On Power and Sample Size Calculation for QT Studies with Recording Replicates at Given Time Point

Does Perioperative Use of Bisphosphonate Affect the Implant Revision Rate of Total Ankle Arthroplasty?

BACKGROUND

It is unknown whether perioperative bisphosphonate (BP) use reduces revision rates in total ankle replacement arthroplasty (TAR) although its effect has been demonstrated to be effective in reducing revision rates in total knee or hip replacement arthroplasty.

METHODS

We reviewed National Health Insurance Service data based on national health insurance service claims data and health care utilization, health screening, sociodemographic variables, medication history, operation codes, and mortality data for 50 million Koreans. From 2002 to 2014, 6391 of 7300 patients who underwent TAR were BP nonusers, whereas 909 patients were BP users. The revision rate according to BP medication and comorbidities was investigated. The Kaplan-Meier estimate and extended Cox proportional hazard model were also used.

RESULTS

The revision rate of TAR was 7.9% for BP users and 9.5% for BP nonusers, which showed no significant difference (P = .251). Implant survival over time decreased constantly. Adjusted hazard ratio for hypertension was 1.242 (P = .017), whereas other comorbidities such as diabetes had no effect on the revision rate of TAR.

CONCLUSION

We found that the perioperative BP use did not reduce the revision rate of TAR. Comorbidities (except hypertension) did not affect the revision rate of TAR. More research regarding various factors affecting the revision of TAR could be warranted.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Human olfactory mesenchymal stromal cell transplantation ameliorates experimental autoimmune encephalomyelitis revealing an inhibitory role for IL16 on myelination

One of the therapeutic approaches for the treatment of the autoimmune demyelinating disease, multiple sclerosis (MS) is bone marrow mesenchymal stromal cell (hBM-MSCs) transplantation. However, given their capacity to enhance myelination in vitro, we hypothesised that human olfactory mucosa-derived MSCs (hOM-MSCs) may possess additional properties suitable for CNS repair. Herein, we have examined the efficacy of hOM-MSCs versus hBM-MSCs using the experimental autoimmune encephalomyelitis (EAE) model. Both MSC types ameliorated disease, if delivered during the initial onset of symptomatic disease. Yet, only hOM-MSCs improved disease outcome if administered during established disease when animals had severe neurological deficits. Histological analysis of spinal cord lesions revealed hOM-MSC transplantation reduced blood–brain barrier disruption and inflammatory cell recruitment and enhanced axonal survival. At early time points post-hOM-MSC treatment, animals had reduced levels of circulating IL-16, which was reflected in both the ability of immune cells to secrete IL-16 and the level of IL-16 in spinal cord inflammatory lesions. Further in vitro investigation revealed an inhibitory role for IL-16 on oligodendrocyte differentiation and myelination. Moreover, the availability of bioactive IL-16 after demyelination was reduced in the presence of hOM-MSCs. Combined, our data suggests that human hOM-MSCs may have therapeutic benefit in the treatment of MS via an IL-16-mediated pathway, especially if administered during active demyelination and inflammation.

Enzyme-Linked Immunosorbent Assay Method Application in the Study of Comparative Pharmacokinetics of Insulin Glargin Preparations

Aims: adaptation and validation of the ELISA method insulin glargine determination for the pharmacokinetic study, practical approval in the biosimilars clinical trial.

Materials and methods. Serum insulin glargine determination was measured using a commercial ELISA kit. All tests were run on a Personal LAB machine (Adaltis S.r.l., Rome, Italy) with test systems for measuring the concentration of insulin glargine (Invitron Ltd., United Kingdom); human insulin concentrations were measured in the samples from the study for correction of cross-reactivity. Clinical part of this study included 42 male patients aged 18–65 with diabetes mellitus type 1. This was a double-blind, randomized, crossover clamp study with wash-out period of 7–14 days. Comparisons drugs: Insulin Glargine (glargine) solution for subcutaneous administration, 100 U/ml (GEROPHARM, Russia) and Lantus® (glargine) solution for subcutaneous administration, 100 U/ml (Sanofi-Aventis Deutschland GmbH, Germany).

Results. At the stage of the method adaptation the modification of original manufacturer’s method was performed; the full validation of modified analytical method for all parameters (selectivity, specificity, precision of calibration curves, intra- and inter-batch precision and accuracy, carry-over, dilution integrity, stability of solutions, stability in biologic matrix, parallelism) in accordance with regulatory authorities requirements has been done. The primary endpoint for long-acting insulins – AUCins.0-τ was calculated. Insulin Glargine and Lantus® are equivalent based on AUCins.0-τ data (point estimation for ratio of geometric means was 99 %, the confidence intervals for the ratio of the geometric mean for AUCins.0-τ was 81.02–120.62 %, that correspond to acceptance range 80.00–125.00 %).

Number of ECG Replicates and QT Correction Formula Influences the Estimated QT Prolonging Effect of a Drug

INTRODUCTION

The present analysis addressed the effect of the number of ECG replicates extracted from a continuous ECG on estimated QT interval prolongation for different QT correction formulas.

METHODS

For 100 healthy volunteers, who received a compound prolonging the QT interval, 18 ECG replicates within a 3-minute window were extracted from 12-lead Holter ECGs. Ten QT correction formulas were deployed, and the QTc interval was controlled for baseline and placebo and averaged per dose level.

RESULTS

The mean prolongation difference was >4 ms for single and >2 ms for triplicate ECG measurements compared with the 18 ECG replicate mean values. The difference was <0.5 ms after 14 replicates. By contrast, concentration-effect analysis was independent of replicate count and also of the QT correction formula.

CONCLUSION

The number of ECG replicates impacted the estimated QT interval prolongation for all deployed QT correction formulas. However, concentration-effect analysis was independent of both the replicate number and correction formula.

Human olfactory mesenchymal stromal cell transplants promote remyelination and earlier improvement in gait co-ordination after spinal cord injury

Autologous cell transplantation is a promising strategy for repair of the injured spinal cord. Here we have studied the repair potential of mesenchymal stromal cells isolated from the human olfactory mucosa after transplantation into a rodent model of incomplete spinal cord injury. Investigation of peripheral type remyelination at the injury site using immunocytochemistry for P0, showed a more extensive distribution in transplanted compared with control animals. In addition to the typical distribution in the dorsal columns (common to all animals), in transplanted animals only, P0 immunolabelling was consistently detected in white matter lateral and ventral to the injury site. Transplanted animals also showed reduced cavitation. Several functional outcome measures including end‐point electrophysiological testing of dorsal column conduction and weekly behavioural testing of BBB, weight bearing and pain, showed no difference between transplanted and control animals. However, gait analysis revealed an earlier recovery of co‐ordination between forelimb and hindlimb stepping in transplanted animals. This improvement in gait may be associated with the enhanced myelination in ventral and lateral white matter, where fibre tracts important for locomotion reside. Autologous transplantation of mesenchymal stromal cells from the olfactory mucosa may therefore be therapeutically beneficial in the treatment of spinal cord injury. GLIA 2017 GLIA 2017;65:639–656

Revisiting Milan cervical cancer study: Do the original findings hold in the era of chemotherapy?

BACKGROUND

The primary treatment of early stage cervical carcinoma (IB-IIA) is either surgery or radiation therapy based on the pivotal Milan randomized study published twenty years ago. In the presence of high-risk features, the gold standard treatment is concurrent chemotherapy and radiation therapy (CRT) whether it is the in the postoperative or the definitive setting. Using the National Cancer Data Base (NCDB), the goal of our study is to compare the outcomes of surgery and radiation therapy in the chemotherapy era.

METHODS

Between 2004 and 2013, 5478 patients diagnosed with early stage cervical cancer were divided into 2 groups based on their primary treatment: non-surgical (n=1980) and surgical groups (n=3498). The distribution of patient/tumor characteristics and treatment variables with their relation to overall survival and proportional regression models were assessed to investigate the superiority of one approach over the other. Propensity score analysis adjusted for imbalance of covariates to create a well-matched-patient cohort.

FINDINGS

At 46months median follow-up, the 5-year overall survival was similar between both groups (73·8% vs. 75.7%; p=0.619) after applying propensity score analysis. On multivariate analysis, high Charlson comorbidity score, stage IIA disease, larger tumor size, positive lymph nodes and high-grade disease were significant predictors of poor outcome while older age and treatment approach were not.

INTERPRETATION

Our analysis suggests that surgery (followed by adjuvant RT or CRT) and definitive radiotherapy (with or without chemotherapy) result in equivalent survival. Prospective studies are warranted to establish this paradigm in the chemotherapy era.

Timing of pre-dose baseline electrocardiograms in clinical trials: increased sampling over a prolonged baseline period worsens variance of QTc

BACKGROUND AND PURPOSE

The US Food and Drug Administration (US FDA) currently recommends recording of electrocardiograms (ECGs) prior to drug administration in thorough QT studies over an hour or more time to improve reliability of baseline ECG values. However, the baseline period is usually in the morning during a period of intense trial activity and rapid circadian change in QTc. The purpose of this study was to determine if the practice of recording an extended baseline does, in fact, decrease QTc variance at baseline.

METHODS

ECG data from three thorough QT studies (TQTS) in which three ECGs (commonly referred to as triplicates) were recorded at each of three pre-specified time points during the 60 to 90 minutes before drug administration were analyzed by determining the intra-subject and inter-subject standard deviation (SD) of QTcF (Fridericia-correct QT) for each of the three pre-drug time points and for the three time points combined.

RESULTS

QTcF was relatively normally distributed in each study. Intra-subject variability of QTcF was greater for the combined triplicate recordings than for the individual triplicates at baseline treatment time points in 39 of 42 cases (93%). This was the case in 48% of the comparisons in the inter-subject analysis.

CONCLUSIONS

The practice of recording three sets of triplicate ECGs over an hour or more before drug administration in a TQTS increases variability of baseline QTcF consistently in cross-over designed trials, and in roughly half of parallel comparisons. Higher variability suggests that the three-triplicate approach does not provide a more reliable baseline value. Less variability of QTcF can be obtained by simply recording one triplicate prior to drug administration. This principal may apply to other ECG and other physiological variables that have a monotonic circadian trend or that may be affected by intense trial activity during the pre-drug hour.

The joint modeling of drug and positive control effects to estimate sample size and power in crossover "thorough" QT/QTc studies

We present analytical results for computing the power and sample size in a thorough QT/QTc study with a four-period crossover design in which the treatments are placebo, positive control, supratherapeutic dose of investigational drug, and therapeutic dose of investigational drug. An assessment of noninferiority of the supratherapeutic dose to placebo is performed by the intersection-union test and assay sensitivity is tested (union-intersection test) at prespecified time points using positive control within the framework of a linear mixed-effects analysis. The power and sample size estimates are obtained using the joint distribution of statistics to test noninferiority of the supratherapeutic dose to placebo and to test assay sensitivity using positive control.

Sample size calculation for thorough QT/QTc study considering various factors related to multiple time points

The sample size requirement in a thorough QT/QTc study is discussed under a balanced parallel or crossover study design. First, we explore the impacts of various factors on the study power, including the mean effect profile across time and correlation among time points. Then we estimate the variability parameters needed based on multiple historical studies. Different baseline usage is illustrated to have a significant impact on the analysis variability in the parallel studies. Finally, the sample size calculations and recommendations are given for demonstrating a "negative" drug effect and the study assay sensitivity, respectively.

Quantitative analysis of T-wave morphology increases confidence in drug-induced cardiac repolarization abnormalities: evidence from the investigational IKr inhibitor Lu 35-138

This study investigates repolarization changes induced by a new candidate drug to determine whether a composite electrocardiographic (ECG) measure of T-wave morphology could be used as a reliable marker to support the evidence of abnormal repolarization, which is indicated by QT interval prolongation. Seventy-nine healthy subjects were included in this parallel study. After a baseline day during which no drug was given, 40 subjects received an I(Kr)-blocking antipsychotic compound (Lu 35-138) on 7 consecutive days while 39 subjects received placebo. Resting ECGs were recorded and used to determine a combined measure of repolarization morphology (morphology combination score [MCS]), based on asymmetry, flatness, and notching. Replicate measurements were used to determine reliable change and study power for both measures. Lu 35-138 increased the QTc interval with corresponding changes in T-wave morphology as determined by MCS. For subjects taking Lu 35-138, T-wave morphology was a more reliable indicator of I(Kr) inhibition than QTcF (chi(2) = 20.3, P = .001). At 80% study power for identifying a 5-millisecond placebo-adjusted change from baseline for QTcF, the corresponding study power for MCS was 93%. As a covariate to the assessment of QT interval liability, MCS offered important additive information to the effect of Lu 35-138 on cardiac repolarization.