Effects of cladribine tablets on heart rate, atrio-ventricular conduction and cardiac repolarization in patients with relapsing multiple sclerosis.

AIMS: Cladribine tablets have shown significant efficacy for the treatment of relapsing multiple sclerosis, a chronic and debilitating immune-mediated disorder. This study was conducted to examine acute and/or cumulative effects of cladribine tablets 10 mg (3.5 or 5.25 mg/kg cumulative dose over 2 years) on heart rate, AV conduction and cardiac repolarization in patients with relapsing-remitting multiple sclerosis (RRMS). METHODS: CLARITY was a 96-week, double-blind, placebo-controlled, multicentre trial which evaluated the safety and efficacy of cladribine tablets 3.5 and 5.25 mg/kg body weight in patients with RRMS. A total of 135 patients were included in the ECG substudy, providing a total of 1534 post-dose ECGs. ECG data were collected 15 minutes pre-dose and between 0.5 and 3 hours post-dose at pre-study evaluation, study Day 1 and Weeks 5, 9, 13, 48 and 52. RESULTS: For cladribine tablets 3.5 mg/kg, the maximum change in placebo-adjusted post-dose QTcF vs. visit-baseline (BL) was -0.42 ms (90% CI: -3.61-4.44) at Week 1 (acute effects), and 3.20 ms (90% CI: -0.08-6.33) for cladribine tablets 5.25 mg/kg. The greatest observed differences in post-dose QTcF vs. study BL occurred at Week 48 for both the 3.5 and 5.25 mg/kg doses of cladribine tablets with 5.99 ms (90% CI: 0.53-11.44) and 8.74 ms (90% CI: 3.18-14.31), respectively. No significant changes were observed in T-wave morphology in either treatment group. CONCLUSIONS: Cladribine tablets 3.5 mg/kg (approved dose in Europe/other regions) did not confer clinically meaningful effects on heart rate, AV conduction and ventricular repolarization.

Effects of therapeutic and supratherapeutic doses of oral tedizolid phosphate on cardiac repolarisation in healthy volunteers: a randomised controlled study.

Drug-induced prolongation of the QT interval on the electrocardiogram (ECG) infrequently results in Torsades de pointes, a potentially fatal arrhythmia. Therefore, thorough QT analysis of new drugs is a regulatory requirement. The objective of this phase 1 study was to assess the effects of oral tedizolid phosphate on the QT interval corrected with Fridericia's formula (QTcF) in healthy adult subjects. A single therapeutic dose (200 mg) and a supratherapeutic dose (1200 mg) of tedizolid phosphate were administered to characterise QTc changes following typical systemic exposure and with markedly higher exposures, respectively. This was a four-way crossover study with 48 subjects randomly assigned to receive therapeutic and supratherapeutic doses of tedizolid phosphate, moxifloxacin (positive control for QT interval prolongation) and placebo (negative control). A continuous 12-lead ECG was recorded from 1 h before drug administration to 23 h after administration. Adverse events, which were generally mild, occurred most frequently with moxifloxacin or with a supratherapeutic dose of tedizolid phosphate; however, all treatments were well tolerated. This study demonstrated that therapeutic or supratherapeutic doses of the antibacterial tedizolid had no clinically significant effect on QT interval in healthy adults [ClinicalTrials.gov registration no.: NCT01461460].

Benefits of Centralized ECG Reading in Clinical Oncology Studies.

BACKGROUND: Many clinical trials of investigational oncologic agents utilize electrocardiogram (ECG) machine measurements of QTc, for inclusion/exclusion and dosing decisions, though their reliability in this setting has not been established. METHODS: We compared the digital ECG machine QTc measurements with those obtained by a centralized ECG core lab on more than 270,000 consecutive ECGs collected from 299 clinical oncology trials. RESULTS: The mean difference between the ECG machine measurements and the central measured QTcF was 1.8 ± 15.7 milliseconds. In addition, 29.7% of ECGs with an ECG machine-measured QTcF >450 milliseconds had a centrally measured QTcF <450 milliseconds, 44.6% of ECGs with an ECG machine-measured QTcF >470 milliseconds had a centrally measured QTcF <470 milliseconds, and 77.2% of ECGs with an ECG machine-measured QTcF >500 milliseconds had a centrally measured QTcF <500 milliseconds. The likelihood of a large discrepancy between the ECG machine- and centrally measured value for QTcF increased at both the high and low ends of the range of ECG machine QTcF measurements. CONCLUSIONS: While on average ECG machine-measured QTcF values were very similar to the central core lab measurements; there were very significant discrepancies which will have important implications for patient recruitment for clinical oncology trials as well as for patient safety during dosing with new oncologic agents. Reliance on ECG machine QTc measurements during clinical oncology trials may lead to unnecessary exclusion of patients as well as unneeded treatment interruptions.

A thorough QT study to evaluate the effects of therapeutic and supratherapeutic doses of delafloxacin on cardiac repolarization.

A randomized, double-blind, placebo-controlled, 4-period crossover study was conducted in 52 healthy adults to assess the effect of delafloxacin on the corrected QT (QTc) interval. The QT interval, corrected for heart rate using Fridericia's formula (QTcF), was determined predose and at 0.5, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 4, 5, 6, 12, 18, and 24 h after dosing with delafloxacin at 300 mg intravenously (i.v.; therapeutic), delafloxacin at 900 mg i.v. (supratherapeutic), moxifloxacin at 400 mg orally (p.o.; positive control), and placebo. The pharmacokinetic profile of delafloxacin was also evaluated. At each time point after delafloxacin administration, the upper limit of the 90% confidence interval (CI) for the placebo-corrected change from the predose baseline in QTcF (ΔΔQTcF) was less than 10 ms (maximum, 3.9 ms at 18 h after dosing), indicating an absence of a clinically meaningful increase in the QTc interval. The lower limit of the 90% CI of ΔΔQTcF for moxifloxacin versus placebo was longer than 5 ms at all 5 time points selected for assay sensitivity analysis, demonstrating that the study was adequately sensitive to assess QTc prolongation. There was no positive relationship between delafloxacin plasma concentrations and ΔΔQTcF. Treatment-emergent adverse events (AEs) were more frequent among subjects receiving a single supratherapeutic dose of 900 mg delafloxacin. There were no deaths, serious AEs, or AEs leading to study discontinuation and no clinically meaningful abnormalities in laboratory values or vital signs observed at any time point after any dose of the study drug.

Analysis of the potential effect of ponatinib on the QTc interval in patients with refractory hematological malignancies.

PURPOSE: Cardiac dysfunction, particularly QT interval prolongation, has been observed with tyrosine kinase inhibitors approved to treat chronic myeloid leukemia. This study examines the effects of ponatinib on cardiac repolarization in patients with refractory hematological malignancies enrolled in a phase 1 trial. METHODS: Electrocardiograms (ECGs) were collected at 3 dose levels (30, 45, and 60 mg) at 6 time points. Electrocardiographic parameters, including QTc interval, were measured, and 11 morphological analyses were conducted. Central tendency analyses of ECG parameters were performed using time-point and time-averaged approaches. All patients with at least 2 baseline ECGs and 1 on-treatment ECG were included in the analyses. Patients with paired ECGs and plasma samples were included in the pharmacokinetic/pharmacodynamic analysis to examine the relationship between ponatinib plasma concentration and change from baseline in QT intervals. RESULTS: Thirty-nine patients at the 30-, 45-, and 60-mg dose levels were included in the central tendency and morphological analyses. There was no significant effect on cardiac repolarization, as evidenced by non-clinically significant mean QTcF changes from baseline of -10.9, -3.6, and -5.0 ms for the 30-, 45-, and 60-mg dose levels, respectively. The morphological analysis revealed 2 patients with atrial fibrillation and 2 with T wave inversion. Seventy-five patients were included in the pharmacokinetic/pharmacodynamic analysis across all dose levels. The slope of the relationship for QTcF versus plasma ponatinib concentration was not positive (-0.0171), indicating no exposure-effect relationship. CONCLUSIONS: Ponatinib is associated with a low risk of QTc prolongation in patients with refractory hematological malignancies.

Evaluation of Eslicarbazepine acetate on cardiac repolarization in a thorough QT/QTc study.

This study investigated the effect of eslicarbazepine acetate (ESL) on cardiac repolarization in healthy adult volunteers. A randomized, placebo/active-controlled, 4-period crossover study was conducted in 67 participants. In 3 periods, participants received once-daily doses of ESL 1200 mg, ESL 2400 mg, and placebo for 5 days; in 1 period, participants received placebo on days 1 to 4 and a 400-mg moxifloxacin single dose on day 5. In each period, 24-hour 12-lead Holter monitoring was performed on days -;1 (baseline) and 5. There was no clinically relevant effect of ESL 1200 mg and 2400 mg versus placebo on cardiac depolarization or repolarization as measured by the QRS or QTc intervals, respectively. Mean PR interval increased following ESL 1200 mg and 2400 mg, but there was no participant with a PR interval above the upper limit of the normal range (200 ms). The upper bound of the 95% confidence interval for the placebo-corrected change from baseline of the individually corrected QT interval (QTcI) following administration of ESL 1200 mg and ESL 2400 mg was <10 ms at every time point. Moxifloxacin caused an increase in QTcI above the 10-ms threshold for clinical significance at several time points, demonstrating assay sensitivity. It is concluded that administration of ESL 1200 mg and ESL 2400 mg did not induce a clinically significant prolongation of the QTcI interval.

Electrocardiographic assessment for therapeutic proteins--scientific discussion.

Electrocardiographic monitoring is an integral component of the clinical assessment of cardiac safety of all compounds in development. The International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use E14 guideline recommends a dedicated study to evaluate drug-induced effects on cardiac repolarization ("thorough QT/QTc study"). There has been limited published information on QT interval changes secondary to therapeutic proteins; however, in theory, biologic therapies may affect cardiac electrical activity either directly or indirectly. This article summarizes scientific discussions of members of the Cardiac Safety Research Consortium and includes possible approaches to consider for the clinical evaluation of drug-induced QT prolongation in development programs of therapeutic proteins.

Absence of QTc prolongation in a thorough QT study with subcutaneous liraglutide, a once-daily human GLP-1 analog for treatment of type 2 diabetes.

The objective of this study was to establish effects of liraglutide on the QTc interval. In this randomized, placebo-controlled, double-blind crossover study, 51 healthy participants were administered placebo, 0.6, 1.2, and 1.8 mg liraglutide once daily for 7 days each. Electrocardiograms were recorded periodically over 24 hours at the end of placebo and highest dosing periods. Four different models for QT correction were used: QTci, as the primary endpoint, and QTciL, QTcF, and QTcB as secondary endpoints. The upper bound of the 1-sided 95% confidence interval for time-matched, baseline-corrected, placebo-subtracted QTc intervals was <10 ms for all 4 correction methods. Moxifloxacin (400 mg) increased QTc intervals by 10.6 to 12.3 ms at 2 hours. There was no concentration-exposure dependency on QTc interval changes by liraglutide and no QTc thresholds above 500 ms or QTc increases >60 ms. The authors conclude that liraglutide caused no clinically relevant increases in the QTc interval.

Drug-induced cardiac toxicity: emphasizing the role of electrocardiography in clinical research and drug development.

This review describes the role of electrocardiography in clinical research and drug development, and addresses its utility in defining cardiac toxicity from noncardiac investigational drugs. Principles for designing electrocardiographic monitoring for cardiac safety in clinical trials are also reviewed.