Unlocking the Potential: A Systematic Review of Master Protocol in Pediatrics.

The use of master protocols allows for innovative approaches to clinical trial designs, potentially enabling new approaches to operations and analytics and creating value for patients and drug developers. Pediatric research has been conducted for many decades, but the use of novel designs such as master protocols in pediatric research is not well understood. This study aims to provide a systematic review on the utilization of master protocols in pediatric drug development. A search was performed in September 2022 using two data sources (PubMed and ClinicalTrials.gov) and included studies conducted in the past10 years. General study information was extracted such as study type, study status, therapeutic area, and clinical trial phase. Study characteristics that are specific to pediatric studies (such as age of the participants and pediatric drug dosing) and important study design elements (such as number of test drug arms and whether randomization and/or concurrent control was used) were also collected. Our results suggest that master protocol studies are being used in pediatrics, with platform and basket trials more common than umbrella trials. Most of this experience is in oncology and early phase studies. There is a rise in the use starting in 2020, largely in oncology and COVID-19 trials. However, adoption of master protocols in pediatric clinical research is still on a small scale and could be substantially expanded. Work is required to further understand the barriers in implementing pediatric master protocols, from setting up infrastructure to interpreting study findings.

The Addition of Sirolimus to GVHD Prophylaxis After Allogeneic Hematopoietic Stem Cell Transplantation: A Meta-Analysis of Efficacy and Safety.

OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of sirolimus (SRL) in the prevention of graft-versus-host disease (GVHD) in recipients following allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: Randomized controlled trials (RCTs) evaluating the safety and efficacy of SRL-based prophylaxis regimens in patients receiving allo-HSCT were obtained from PubMed, Embase, and the Cochrane database. Following specific inclusion and exclusion criteria, studies were selected and screened by two independent reviewers who subsequently extracted the study data. The Cochrane risk bias evaluation tool was used for quality evaluation, and RevMan 5.3 software was used for statistical analysis comparing the effects of SRL-based and non-SRL-based regimens on acute GVHD, chronic GVHD, overall survival (OS), relapse rate, non-relapse mortality (NRM), thrombotic microangiopathy (TMA), and veno-occlusive disease (VOD). RESULTS: Seven studies were included in this meta-analysis, with a total sample size of 1,673 cases, including 778 cases of patients receiving SRL-based regimens and 895 cases in which patients received non-SRL-based regimens. Our data revealed that SRL containing prophylaxis can effectively reduce the incidence of grade II-IV acute GVHD (RR = 0.75, 95% CI: 0.68∼0.82, p < 0.0001). SRL-based prophylaxis was not associated with an improvement of grade III-IV acute GVHD (RR = 0.78, 95% CI: 0.59∼1.03, p = 0.08), chronic GVHD (p = 0.89), OS (p = 0.98), and relapse rate (p = 0.16). Despite its immunosuppressant effects, SRL-based regimens did not increase bacterial (p = 0.68), fungal (p = 0.70), or CMV (p = 0.10) infections. However, patients receiving SRL-based regimens had increased TMA (p < 0.00001) and VOD (p < 0.00001). CONCLUSIONS: This meta-analysis indicates that addition of sirolimus is an effective alternative prophylaxis strategy for II-IV aGVHD but may cause endothelial cell injury and result in secondary TMA or VOD events.

Enhancing clarity of clinical trial safety reports for data monitoring committees.

A Data Monitoring Committee (DMC) evaluates patient safety in a clinical trial of an investigational intervention through periodic review of adverse events (AEs) and clinical safety assessments. Our aim was to construct DMC report displays to enhance the DMC safety review through use of graphics and clear identification and adjustment for missing data caused by early discontinuations and ongoing study participation. Suggested displays include a study snapshot graph, enhanced adverse event incidence tables including the incidence density and plotted incidence proportions, line graphs in place of by-patient listings, and trend plots in place of tables for continuous assessments.

Hepatitis C Virus RNA Levels Following Virologic Failure With Direct-acting Antivirals: Implications for Lower Sensitivity Diagnostic Assays.

We analyzed post-treatment hepatitis C virus (HCV) RNA levels from 330 subjects who experienced virologic failure in clinical trials of direct-acting antivirals. We demonstrated that 97% had post-treatment Week 12 HCV RNA >10 000 IU/mL, above reported sensitivity limits of novel diagnostic assays being considered for simplified HCV treatment monitoring.

[Effect of an Aerobic Unit and a Sedimentation Unit on Sludge and Nitrogen Removal in an Anoxic Unit in a Continuous-flow System].

Using an A2/O process with three dissolved oxygen (DO) levels[3.0-3.5 mg·L-1(Ⅰ stage), 2.0-2.5 mg·L-1(Ⅱ stage), 1.5-2.0 mg·L-1(Ⅲ stage)], the sludge and denitrification characteristics of its aerobic unit and sedimentation unit were investigated and compared with that of an anoxic-aerobic (A/O) process with a DO content of 1.5-2.0 mg·L-1. The results showed that denitrification in the sedimentation unit was accomplished with both internal and external carbon sources, but sludge's denitrification was more efficient with the use of external carbon sources. Nitrate reductase activity and denitrification activity in the sludge in sedimentation unit were highest when DO content was 1.5-2.0 mg·L-1 under aerobic conditions, and the denitrification efficiency of the A2/O process was greatest under anoxic conditions. The residual PHB in the aerobic A/O process was higher than that in the A2/O process with experimental sludge loading. The denitrification activity of the sludge in the A/O process was higher, and the nitrate reductase activity was 1.08 times higher than that in the A/O process. After returnning of the sludge, denitrification in the anoxic A/O process was poor, although the removal of nitrate nitrogen was sufficient. In comparison, denitrification in the anoxic unit of the A2/O process was better. Denitrification of the sludge in the sedimentation unit was directly related to denitrification in the anoxic unit. Therefore, to ensure that denitrification in sedimentation unit does not seriously affect the separation of sludge and water, appropriate control of the aerobic operation and the maintenance of denitrification in the sedimentation unit will contribute more to the denitrification efficiency of the system rather than simply controlling the level of anoxia.

Calibration of activity-related energy expenditure in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

OBJECTIVES: Usual physical activity (PA) is a complex exposure and typical instruments to measure aspects of PA are subject to measurement error, from systematic biases and biological variability. This error can lead to biased estimates of associations between PA and health outcomes. We developed a calibrated physical activity measure that adjusts for measurement error in both self-reported and accelerometry measures of PA in adults from the US Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a community-based cohort study. DESIGN: Total energy expenditure (TEE) from doubly labeled water and resting energy expenditure (REE) from indirect calorimetry were measured in 445 men and women aged 18-74years in 2010-2012, as part of the HCHS/SOL Study of Latinos: Nutrition & Physical Activity Assessment Study (SOLNAS). Measurements were repeated in a subset (N=98) 6months later. METHOD: Calibration equations for usual activity-related energy expenditure (AEE=0.90×TEE-REE) were developed by regressing this objective biomarker on self-reported PA and sedentary behavior, Actical accelerometer PA, and other subject characteristics. RESULTS: Age, weight and height explained a significant amount of variation in AEE. Actical PA and wear-time were important predictors of AEE; whereas, self-reported PA was not independently associated with AEE. The final calibration equation explained fifty percent of variation in AEE. CONCLUSIONS: The developed calibration equations can be used to obtain error-corrected associations between PA and health outcomes in HCHS/SOL. Our study represents a unique opportunity to understand the measurement characteristics of PA instruments in an under-studied Hispanic/Latino cohort.

Statistical planning in confirmatory clinical trials with multiple treatment groups, multiple visits, and multiple endpoints.

Multiplicity issues can be multidimensional: A confirmatory clinical trial may be designed to have efficacy assessed with two or more primary endpoints, for multiple dose groups, and at several post-baseline visits. Controlling for multiplicity in this situation is challenging because there can be a hierarchy with respect to some but not all measurements. If the higher dose is considered more efficacious, multiplicity approach may evaluate the higher dose with higher priority through a fixed sequential testing framework for dose assessments in combination with a Hochberg approach for endpoints. The lower dose is only assessed when the higher dose has significant results, which reduces the power for detecting signals in the lower dose group. However, in some instances the higher dose may associate with tolerability or safety concerns that preclude regulatory approval. A real confirmatory clinical trial with such challenges is provided as an illustrative example. We discuss closed testing procedures based on multi-way averages of comparisons for this complex multiplicity situation through illustrative case analyses and a simulation study. Such strategies manage the higher dose and the lower dose with equal priority, and they enable evaluation of the multiple endpoints at multiple visits collectively with power being reasonably high.

Statistical planning to address strongly correlated endpoints for inferential subgroups: An innovative approach for an illustrative clinical trial with complex multiplicity issues.

Multiplicity is an important statistical issue that arises in clinical trials when the efficacy of the test treatment is evaluated in multiple ways. The major concern for multiplicity is that uncontrolled multiple assessments lead to inflated family-wise Type I error, and they thereby undermine the integrity of the statistical inferences. Multiplicity comes from different sources, for example, making inferences either on the overall population or some pre-specified sub-populations, while multiple endpoints need to be evaluated for each population. Therefore, a sound statistical strategy that controls the family-wise Type I error rate in a strong sense, without excessive loss of power from over-control, is crucial for the success of the trial. For a recent phase III cardiovascular trial with such complex multiplicity, we illustrate the use of a closed testing strategy that begins with a global test; and subsequent testing only proceeds when the global test is rejected. Also, we discuss a simulation study based on this trial to compare the power of the illustrated closed testing strategy to some well-known alternative approaches. We found that this strategy can comprehensively meet most of the primary objectives of the trial effectively with reasonably high overall power.

Analyzing multiple endpoints in a confirmatory randomized clinical trial-an approach that addresses stratification, missing values, baseline imbalance and multiplicity for strictly ordinal outcomes.

Confirmatory randomized clinical trials with a stratified design may have ordinal response outcomes, ie, either ordered categories or continuous determinations that are not compatible with an interval scale. Also, multiple endpoints are often collected when 1 single endpoint does not represent the overall efficacy of the treatment. In addition, random baseline imbalances and missing values can add another layer of difficulty in the analysis plan. Therefore, the development of an approach that provides a consolidated strategy to all issues collectively is essential. For a real case example that is from a clinical trial comparing a test treatment and a control for the pain management for patients with osteoarthritis, which has all aforementioned issues, multivariate Mann-Whitney estimators with stratification adjustment are applicable to the strictly ordinal responses with stratified design. Randomization based nonparametric analysis of covariance is applied to account for the possible baseline imbalances. Several approaches that handle missing values are provided. A global test followed by a closed testing procedure controls the family wise error rate in the strong sense for the analysis of multiple endpoints. Four outcomes indicating joint pain, stiffness, and functional status were analyzed collectively and also individually through the procedures. Treatment efficacy was observed in the combined endpoint as well as in the individual endpoints. The proposed approach is effective in addressing the aforementioned problems simultaneously and straightforward to implement.

Evaluating treatment efficacy by multiple end points in phase II acute heart failure clinical trials: analyzing data using a global method.

BACKGROUND: To assess concomitant simultaneous effects on multiple end points using global statistical methods in phase II acute heart failure studies. METHODS AND RESULTS: Using simulations we have assessed different statistical methods to evaluate concomitant effects of a new intervention on dyspnea relief (using 2 measures), length of hospital stay, worsening heart failure to 5 days, mortality, and heart failure readmission to 30 days. Treatment effect scenarios included large (20% to 28% relative improvements) and very large (30% to 43% relative improvements) effects among others. Placebo responses and correlations among end points typical in recent acute heart failure clinical trials were used. Powers for the average Z score exceeded 70% with ≥75 patients per group for 35% relative improvement across all 6 end points. Assessing dyspnea alone generally provides lower power than the average Z score approach, with power deducted ≈50% under most of scenarios. Other approaches generally provide lower power than the average Z score method. CONCLUSIONS: Assessing the effects of new therapies on multiple clinical end points using the average Z score enables detection of therapeutic efficacy using sample sizes of 100 to 150 patients per group, approximately double the power achievable assessing the effects on dyspnea alone.

Is worsening renal function an ominous prognostic sign in patients with acute heart failure? The role of congestion and its interaction with renal function.

BACKGROUND: Worsening renal function (WRF), traditionally defined as an increase in serum creatinine levels ≥0.3 mg/dL, is a frequent finding in patients with acute heart failure (AHF) and has been associated with poorer outcomes in some but not all studies. We hypothesized that these discrepancies may be caused by the interaction between WRF and congestion in AHF patients. METHODS AND RESULTS: We measured serum creatinine levels on a daily basis during the hospitalization and assessed the persistence of signs of congestion at discharge in 599 consecutive patients admitted at our institute for AHF. They had a postdischarge mortality and mortality or AHF readmission rates of 13% and 43%, respectively, after 1 year. Patients were subdivided into 4 groups according to the development or not of WRF and the persistence of ≥1 sign of congestion at discharge. Patients with WRF and no congestion had similar outcomes compared with those with no WRF and no congestion, whereas the risk of death or of death or AHF readmission was increased in the patients with persistent congestion alone and in those with both WRF and congestion (hazard ratio, 5.35; 95% confidence interval, 3.0-9.55 at univariable analysis; hazard ratio, 2.44; 95% confidence interval, 1.24-4.18 at multivariable analysis for mortality; hazard ratio, 2.14; 95% confidence interval, 1.39-3.3 at univariable analysis; and hazard ratio, 1.39; 95% confidence interval, 0.88-2.2 at multivariable analysis for mortality and rehospitalizations). CONCLUSIONS: WRF alone, when detected using serial serum creatinine measurements, is not an independent determinant of outcomes in patients with AHF. It has an additive prognostic value when it occurs in patients with persistent signs of congestion.

Neurohormonal activation in acute heart failure: results from VERITAS.

OBJECTIVES: Recent heart failure studies have suggested that inflammatory and immune system activation are associated with increased levels of cytokines, chemokines and inflammatory proteins during acutely decompensated heart failure. The objectives of this substudy were to evaluate the role of neurohormonal and inflammatory activation in the pathogenesis and outcome of acute heart failure (AHF) and the correlation between biomarker levels and clinical outcomes. METHODS: Serum levels of B-type natriuretic peptide-32 (BNP-32), endothelin-1 (ET-1), norepinephrine, troponins I and T, C-reactive protein (CRP), von Willebrand factor, plasminogen activator inhibitor-1, interleukin-6 (IL-6) and tissue plasminogen activator (TPA) were measured at baseline, 24 and 48 h and 7 and 30 days in 112 patients with AHF recruited to the Value of Endothelin Receptor Inhibition with Tezosentan in Acute Heart Failure Study neurohormonal substudy. RESULTS: On univariable analysis, CRP, BNP and ET-1 were predictive of worsening heart failure by day 30; when considered together, only CRP and BNP were significantly associated with this outcome. On adjustment for age, baseline blood pressure, serum sodium and serum creatinine, only age and BNP remained significant. CRP, IL-6 and TPA levels were significantly correlated with 180-day mortality on univariable analysis. CONCLUSION: Circulating markers of inflammation may be useful in gauging prognosis in patients with AHF.

Permutation criteria to evaluate multiple clinical endpoints in a proof-of-concept study: lessons from Pre-RELAX-AHF.

BACKGROUND: Clinically relevant endpoints cannot be routinely targeted with reasonable power in a small study. Hence, proof-of-concept studies are often powered to a primary surrogate endpoint. However, in acute heart failure (AHF) effects on surrogates have not translated into clinical benefit in confirmatory studies. Although observing an effect on one of many endpoints due to chance is likely, observing concurrent positive trends across several outcomes by chance is usually unlikely. METHODS: Pre-RELAX-AHF, which compared 4 relaxin doses with placebo in AHF, has shown favourable trends versus placebo (one-sided P < 0.10) on six of nine clinical endpoints in the 30 µg/kg/day group. To illustrate evaluation of multiple, correlated clinical endpoints for evidence of efficacy and for dose selection, a permutation method was applied retrospectively. By randomly re-assigning the treatment group to the actual data for each of the 229 subjects, 20,000 permutation samples were constructed. RESULTS: The permutation P value for at least six favourable trends among nine endpoints in any dose groups was 0.0073 (99.9% CI 0.0053-0.0093). This is higher than would be expected if the endpoints were uncorrelated (0.00026), but much lower than the probability of observing one of nine comparisons significant at the traditional two-sided P < 0.05 (0.74). Thus, the result was unlikely due to correlated endpoints or to chance. CONCLUSIONS: Examining consistency of effect across multiple clinical endpoints in a proof-of-concept study may identify efficacious therapies and enable dose selection for confirmatory trials. The merit of the approach described requires confirmation through prospective application in designing future studies.

Preclinical efficacy of a carboxylesterase 2-activated prodrug of doxazolidine.

Doxazolidine (Doxaz) is a functionally distinct formaldehyde conjugate of doxorubicin (Dox) that induces cancer cell death in Dox-sensitive and resistant cells. Pentyl PABC-Doxaz (PPD) is a prodrug of Doxaz that is activated by carboxylesterase 2 (CES2), which is expressed by liver, non-small-cell lung, colon, pancreatic, renal, and thyroid cancer cells. Here, we demonstrate that in two murine models, PPD was effective at slowing tumor growth and demonstrated markedly reduced cardiotoxic and nephrotoxic effects, as well as better tolerance, relative to Dox. Hepatotoxicity, consistent with liver expression of the murine CES2 homologue, was induced by PPD. Unlike irinotecan, a clinical CES2-activated prodrug, PPD produced no visible gastrointestinal damage. Finally, we demonstrate that cellular response to PPD may be predicted with good accuracy using CES2 expression and Doxaz sensitivity, suggesting that these metrics may be useful as clinical biomarkers for sensitivity of a specific tumor to PPD treatment.

17beta-Estradiol inhibits Ca2+-dependent homeostasis of airway surface liquid volume in human cystic fibrosis airway epithelia.

Normal airways homeostatically regulate the volume of airway surface liquid (ASL) through both cAMP- and Ca2+-dependent regulation of ion and water transport. In cystic fibrosis (CF), a genetic defect causes a lack of cAMP-regulated CFTR activity, leading to diminished Cl- and water secretion from airway epithelial cells and subsequent mucus plugging, which serves as the focus for infections. Females with CF exhibit reduced survival compared with males with CF, although the mechanisms underlying this sex-related disadvantage are unknown. Despite the lack of CFTR, CF airways retain a limited capability to regulate ASL volume, as breathing-induced ATP release activates salvage purinergic pathways that raise intracellular Ca2+ concentration to stimulate an alternate pathway to Cl- secretion. We hypothesized that estrogen might affect this pathway by reducing the ability of airway epithelia to respond appropriately to nucleotides. We found that uridine triphosphate-mediated (UTP-mediated) Cl- secretion was reduced during the periovulatory estrogen maxima in both women with CF and normal, healthy women. Estrogen also inhibited Ca2+ signaling and ASL volume homeostasis in non-CF and CF airway epithelia by attenuating Ca2+ influx. This inhibition of Ca2+ signaling was prevented and even potentiated by estrogen antagonists such as tamoxifen, suggesting that antiestrogens may be beneficial in the treatment of CF lung disease because they increase Cl- secretion in the airways.

Rho and ROCK signaling in VEGF-induced microvascular endothelial hyperpermeability.

OBJECTIVES: Vascular endothelial growth factor (VEGF) plays an important role in the regulation of microvascular permeability under various physiological and pathological conditions. The authors tested the hypothesis that the small GTPase Rho and its downstream effector ROCK (Rho-associated coiled-coil-containing protein kinase) mediate VEGF-induced increases in venular permeability. They also investigated myosin light chain (MLC) phosphorylation and actin polymerization, two well-characterized targets of the Rho-ROCK pathway that are implicated in the regulation of endothelial barrier function. METHODS: The apparent permeability coefficient of albumin (P(a)) was measured in intact isolated porcine coronary venules and in cultured coronary venular endothelial cell (CVEC) monolayers. RhoA activation was determined using a Rhotekin-agarose pull down assay. MLC phosphorylation was evaluated by immunoblotting with phospho-specific antibodies, and endothelial cellular F-actin was viewed using fluorescence microscopy. RESULTS: VEGF increased P(a) in both isolated coronary venules and CVEC monolayers. The hyperpermeability response occurred in a similar time course to that of Rho activation, MLC phosphorylation, and actin stress fiber formation. Selective blockage of ROCK with Y27632 dose-dependently inhibited VEGF-induced venular hyperpermeability. Moreover, inhibition of either Rho with exoenzyme C3 or ROCK with Y-27632 attenuated VEGF-induced increases in permeability, MLC phosphorylation, and actin-stress fiber formation in CVEC monolayers. CONCLUSIONS: Collectively, these findings suggest that the Rho-ROCK signal pathway contributes to VEGF-induced hyperpermeability. Myosin light-chain phosphorylation and actin stress fiber formation occur concomitantly with the increase in permeability upon VEGF stimulation.

Involvement of ROCK-mediated endothelial tension development in neutrophil-stimulated microvascular leakage.

Neutrophil-induced coronary microvascular barrier dysfunction is an important pathophysiological event in heart disease. Currently, the precise cellular and molecular mechanisms of neutrophil-induced microvascular leakage are not clear. The aim of this study was to test the hypothesis that rho kinase (ROCK) increases coronary venular permeability in association with elevated endothelial tension. We assessed permeability to albumin (P(a)) in isolated porcine coronary venules and in coronary venular endothelial cell (CVEC) monolayers. Endothelial barrier function was also evaluated by measuring transendothelial electrical resistance (TER) of CVEC monolayers. In parallel, we measured isometric tension of CVECs grown on collagen gels. Transference of constitutively active (ca)-ROCK protein into isolated coronary venules or CVEC monolayers caused a significant increase in P(a) and decreased TER in CVECs. The ROCK inhibitor Y-27632 blocked the ca-ROCK-induced changes. C5a-activated neutrophils (10(6)/ml) also significantly elevated venular P(a), which was dose-dependently inhibited by Y-27632 and a structurally distinct ROCK inhibitor, H-1152. In CVEC monolayers, activated neutrophils increased permeability with a concomitant elevation in isometric tension, both of which were inhibited by Y-27632 or H-1152. Treatment with ca-ROCK also significantly increased CVEC monolayer permeability and isometric tension, coupled with actin polymerization and elevated phosphorylation of myosin regulatory light chain on Thr18/Ser19. The data suggest that during neutrophil activation, ROCK promotes microvascular leakage in association with actin-myosin-mediated tension development in endothelial cells.

Identification of Raf-1 S471 as a novel phosphorylation site critical for Raf-1 and B-Raf kinase activities and for MEK binding.

The Ras-Raf-MAPK cascade is a key growth-signaling pathway and its uncontrolled activation results in cell transformation. Although the general features of the signal transmission along the cascade are reasonably defined, the mechanisms underlying Raf activation remain incompletely understood. Here, we show that Raf-1 dephosphorylation, primarily at epidermal growth factor (EGF)-induced sites, abolishes Raf-1 kinase activity. Using mass spectrometry, we identified five novel in vivo Raf-1 phosphorylation sites, one of which, S471, is located in subdomain VIB of Raf-1 kinase domain. Mutational analyses demonstrated that Raf-1 S471 is critical for Raf-1 kinase activity and for its interaction with mitogen-activated protein kinase kinase (MEK). Similarly, mutation of the corresponding B-Raf site, S578, resulted in an inactive kinase, suggesting that the same Raf-1 and B-Raf phosphorylation is needed for Raf kinase activation. Importantly, the naturally occurring, cancer-associated B-Raf activating mutation V599E suppressed the S578A mutation, suggesting that introducing a charged residue at this region eliminates the need for an activating phosphorylation. Our results demonstrate an essential role of specific EGF-induced Raf-1 phosphorylation sites in Raf-1 activation, identify Raf-1 S471 as a novel phosphorylation site critical for Raf-1 and B-Raf kinase activities, and point to the possibility that the V599E mutation activates B-Raf by mimicking a phosphorylation at the S578 site.