the conduct of multicenter randomized trials.

Modelling to extract more information from clinical trials data: On some roles for the bootstrap

Despite its importance in the theoretical literature, the bootstrap appears to play a negligible role in pharmaceutical research, as will be demonstrated by a brief literature review. As will be shown by examples, the bootstrap is a useful tool in the planning and analysis of clinical trials. The first example shows that some important information required in the design of a study can best be gained by using the bootstrap. It is argued from two further examples that more information can be extracted from large clinical trials by data-dependent modelling. This is shown by identifying a prognostic factor that may play a role as an inclusion criterion of a new study and by an interaction of a continuous predictor with treatment. To protect against erroneous conclusions from data-dependent modelling in a multivariable context, detailed checks of the results and stability analyses should be performed by the bootstrap. To conclude, a discussion of the future of modelling and the future of the bootstrap is given.