Detection of QTc effects in small studies--implications for replacing the thorough QT study

A phase I thorough QT/QTc study evaluating therapeutic and supratherapeutic doses of avacopan in healthy participants

This phase I thorough QTc, double-blind, randomized, placebo- and positive-controlled, parallel group, multiple-dose study evaluated avacopan's effect on cardiac repolarization using concentration-QTc (C-QTc) as the primary analysis. Avacopan 30 mg b.i.d. (therapeutic dose) was administered orally on days 1 through 7 followed by avacopan 100 mg b.i.d. (supratherapeutic dose) on days 8 through 14 in 29 healthy participants. Moxifloxacin 400 mg and placebo were administered on days 1 and 15 in a nested crossover design for assay sensitivity in separate cohorts to 28 participants. Time-matched plasma concentrations and up to 10 replicate ECGs were obtained on prespecified days at baseline and postdose on days 1, 7, 14, and 15. The mean change from baseline on QTcF for avacopan (-5.5 to 3.5 ms) was similar to placebo (-6.9 to 1.4 ms) across days 1, 7, and 14. The mean effect on ΔΔQTcF (90% CI) was estimated as 1.5 ms (-0.17 to 3.09) and 0.8 ms (-2.41 to 4.05) for 30 and 100 mg avacopan b.i.d. treatments, respectively. Based on the C-QTc analysis, avacopan's effect on ΔΔQTcF >10 ms can be excluded within the observed plasma concentration range of up to ~1220 and ~335 ng/mL for avacopan and active major metabolite, M1, respectively. The estimated population slopes showed a shallow relationship, which was not statistically significant. There was no clinically meaningful effect of avacopan on heart rate or cardiac conduction (PR and QRS intervals). Avacopan appeared to be generally well tolerated in this study population.

No clinically relevant electrocardiogram effects in a randomized TQT study of single therapeutic/supratherapeutic rimegepant doses in healthy adults

A single-center, phase I, partially double-blind (double-blind regarding doses of rimegepant and placebo, and open label with respect to moxifloxacin), randomized, 12-sequence, four-period crossover study of therapeutic (75 mg) and supratherapeutic (300 mg) doses of rimegepant with placebo and moxifloxacin (400 mg) controls was designed to evaluate drug effect on the Fridericia corrected QT (QTcF) interval in healthy fasted adults. A total of 38 participants were randomized and dosed in the study. Electrocardiogram (ECG) data were available from 37 participants in the rimegepant 75-mg group, 38 participants in the rimegepant 300-mg group, and 36 participants in the moxifloxacin and placebo groups. Both the 75- and 300-mg doses of rimegepant had no clinically relevant effect on ECG parameters, including QTcF, heart rate, PR and QRS interval, T-wave morphology, and U-wave presence. All upper 90% confidence intervals for the QTcF effect with rimegepant were less than or equal to 4.69 ms, well below the 10-ms threshold for potential clinical significance. Assay sensitivity was demonstrated by the QT effect of moxifloxacin. Using both by-timepoint and concentration-QTc analysis, a placebo-corrected change-from-baseline QTcF greater than 10 ms could be excluded for rimegepant plasma concentrations up to ~10,000 ng/mL, representing concentrations at least 10.8-fold the maximum observed concentration of the 75-mg therapeutic dose of rimegepant.

Population pharmacokinetic/pharmacodynamic modeling of nifekalant injection with varies dosing plan in Chinese volunteers: a randomized, blind, placebo-controlled study

Nifekalant hydrochloride is a class III antiarrhythmic agent which could increase the duration of the action potential and the effective refractory period of ventricular and atrial myocytes by blocking the K+ current. Nifekalant is used to prevent ventricular tachycardia/ventricular fibrillation. QT interval prolongation is the main measurable drug effect. However, due to the complicated dosing plan in clinic, the relationship among dosage, time, drug concentration and efficacy is not fully understood. In this study, a single-center, randomized, blind, dose-ascending, placebo-controlled study was conducted to explore the intrinsic characteristics of nifekalant injection in healthy Chinese volunteers by a population pharmacokinetic (PK)-pharmacodynamic (PD) model approach. 42 subjects were enrolled in this study and received one of three dose plans (loading dose on Day 1 (0.15, 0.3 or 0.5 mg/kg), loading dose followed by maintenance dose (0.2, 0.4 or 0.8 mg/kg/h) on Day 4) or vehicle. Blood samples were drawn for PK evaluation, and ECGs were recorded for QTc calculation at the designed timepoints. No Torsades de Pointes occurred during the study. The popPK model of nifekalant injection could be described by a two-compartment model with first-order elimination. The population mean clearance (CL) was 53.8 L/h. The population mean distribution volume of the central (Vc) and peripheral (Vp) compartments was 8.27 L and 45.6 L, respectively. A nonlinear dose-response (Emax) model well described the pharmacodynamic effect (QTc interval prolongation) of nifekalant. The Emax and EC50 from current study were 101 ms and 342 ng/mL, respectively.

A comprehensive regulatory and industry review of modeling and simulation practices in oncology clinical drug development

Exposure-response (E-R) analyses are an integral component in the development of oncology products. Characterizing the relationship between drug exposure metrics and response allows the sponsor to use modeling and simulation to address both internal and external drug development questions (e.g., optimal dose, frequency of administration, dose adjustments for special populations). This white paper is the output of an industry-government collaboration among scientists with broad experience in E-R modeling as part of regulatory submissions. The goal of this white paper is to provide guidance on what the preferred methods for E-R analysis in oncology clinical drug development are and what metrics of exposure should be considered.

Evaluation of Deutetrabenazine's Potential to Delay Cardiac Repolarization Using Concentration-QTc Analysis

Deutetrabenazine (Austedo) is indicated in adults for chorea associated with Huntington disease and tardive dyskinesia. Escalating deutetrabenazine doses were administered to healthy volunteers who were cytochrome P450 2D6 extensive/intermediate metabolizers (EMs) or poor metabolizers (PMs) to determine pharmacokinetic exposure of parent drug and active metabolites (α-dihydrotetrabenazine [α-HTBZ] and β-dihydrotetrabenazine [β-HTBZ]), and collect corresponding electrocardiograms (ECGs) for evaluation of the cardiodynamic effect using concentration-QTc (C-QTc) modeling. Participants (12 EMs, 24 PMs) received placebo or single doses of deutetrabenazine (24, 48, and 72 mg) to achieve plasma concentrations exceeding therapeutic range in both cohorts. Pharmacokinetic samples were obtained over 72 hours after dosing and were time matched with 12-lead ECGs extracted from continuous ECG recordings. C-QTc analysis, using linear mixed-effects modeling and model selection procedure, characterized the relationship between plasma concentrations of deutetrabenazine, deuterated α-HTBZ and β-HTBZ, and the change from baseline in QT interval corrected using Fridericia's formula. Deutetrabenazine exhibited linear kinetics, and a C-QTc model with deuterated α-HTBZ and β-HTBZ was selected to best describe the C-QTc relationship in pooled EM and PM data. This model predicted a placebo-corrected Fridericia corrected QT interval prolongation higher than 10 milliseconds can be excluded at concentrations associated with the maximum recommended doses in both populations. Adverse events increased with higher exposure as reflected by the higher event number in the PM cohort receiving 48 and 72 mg doses. No subject discontinued due to cardiac-related adverse events and no clinically relevant ECG findings were reported. Thus, this study found that deutetrabenazine does not have a clinically relevant effect on QT prolongation at maximum recommended doses in either cytochrome P450 2D6 EMs or PMs.

A Phase 1 Thorough QT/QTc Study of Therapeutic and Supratherapeutic Doses of Belumosudil in Healthy Subjects

Belumosudil is a selective Rho-associated, coiled-coil-containing protein kinase-2 inhibitor. In this crossover design thorough QT/QTc study, single therapeutic (200 mg) and supratherapeutic (1000 mg) oral doses of belumosudil, moxifloxacin (positive control), and placebo were administered to 34 subjects. Twelve-lead electrocardiograms and serial pharmacokinetic sampling were acquired. The effect of belumosudil on the placebo-corrected, change-from-baseline QTcF was small, and an effect exceeding 10 ms could be excluded across all time points with both doses. Using concentration-QTc analysis, an effect on ΔΔQTcF >10 ms can be excluded up to belumosudil concentrations of ≈12 080 ng/mL, more than 2-fold above mean C_max after the supratherapeutic dose. There was no clinically relevant effect on heart rate or cardiac conduction (ie, the PR and QRS intervals) for belumosudil. No differences in safety were noted between belumosudil and placebo treatment. Assay sensitivity was demonstrated by moxifloxacin's effect on the QTc interval. In conclusion, belumosudil at therapeutic and supratherapeutic doses did not have a clinically meaningful effect on electrocardiogram parameters.

E2027 Cardiac Safety Evaluation With Concentration-Response Modeling of ECG Data to Inform Dose Selection in Studies in Patients With Dementia With Lewy Bodies

BACKGROUND

E2027 is a novel, highly selective and potent inhibitor of phosphodiesterase 9 in development for dementia with Lewy bodies. Cardiac safety assessments for emerging agents are essential to avoid drug-induced QT interval prolongation, which may predispose individuals to potentially fatal ventricular arrhythmias. To evaluate the cardiac safety of E2027 and to inform dose selection for the phase 2 study of E2027 in dementia with Lewy bodies, we evaluated concentration-response modeling of pooled electrocardiogram data.

PATIENTS AND METHODS

A post hoc concentration-QTc analysis evaluated potential QT effects using data from 2 randomized, double-blind studies in healthy subjects: a single ascending dose (SAD) study and a multiple ascending dose (MAD) study. Daily E2027 doses ranged from 5 to 1200 mg.

RESULTS

A linear mixed-effects model was used to establish the relationship between plasma concentrations of E2027 and change from the baseline of QTcF (ΔQTcF). A significant but shallow relationship was observed in the estimated slope of the concentration-ΔQTcF: 0.002 ms/ng/mL (90% confidence interval: 0.0007-0.0031) with a small, nonsignificant treatment effect-specific intercept of -0.6 ms. Based on this pooled concentration-QTc analysis, an effect on the QTcF interval >10 ms can be excluded up to E2027 plasma concentrations of ∼3579 ng/mL, corresponding to a dose at least 4-fold larger than the 50 mg phase 2 dose.

CONCLUSION

This pooled post hoc analysis evaluating cardiac safety of E2027 demonstrated that clinically concerning QTcF prolongation and related cardiac complications are highly unlikely with proposed E2027 doses planned for phase 2.

Concentration-QTc analysis with two or more correlated baselines

The relationship between drug concentration and QTc interval is typically evaluated by applying the standard analysis model proposed in a scientific whitepaper by Garnett et al. ( https://doi.org/10.1007/s10928-017-9558-5 ). The model is a mixed effects model in which a baseline QTc interval is included as a covariate. Two or more baseline QTc intervals are sometimes observed for a study participant, such as time-matched baselines on a baseline day in parallel studies, or pre-dose baselines in each period in crossover studies. In such situations, the baseline adjustments are not straightforward because these baselines correlate with not only the corresponding QTc intervals after drug administration, but also other QTc intervals at different timepoints for parallel studies, or those in different periods for crossover studies. In this study, we compared three analysis models through simulations and clinical study examples in settings in which two or more baselines were observed for a subject. We compared a model without baseline adjustment, a model with baseline adjustment, and a model in which baseline and baseline mean were included as covariates. In the simulations and clinical study examples, the model with baseline and baseline mean as covariates demonstrated higher accuracy and power than the other models. This model assumed a specific covariance structure in QTc intervals, which well approximated the correlations between QTc intervals within and between days. When there are two or more baselines in concentration-QTc analyses, the baseline mean should be included as a covariate in addition to the corresponding baseline.

QT Prolongation Risk Assessment in Oncology: Lessons Learned From Small-Molecule New Drug Applications Approved During 2011-2019

The International Conference on Harmonisation (ICH) E14 guidance provides recommendations to assess the potential of a drug to delay cardiac repolarization (QT prolongation), including general guidelines for cases in which a conventional thorough QT study (TQT) might not be feasible. These guidelines have been updated through the ICH question-and-answer process, with the last revision in 2015. We conducted a comprehensive analysis of QT prolongation evaluation of small-molecule new drug applications (NDAs) approved in oncology between 2011 and 2019 to extract learning experience. The following information was analysed: (1) methods to assess QT prolongation, (2) electrocardiogram data collection, (3) QT-related label language, and (4) postmarketing requirements. Overall, every NDA included a QT assessment. The concentration-QTc modeling approach (studies in which QT was not the primary objective) was the most common approach (59%), followed by the TQT and the dedicated QT studies (20% and 21%, respectively). The quality and quantity of the QT assessments were different across NDAs, which suggested relatively large flexibility in the designs and approaches to characterizing QT liability. The QT-related label language reflected the QT results, but also the safety events and the study design limitations because of the oncology settings. There was no delay in approval because of less robust QTc studies as long as the benefit-to-risk ratio of the drug was acceptable, and the implications were reflected in the label. This work offers a structured understanding of the QT evaluation criteria by the Food and Drug Administration and can assist in planning QT prolongation assessments in oncology settings.

Concentration-QTc analysis for single arm studies

Concentration-QTc (C-QTc) modeling is being increasingly used in phase 1 studies. For studies without a placebo arm (single arm studies), the scientific whitepaper by Garnett et al. ( https://doi.org/10.1007/s10928-017-9558-5 ) states that time-matched baseline adjustments may minimize the effect of diurnal variation in QTc intervals, and categorical time effects are not needed in the model. However, how diurnal variations can be accounted for when only pre-dose baselines are available is unclear. This research investigates whether including categorical time effects in the model can adjust diurnal variation in single arm studies with pre-dose baselines, where QTc prolongation is evaluated at a concentration of interest based on ΔQTc at 24 h and ΔΔQTc (a model-derived difference in ΔQTc from concentration zero). To understand the operating characteristics for the models with and without categorical time effects, simulations were conducted under various scenarios considering oncology early phase studies. When the C-QTc relationship is linear, models without categorical time effects provided biased estimates for model parameters and inflated or decreased false negative rates (FNRs) depending on the pattern of diurnal variations in QTc intervals, whereas models with categorical time effects caused no biases and controlled the FNRs. For non-linear C-QTc relationships, ΔΔQTc estimations made using the model with categorical time effects were not robust. Thus, for single arm studies where only pre-dose baselines are available, we recommend collecting QTc measurements at 24 h and estimating ΔQTc at a concentration of interest at 24 h using the C-QTc model with categorical time effects.

Novel concentration-QTc models for early clinical studies with parallel placebo controls: A simulation study

The QTc interval of the electrocardiogram is a pharmacodynamic biomarker for drug-induced cardiac toxicity. The ICH E14 guideline Questions and Answers offer a solution for evaluating a concentration-QTc relationship in early clinical studies as an alternative to conducting a thorough QT/QTc study. We focused on covariance structures of QTc intervals on the baseline day and dosing day (two-day covariance structure,) and proposed a two-day QTc model to analyze a concentration-QTc relationship for placebo-controlled parallel phase 1 single ascending dose studies. The proposed two-day QTc model is based on a constrained longitudinal data analysis model and a mixed effects model, thus allowing various variance components to capture the two-day covariance structure. We also propose a one-day QTc model for the situation where no baseline day or only a pre-dose baseline is available and models for multiple ascending dose studies where concentration and QTc intervals are available over multiple days. A simulation study shows that the proposed models control the false negative rate for positive drugs and have both higher accuracy and power for negative drugs than existing models in a variety of settings for the two-day covariance structure. The proposed models will promote early and accurate evaluation of the cardiac safety of new drugs.

The effect of the glucosylceramide synthase inhibitor lucerastat on cardiac repolarization: results from a thorough QT study in healthy subjects

BACKGROUND

Fabry disease is a rare inherited glycosphingolipid storage disorder caused by deleterious mutations in the GLA gene coding for the lysosomal enzyme α-galactosidase A. The glucosylceramide synthase inhibitor lucerastat is an iminosugar with potential to provide oral substrate reduction therapy in Fabry disease, regardless of the patient´s underlying mutation. Since lucerastat exhibits systemic exposure and many patients with Fabry disease suffer from rhythm and conduction abnormalities its effects on cardiac repolarization were evaluated in a thorough QT study.

METHODS

In Part A of this randomized, double-blind, placebo-controlled phase 1 study, single oral doses of 2000 and 4000 mg lucerastat were investigated to determine the supratherapeutic dose for Part B. The latter was a four-way crossover study to demonstrate that lucerastat at single oral therapeutic and supratherapeutic doses had no effect on the QTc interval > 10 ms using concentration-QTc modeling as primary analysis. The primary ECG endpoint was placebo-corrected change-from-baseline (ΔΔ) in Fridericia-corrected QTc (ΔΔQTcF). Open-label moxifloxacin served as positive control.

RESULTS

The effect of lucerastat on ΔΔQTcF was predicted as 0.39 ms (90% confidence interval [CI] - 0.13 to 0.90) and 1.69 ms (90% CI 0.33-3.05) at lucerastat peak plasma concentration after dosing with 1000 mg (5.2 µg/mL) and 4000 mg (24.3 µg/mL), respectively. A QTcF effect > 10 ms was excluded up to lucerastat plasma concentrations of approximately 34.0 µg/mL. Lucerastat did not exert an effect on other ECG parameters. Across doses, absorption of lucerastat was rapid, its elimination half-life ranged from 8.0 to 10.0 h, and the pharmacokinetics (PK) of lucerastat were dose-proportional. Moxifloxacin PK were in line with published data and assay sensitivity was demonstrated by the moxifloxacin QTc response. Lucerastat was safe and well tolerated.

CONCLUSIONS

Lucerastat up to a dose of 4000 mg has no clinically relevant liability to prolong the QT interval or any clinically relevant effect on other ECG parameters. This will be an important factor in the overall benefit-risk assessment of lucerastat in the potential treatment of Fabry disease. Trial registration The study was registered with the ClinicalTrials.gov identifier NCT03832452 (February 6th, 2019, https://clinicaltrials.gov/ct2/show/NCT03832452 ) and the EudraCT number 2018-004546-42 (December 17th, 2018).

Safety, Tolerability, Pharmacokinetics, and Concentration-QTc Analysis of Tetrodotoxin: A Randomized, Dose Escalation Study in Healthy Adults

Tetrodotoxin (TTX) is a highly specific voltage-gated sodium channel (VGSC) blocker in clinical evaluation as a peripheral-acting analgesic for chronic pain. This study presents the first published results of the safety including cardiac liability of TTX at therapeutic-relevant concentrations in twenty-five healthy adults. Randomized, double-blind, placebo-, and positive- (moxifloxacin) controlled study evaluated single ascending doses of 15 µg, 30 µg, and 45 µg TTX over 3 periods with a 7-day washout between each period. Subcutaneous injections of TTX were readily absorbed, reaching maximum plasma concentration (C_max) within 1.5 h. Both extent of exposure (AUC) and C_max increased in proportion to dose. No QT prolongation was identified by concentration-QTc analysis and the upper bounds of the two-sided 90% confidence interval of predicted maximum baseline and placebo corrected QTcF (ΔΔQTcF) value did not exceed 10 ms for all tetrodotoxin doses, thereby meeting the criteria of a negative QT study. Safety assessments showed no clinically relevant changes with values similar between all groups and no subject withdrawing due to adverse events. Paresthesia, oral-paresthesia, headache, dizziness, nausea, and myalgia were the most common TEAEs (overall occurrence ≥5%) in the TTX treatment groups. TTX doses investigated in this study are safe, well-tolerated, and lack proarrhythmic proclivity.

No QTc Prolongation With Zanubrutinib: Results of Concentration-QTc Analysis From a Thorough QT Study in Healthy Subjects

This thorough QT (TQT) study evaluated the effect of zanubrutinib on electrocardiogram (ECG) parameters by using concentration‐QTc (C‐QTc) analysis as the primary analysis for this study. Part A of the study determined the safety and tolerability of a single supratherapeutic dose of zanubrutinib (480 mg) in healthy volunteers. Part B was a randomized, blinded, placebo‐controlled and positive‐controlled, four‐way crossover, TQT study of single therapeutic (160 mg) and supratherapeutic (480 mg) doses of zanubrutinib, placebo, and open‐label moxifloxacin 400 mg. Thirty‐two participants received at least 1 dose of zanubrutinib, and 26 participants completed all 4 periods. Zanubrutinib did not have any effect on heart rate or cardiac conduction (pulse rate, QRS interval, or T‐wave morphology) and was generally well‐tolerated. Using C‐QTc analysis, the predicted placebo‐corrected change‐from‐baseline QT interval using Fridericia’s formula (ΔΔQTcF) was −3.4 msec (90% confidence interval: −4.9 to −1.9 msec) at peak concentrations of the 480 mg dose. A QT effect (ΔΔQTcF) exceeding 10 msec could be excluded within the observed concentration range at 160 and 480 mg doses. Assay sensitivity was established by moxifloxacin with 90% lower bound exceeding 5 msec. Implementing a C‐QTc analysis prospectively in this TQT study resulted in a substantially smaller sample size to maintain a similar study power as shown in the traditional time‐point analysis. A single 160‐mg or 480‐mg zanubrutinib dose did not prolong the QTc interval or have any other clinically relevant effects on ECG parameters.

Assessment of the effect of erdafitinib on cardiac safety: analysis of ECGs and exposure-QTc in patients with advanced or refractory solid tumors

PURPOSE

To characterize the effect of erdafitinib on electrocardiogram (ECG) parameters and the relationship between erdafitinib plasma concentrations and QTc interval changes in patients with advanced or refractory solid tumors.

METHODS

Triplicate ECGs and continuous 12-lead Holter data were collected in the dose escalation part (Part 1) of the first-in-human study, with doses ranging from 0.5 to 12 mg. Triplicate ECG monitoring continued in Parts 2-4 where 2 dose regimens selected from Part 1 were expanded in prespecified tumor types. Analyses of ECG data included central tendency analyses, identification of categorical outliers and morphological assessment. A concentration-QTc analysis was conducted using a linear mixed-effect model based on extracted time matching Holter data.

RESULTS

Central tendency, categorical outlier, and ECG morphologic analyses from 187 patients revealed no clinically significant effect of erdafitinib on heart rate, atrioventricular conduction or cardiac depolarization (PR and QRS), and no effect on cardiac repolarization (QTc). Concentration-QTc analysis from 62 patients indicated that the slopes of relationship between total and free erdafitinib plasma concentrations and QTcI (mean exponent of 0.395) were estimated as - 0.00269 ms/(ng/mL) and - 1.138 ms/(ng/mL), respectively. The predicted change in QTcI at the observed geometric mean of total and free concentration at the highest therapeutic erdafitinib dose (9 mg daily) was < 10 ms at the upper bound of the two-sided 90% confidence interval.

CONCLUSIONS

ECG data and the concentration-QTc relationships demonstrate that erdafitinib does not prolong QTc interval and has no effects on cardiac repolarization or other ECG parameters. Clinical trial registration numbers NCT01703481, EudraCT: 2012-000697-34.

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.

Assessment of Multi-Ion Channel Block in a Phase I Randomized Study Design: Results of the CiPA Phase I ECG Biomarker Validation Study

Balanced multi‐ion channel‐blocking drugs have low torsade risk because they block inward currents. The Comprehensive In Vitro Proarrhythmia Assay (CiPA) initiative proposes to use an in silico cardiomyocyte model to determine the presence of balanced block, and absence of heart rate corrected J‐T_peak (J‐T_peakc) prolongation would be expected for balanced blockers. This study included three balanced blockers in a 10‐subject‐per‐drug parallel design; lopinavir/ritonavir and verapamil met the primary end point of ΔΔJ‐T_peakc upper bound < 10 ms, whereas ranolazine did not (upper bounds of 8.8, 6.1, and 12.0 ms, respectively). Chloroquine, a predominant blocker of the potassium channel encoded by the ether‐à‐go‐go related gene (hERG), prolonged ΔΔQTc and ΔΔJ‐T_peakc by ≥ 10 ms. In a separate crossover design, diltiazem (calcium block) did not shorten dofetilide‐induced ΔQTc prolongation, but shortened ΔJ‐T_peakc and prolonged ΔT_peak‐T_end. Absence of J‐T_peakc prolongation seems consistent with balanced block; however, small sample size (10 subjects) may be insufficient to characterize concentration‐response in some cases.

Evaluation of the Cardiac Safety of Long-Acting Endectocide Moxidectin in a Randomized Concentration-QT Study

Potential effects on cardiac repolarization of single doses of moxidectin, a potent long‐acting macrocyclic lactone endectocide, were assessed in a concentration‐QT (c‐QT; exposure‐response) study. This double‐blind, placebo‐controlled, parallel‐group study in healthy male volunteers (n = 60) randomized subjects to a single oral dose of moxidectin (4 mg, 8 mg, 16 mg, 24 mg, or 36 mg) or matching placebo. Serial plasma samples for pharmacokinetic (PK) analysis and concurrent triplicate electrocardiogram measurements were taken at baseline and 14 prespecified time points over 72 hours, yielding 900 QT interval‐plasma concentration time‐matched pairs. Moxidectin had no statistically significant or clinically relevant impact on QT interval at any dose level. The primary mixed effects model analysis revealed no treatment‐related impact on the Fridericia‐corrected QT interval‐plasma concentration gradient (−0.0077, 90% confidence interval (CI) −0.0255 to +0.0101).

Drug-induced Proarrhythmia and Torsade de Pointes: A Primer for Students and Practitioners of Medicine and Pharmacy

Multiple marketing withdrawals due to proarrhythmic concerns occurred in the United States, Canada, and the United Kingdom in the late 1980s to early 2000s. This primer reviews the clinical implications of a drug's identified proarrhythmic liability, the issues associated with these safety-related withdrawals, and the actions taken by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) and by regulatory agencies in terms of changing drug development practices and introducing new nonclinical and clinical tests to asses proarrhythmic liability. ICH Guidelines S7B and E14 were released in 2005. Since then, they have been adopted by many regional regulatory authorities and have guided nonclinical and clinical proarrhythmic cardiac safety assessments during drug development. While this regulatory paradigm has been successful in preventing drugs with unanticipated potential for inducing the rare but potentially fatal polymorphic ventricular arrhythmia torsade de pointes from entering the market, it has led to the termination of drug development programs for other potentially useful medicines because of isolated results from studies with limited predictive value. Research efforts are now exploring alternative approaches to better predict potential proarrhythmic liabilities. For example, in the domain of human electrocardiographic assessments, concentration-response modeling conducted during phase 1 clinical development has recently become an accepted alternate primary methodology to the ICH E14 "thorough QT/QTc" study for defining a drug's corrected QT interval prolongation liability under certain conditions. When a drug's therapeutic benefit is considered important at a public health level but there is also an identified proarrhythmic liability that may result from administration of the single drug in certain individuals and/or drug-drug interactions, marketing approval will be accompanied by appropriate directions in the drug's prescribing information. Health-care professionals in the fields of medicine and pharmacy need to consider the prescribing information in conjunction with individual patients' clinical characteristics and concomitant medications when prescribing and dispensing such drugs.

Evaluating cardiac risk: exposure response analysis in early clinical drug development

The assessment of a drug's cardiac liability has undergone considerable metamorphosis by regulators since International Council for Harmonization of Technical Requirement for Pharmaceuticals for Human Use E14 guideline was introduced in 2005. Drug developers now have a choice in how proarrhythmia risk can be evaluated; the options include a dedicated thorough QT (TQT) study or exposure response (ER) modeling of intensive electrocardiogram (ECG) captured in early clinical development. The alternative approach of ER modeling was incorporated into a guidance document in 2015 as a primary analysis tool which could be utilized in early phase dose escalation studies as an option to perform a dedicated TQT trial. This review will describe the current state of ER modeling of intensive ECG data collected during early clinical drug development; the requirements with regard to the use of a positive control; and address the challenges and opportunities of this alternative approach to assessing QT liability.

Evaluating Potential QT Effects of JNJ-54861911, a BACE Inhibitor in Single- and Multiple-Ascending Dose Studies, and a Thorough QT Trial With Additional Retrospective Confirmation, Using Concentration-QTc Analysis

Nonclinical assays with JNJ-54861911, a β-secretase 1 inhibitor have indicated that at high concentrations, it may delay cardiac repolarization. A 4-way crossover thorough QT (TQT) study was performed in 64 healthy subjects with 50 and 150 mg JNJ-54861911 once daily for 7 days, placebo, and 400 mg moxifloxacin. Retrospective high-precision QT (HPQT) analysis was performed on serial elecrocardiograms extracted from first-in-human single-ascending dose (SAD) and multiple-ascending dose (MAD) studies to evaluate if early studies could detect and predict QT effect. In the TQT study, a high therapeutic 50 mg dose did not cause QT prolongation, and an effect >10 milliseconds could be excluded at all postdose timepoints. QT prolongation with peak effect on placebo-corrected change from baseline QTcF of 15.5 milliseconds (90%CI, 12.9-18.1 milliseconds) was observed following a supratherapeutic dose (150 mg). No clinically relevant QT changes were observed in earlier studies. However, with SAD/MAD findings by HPQT, the slope of the exposure-response (ER) relationship in the SAD study (doses up to 150 mg) was similar to the TQT study slope, and the estimated QT effect was comparable at high plasma levels. In the MAD study, doses up to 90 mg once daily for 7 days resulted in JNJ-54861911 peak plasma concentrations (C_max ) comparable to those in the SAD study (∼750 ng/mL), but ER by HPQT failed to detect a QT effect and resulted in negative estimations. Adding a higher dose cohort (150 mg; C_max , 1125 ng/mL) demonstrated a QT effect, with a slightly lower ER slope than the TQT study. JNJ-54861911 (up to 50 mg) did not cause QT prolongation at clinically relevant plasma concentrations in any studies. Provided sufficiently high plasma concentrations were captured, mild QT prolongation observed postdose with a supratherapeutic dose could be detected (TQT study) and estimated in SAD/MAD studies. Based on population pharmacokinetic modeling and simulation, 5 and 25 mg doses are currently considered for further phase 3 studies and are expected not to cause any relevant QT prolongation.

Study Design Parameters Affecting Exposure Response Analysis of QT Data: Results From Simulation Studies

The operating characteristics of dose-escalating studies in terms of false-negative predictions of the QT effect and the power to exclude clinically relevant QT effects are not quantitatively established. One thousand single-ascending-dose (SAD) studies with 7 dose groups with 6/2 subjects on active drug/placebo were generated through simulation for each of 32 scenarios with (1) 8 different QT effects of the study drug and (2) achieved plasma concentration 2- or 4-fold above therapeutic levels. For each subject, drug-free QT data from a thorough QT study were subsampled to capture the circadian profile, on which a drug effect was added. The percentage of false-negative studies was between 4% and 9% when the drug's QT effect was set to 10 milliseconds. If a somewhat lower effect of 6.7 milliseconds was set at therapeutic concentrations, the fraction of negative studies was higher, 40% to 60% when the variability of the QT data was well controlled. When the QT effect was set to 5 milliseconds at therapeutic plasma concentrations, the power of SAD studies to exclude 10 milliseconds QT effect was generally above 70% (74% to 94%) with well-controlled QT variability, whereas the power was reduced to 36% to 69% if supratherapeutic plasma concentrations were not achieved. The rate of false-negative studies was acceptably low in placebo-controlled SAD studies. With a drug with no or a small QT effect, supratherapeutic plasma concentrations, and well-controlled variability of QT data, the power of SAD studies to exclude a relevant effect was above 70%.

Mechanistic Model-Informed Proarrhythmic Risk Assessment of Drugs: Review of the "CiPA" Initiative and Design of a Prospective Clinical Validation Study

The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is developing and validating a mechanistic-based assessment of the proarrhythmic risk of drugs. CiPA proposes to assess a drug's effect on multiple ion channels and integrate the effects in a computer model of the human cardiomyocyte to predict proarrhythmic risk. Unanticipated or missed effects will be assessed with human stem cell-derived cardiomyocytes and electrocardiogram (ECG) analysis in early phase I clinical trials. This article provides an overview of CiPA and the rationale and design of the CiPA phase I ECG validation clinical trial, which involves assessing an additional ECG biomarker (J-Tpeak) for QT prolonging drugs. If successful, CiPA will 1) create a pathway for drugs with hERG block / QT prolongation to advance without intensive ECG monitoring in phase III trials if they have low proarrhythmic risk; and 2) enable updating drug labels to be more informative about proarrhythmic risk, not just QT prolongation.

Mechanistic Model-Informed Proarrhythmic Risk Assessment of Drugs: Review of the "CiPA" Initiative and Design of a Prospective Clinical Validation Study

The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is developing and validating a mechanistic-based assessment of the proarrhythmic risk of drugs. CiPA proposes to assess a drug's effect on multiple ion channels and integrate the effects in a computer model of the human cardiomyocyte to predict proarrhythmic risk. Unanticipated or missed effects will be assessed with human stem cell-derived cardiomyocytes and electrocardiogram (ECG) analysis in early phase I clinical trials. This article provides an overview of CiPA and the rationale and design of the CiPA phase I ECG validation clinical trial, which involves assessing an additional ECG biomarker (J-Tpeak) for QT prolonging drugs. If successful, CiPA will 1) create a pathway for drugs with hERG block / QT prolongation to advance without intensive ECG monitoring in phase III trials if they have low proarrhythmic risk; and 2) enable updating drug labels to be more informative about proarrhythmic risk, not just QT prolongation.

Estimation of the Power of the Food Effect on QTc to Show Assay Sensitivity

The most recent International Conference on Harmonisation E14 Q&A document states that a separate positive control would not be necessary provided sufficiently high exposures are achieved in the early-phase studies. Realistically, a phase 1 study is unlikely to include a pharmacological positive control, and in cases in which plasma levels of the drug exceeding therapeutic levels are not achieved, the lack of a positive control can constitute a limitation when excluding an effect of regulatory concern. It has been proposed to use the effect of a standardized meal on the estimate of the diurnal time course of QTc to show assay sensitivity. We conducted simulations by subsampling subjects from a 3 different studies and could show that the effect on food on QTc can be reliably prove assay sensitivity for sample sizes as low as 3 × 6 subjects with a power greater than 80%.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

Estimation of QT interval prolongation through model-averaging

The current method to analyze concentration-QT interval data, which is based on predictions conditional on a best model, fails to take into account the uncertainty of the model. Previous studies have suggested that failure to take into account model uncertainty using a best model approach can result in confidence intervals that are overly optimistic and may be too narrow. Theoretically, more realistic estimates are obtained using model-averaging where the overall point estimate and confidence interval are a weighted-average from a set of candidate models, the weights of which are equal to each model's Akaike weight. Monte Carlo simulation was used to determine the degree of narrowness in the confidence interval for the degree of QT prolongation under a single ascending dose and thorough QT trial design. Results showed that model averaging performed as well as the best model approach under most conditions with no numeric advantage to using a model averaging approach. No difference was observed in the coverage of the confidence intervals when the best model and model averaging was done by AIC, AICc, or BIC, although in certain circumstances the coverage of the confidence interval themselves tended to be too narrow when using BIC. Modelers can continue to use the best model approach for concentration-QT modeling with confidence, although model averaging may offer more face validity, may be of value in cases where there is uncertainty or misspecification in the best model, and be more palatable to a non-technical reviewer than the best model approach.

Comparing QT interval variability of semiautomated and high-precision ECG methodologies in seven thorough QT studies-implications for the power of studies intended for definitive evaluation of a drug's QT effect

BACKGROUND

In studies of drug effects on electrocardiographic parameters, the level of precision in measuring QTc interval changes will influence a study's ability to detect small effects.

METHODS

Variability data from investigational, placebo and moxifloxacin treatments from seven thorough QT studies performed by the same sponsor were analyzed with the objective to compare the performance of two commonly used approaches for ECG interval measurements: semiautomated (SA) and the high-precision QT (HPQT) analysis. Five studies were crossover and two parallel. Harmonized procedures were implemented to ensure similar experimental conditions across studies. ECG replicates were extracted serially from continuous 12-lead recordings at predefined time points from subjects supinely resting. The variability estimates were based on the time-point analysis of change-from-baseline QTcF as the dependent variable for the standard primary analysis of previous thorough QT studies. The residual variances were extracted for each study and ECG technique.

RESULTS

High-precision QT resulted in a substantial reduction in ∆QTc variability as compared to SA. A reduction in residual variability or approximately 50% was achieved in both crossover and parallel studies, both for the active comparison (drug vs. placebo) and for assay sensitivity (moxifloxacin vs. placebo) data.

CONCLUSIONS

High-precision QT technique significantly reduces QT interval variability and thereby the number of subjects needed to exclude small effects in QT studies. Based on this assessment, the sample size required to exclude a QTc effect >10 ms with 90% power is reduced from 35 with SA to 18 with HPQT, if a 3 ms underlying drug effect is assumed.

Detecting moxifloxacin-induced QTc prolongation in thorough QT and early clinical phase studies using a highly automated ECG analysis approach

BACKGROUND AND PURPOSE

Exposure-response (ER) modelling (concentration-QTc analysis) is gaining as much acceptance as the traditional by-time analysis of the placebo-adjusted change from baseline in the QTc interval (ΔΔQTcF). It has been postulated that intensive ECG analysis and ER modelling during early-phase drug development could be a cost-effective approach of estimating QT liability of a new drug, in a small number of subjects.

EXPERIMENTAL APPROACH

We used a highly automated analysis of ECGs from 46 subjects from a crossover thorough QT/QTc study to detect ΔΔQTcF with moxifloxacin. Using these data, we also simulated (bootstrapped) 1000 datasets of a parallel study with eight subjects receiving moxifloxacin and eight others receiving placebo.

KEY RESULTS

The slope from the concentration-QTc analysis for moxifloxacin in 46 subjects was 4.12 ms of ΔΔQTcF per μg(-1) mL(-1) ; at mean Cmax of 2.95 μg·mL(-1) , estimated ΔΔQTcF was 13.4 ms (90% confidence interval 11.3, 15.4 ms). In the 1000 simulated datasets, in 996 datasets, ER modelling showed that the upper bound of the 90% confidence interval for ΔΔQTcF at geometric mean Cmax exceeded 10 ms. In 895 of these 996 datasets, the slope of the ER relationship was statistically significantly positive. Thus, with a small sample size (eight subjects on active drug and eight on placebo), moxifloxacin-induced QTc prolongation was demonstrated using ER analysis with statistical power of >80%.

CONCLUSIONS AND IMPLICATIONS

Our study adds to the growing body of data supporting intensive ECG collection and analysis in early-phase studies to estimate QT liability.

Can an early phase clinical pharmacology study replace a thorough QT study? Experience with a novel H3-receptor antagonist/inverse agonist

OBJECTIVE

The objective of the present study was to compare the effects of pitolisant on QTcF interval in a single ascending dose (SAD) study and a thorough QT (TQT) study.

METHODS

The SAD study at three dose levels of pitolisant enrolled 24 males and the TQT study at two dose levels 25 males. Both studies intensively monitored ECGs and pitolisant exposure. Effect on QTcF interval was analysed by Intersection Union Test (IUT) and by exposure-response (ER) analysis. Results from the two studies were compared.

RESULTS

In both studies, moxifloxacin effect established assay sensitivity. IUT analysis revealed comparable pitolisant-induced maximum mean (90 % confidence interval (CI)) placebo-corrected increase from baseline (ΔΔQTcF) in both the studies, being 13.3 (8.1; 18.5) ms at 200-mg and 9.9 (4.7; 15.1) ms at 240-mg doses in SAD study and 5.27 (2.35; 8.20) ms at 120-mg dose in TQT study. ER analysis revealed that ER slopes in SAD and TQT studies were comparable and significantly positive (0.031 vs 0.027 ms/ng/mL, respectively). At geometric mean concentrations, bootstrap predicted ΔΔQTcF (90 % CI) were 9.23 (4.68; 14.4) ms at 279 ng/mL (240-mg dose) in the SAD study and 4.97 (3.42; 8.19) ms at 156 ng/mL (120-mg dose) in the TQT study.

CONCLUSION

Pitolisant lacked an effect of regulatory concern on QTc interval in both the studies, however analysed, suggesting that the results from the SAD study could have mitigated the need for a TQT study. Our findings add to the growing evidence that intensive ECG monitoring in early phase clinical studies can replace a TQT study.

No Untoward Effect of Long-Term Ketoconazole Administration on Electrocardiographic QT Interval in Patients with Cushing's Disease

Ketoconazole is listed among drugs that prolong QT interval and may increase the risk of torsade de pointes, a severe ventricular arrhythmia. This compound has recently been approved for treatment of Cushing's syndrome, a severe endocrine disorder. These patients harbour several risk factors for prolonged QT interval, for example hypokalaemia and left ventricular hypertrophy, but no study has evaluated whether administration of ketoconazole affects their QT interval. The aim of this study was to assess the QT interval in patients with Cushing's disease during long-term administration of ketoconazole. Electrocardiograms from 15 patients with Cushing's disease (12 women, 3 men, age: 37.8 ± 2.66 years) on ketoconazole treatment (100 mg-800 mg qd) for 1 month to 12 years were reviewed retrospectively. QT interval was measured and corrected for heart rate (QTc). Measurements before and during ketoconazole treatment were compared and any abnormal QTc value recorded. Concurrent medical therapies were also documented. On average, QTc was superimposable before and during ketoconazole treatment (393.2 ± 7.17 versus 403.3 ± 6.05 msec. in women; 424.3 ± 23.54 versus 398.0 ± 14.93 msec. in men, N.S.). QTc normalized on ketoconazole in one man with prolonged QTc prior to treatment; no abnormal QTc was observed in any other patient during the entire observation period, even during concurrent treatment with other QT-prolonging drugs. In conclusion, long-term ketoconazole administration does not appear to be associated with significant prolongation of QT interval in patients with Cushing's disease. ECG monitoring can follow recommendations drawn for other low-risk QT-prolonging drugs with attention to specific risk factors, for example hypokalaemia and drug interactions.

The Power of Phase I Studies to Detect Clinical Relevant QTc Prolongation: A Resampling Simulation Study

Concentration-effect (CE) models applied to early clinical QT data from healthy subjects are described in the latest E14 Q&A document as promising analysis to characterise QTc prolongation. The challenges faced if one attempts to replace a TQT study by thorough ECG assessments in Phase I based on CE models are the assurance to obtain sufficient power and the establishment of a substitute for the positive control to show assay sensitivity providing protection against false negatives. To demonstrate that CE models in small studies can reliably predict the absence of an effect on QTc, we investigated the role of some key design features in the power of the analysis. Specifically, the form of the CE model, inclusion of subjects on placebo, and sparse sampling on the performance and power of this analysis were investigated. In this study, the simulations conducted by subsampling subjects from 3 different TQT studies showed that CE model with a treatment effect can be used to exclude small QTc effects. The number of placebo subjects was also shown to increase the power to detect an inactive drug preventing false positives while an effect can be underestimated if time points around t_max are missed.

Evaluation of the QT effect of a combination of piperaquine and a novel anti-malarial drug candidate OZ439, for the treatment of uncomplicated malaria

AIMS

The aim was to investigate the QT effect of a single dose combination regimen of piperaquine phosphate (PQP) and a novel aromatic trioxolane, OZ439, for malaria treatment.

METHODS

Exposure-response (ER) analysis was performed on data from a placebo-controlled, single dose, study with OZ439 and PQP. Fifty-nine healthy subjects aged 18 to 55 years received OZ439 alone or placebo in a first period, followed by OZ439 plus PQP or matching placebos in period 2. OZ439 and PQP doses ranged from 100-800 mg and 160-1440 mg, respectively. Twelve-lead ECG tracings and PK samples were collected serially pre- and post-dosing.

RESULTS

A significant relation between plasma concentrations and placebo-corrected change from baseline QTc F (ΔΔQTc F) was demonstrated for piperaquine, but not for OZ439, with a mean slope of 0.047 ms per ng ml(-1) (90% CI 0.038, 0.057). Using an ER model that accounts for plasma concentrations of both piperaquine and OZ439, a largest mean QTc F effect of 14 ms (90% CI 10, 18 ms) and 18 ms (90% CI 14, 22 ms) was predicted at expected plasma concentrations of a single dose 800 mg OZ439 combined with PQP 960 mg (188 ng ml(-1) ) and 1440 mg (281 ng ml(-1) ), respectively, administered in the fasted state.

CONCLUSIONS

Piperaquine prolongs the QTc interval in a concentration-dependent way. A single dose regimen combining 800 mg OZ439 with 960 mg or 1440 mg PQP is expected to result in lower peak piperaquine plasma concentrations compared with available 3 day PQP-artemisinin combinations and can therefore be predicted to cause less QTc prolongation.

Results from the IQ-CSRC prospective study support replacement of the thorough QT study by QT assessment in the early clinical phase

The QT effects of five "QT-positive" and one negative drug were tested to evaluate whether exposure-response analysis can detect QT effects in a small study with healthy subjects. Each drug was given to nine subjects (six for placebo) in two dose levels; positive drugs were chosen to cause 10 to 12 ms and 15 to 20 ms QTcF prolongation. The slope of the concentration/ΔQTc effect was significantly positive for ondansetron, quinine, dolasetron, moxifloxacin, and dofetilide. For the lower dose, an effect above 10 ms could not be excluded, i.e., the upper bound of the confidence interval for the predicted mean ΔΔQTcF effect was above 10 ms. For the negative drug, levocetirizine, a ΔΔQTcF effect above 10 ms was excluded at 6-fold the therapeutic dose. The study provides evidence that robust QT assessment in early-phase clinical studies can replace the thorough QT study.