Borje Darpo

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.

The IQ‐CSRC Prospective Clinical Phase 1 Study: “Can Early QT Assessment Using Exposure Response Analysis Replace the Thorough QT Study?”

A collaboration between the Consortium for Innovation and Quality in Pharmaceutical Development and the Cardiac Safety Research Consortium has been formed to design a clinical study in healthy subjects demonstrating that the thorough QT (TQT) study can be replaced by robust ECG monitoring and exposure–response (ER) analysis of data generated from First‐in‐Man single ascending dose (SAD) studies. Six marketed drugs with well‐characterized QTc effects were identified in discussions with FDA; five have caused QT prolongation above the threshold of regulatory concern. Twenty healthy subjects will be enrolled in a randomized, placebo‐controlled study designed with the intent to have similar power to exclude small QTc effects as a SAD study. Two doses (low and high) of each drug will be given on separate, consecutive days to 9 subjects. Six subjects will receive placebo. Data will be analyzed using linear mixed‐effects ER models. Criteria for QT‐positive drugs will be the demonstration of an upper bound (UB) of the 2‑sided 90% confidence interval (CI) of the projected QTc effect at the peak plasma level of the lower dose above the threshold of regulatory concern (currently 10 ms) and a positive slope of ER relationship. The criterion for QT‐negative drug will be an UB of the CI of the projected QTc effect of the higher dose <10 ms. It is expected that a successful outcome in this study will provide evidence supporting replacement of the TQT study with ECG assessments in standard early clinical development studies for a new chemical entity.

Methodologies to characterize the QT/corrected QT interval in the presence of drug-induced heart rate changes or other autonomic effects

This White Paper, written collaboratively by members of the Cardiac Safety Research Consortium from academia, industry, and regulatory agencies, discusses different methods to characterize the QT effects for drugs that have a substantial direct or indirect effect on heart rate. Descriptions and applications are provided for individualized QT-R-R correction, Holter bin, dynamic QT beat-to-beat, pharmacokinetic-pharmacodynamic modeling, and QT assessment at constant heart rate. Most of these techniques are optimally performed using continuous electrocardiogram data obtained in clinical studies designed to characterize a drugs effect on the QT interval. An important study design element is the collection of drug-free data over a range of heart rates seen on treatment. The range of heart rates is increased at baseline by using ambulatory electrocardiogram recordings in addition to those collected under semisupine, resting conditions. Discussions in this study summarize areas of emerging consensus and other areas in which consensus remains elusive and provide suggestions for additional research to further increase our knowledge and understanding of this topic.

Early QT assessment – how can our confidence in the data be improved?

Exposure–response (ER) analysis has emerged as an important tool to interpret QT data from thorough QT (TQT) studies and allows the prediction of effects in the targeted patient population. Recently, ER analysis has also been applied to data from early clinical pharmacology studies, such as single and multiple ascending dose studies, in which high plasma concentrations are often achieved. In line with this, there is an on‐going discussion between sponsors, academicians and regulators on whether ‘early QT assessment’ can provide sufficiently high confidence in assessment of QT prolongation to replace the TQT study. In this article, we discuss how QT assessment can be applied to early clinical studies (‘early QT assessment’) and what we believe is needed to achieve the same high confidence in the data as we currently obtain from data from the TQT study. The power to exclude a QTc effect exceeding 10 ms in small sample sizes using ER analysis will be discussed and compared with time‐matched analysis, as described in the ICH E14 guidance. Two examples of early QT assessment are shared; one negative and one positive, and the challenge in terms of demonstrating assay sensitivity in the absence of a pharmacological positive control will be discussed. Finally, we describe a recent research proposal, which may generate data to support the replacement of the TQT study with data from QT assessment in early phase 1 studies.

Exenatide at therapeutic and supratherapeutic concentrations does not prolong the QTc interval in healthy subjects

Aims Exenatide has been demonstrated to improve glycaemic control in patients with type 2 diabetes, with no effect on heart rate corrected QT (QTc) at therapeutic concentrations. This randomized, placebo- and positive-controlled, crossover, thorough QT study evaluated the effects of therapeutic and supratherapeutic exenatide concentrations on QTc. Methods Intravenous infusion was employed to achieve steady-state supratherapeutic concentrations in healthy subjects within a reasonable duration (i.e. days). Subjects received exenatide, placebo and moxifloxacin, with ECGs recorded pre-therapy and during treatment. Intravenous exenatide was expected to increase heart rate to a greater extent than subcutaneous twice daily or once weekly formulations. To assure proper heart rate correction, a wide range of baseline heart rates was assessed and prospectively defined methodology was applied to determine the optimal QT correction. Results Targeted steady-state plasma exenatide concentrations were exceeded (geometric mean ± SEM 253 ± 8.5 pg ml−1, 399 ± 11.9 pg ml−1 and 627 ± 21.2 pg ml−1). QTcP, a population-based method, was identified as the most appropriate heart rate correction and was prespecified for primary analysis. The upper bound of the two-sided 90% confidence interval for placebo-corrected, baseline-adjusted QTcP (ΔΔQTcP) was <10 ms at all time points and exenatide concentrations. The mean of three measures assessed at the highest steady-state plasma exenatide concentration of ∼500 pg ml−1 (ΔΔQTcPavg) was −1.13 [−2.11, −0.15). No correlation was observed between ΔΔQTcP and exenatide concentration. Assay sensitivity was confirmed with moxifloxacin. Conclusions These results demonstrated that exenatide, at supratherapeutic concentrations, does not prolong QTc and provide an example of methodology for QT assessment of drugs with an inherent heart rate effect.

Comparison of Manual and Automated Measurements of the QT Interval in Healthy Volunteers: An Analysis of Five Thorough QT Studies

We analyzed five crossover, thorough QT (TQT) studies to compare automated, manual, and computer‐assisted (CA) measurement methods. All the methods detected moxifloxacin‐induced, baseline‐adjusted, placebo‐subtracted mean changes in Fridericia‐corrected QT interval (QTcF), with peak effect ranging from 10 to 21 ms. The variability associated with manual and CA measurements was generally 5–28% greater than that associated with automated methods. The performances of automated, manual, and CA measurements were comparable for the purpose of demonstrating assay sensitivity in TQT studies with healthy volunteers.

Are women more susceptible than men to drug-induced QT prolongation? Concentration-QTc modelling in a phase 1 study with oral rac-sotalol.

AIM To study the differences in QTc interval on ECG in response to a single oral dose of rac-sotalol in men and women. METHODS Continuous 12-lead ECGs were recorded in 28 men and 11 women on a separate baseline day and following a single oral dose of 160 mg rac-sotalol on the following day. ECGs were extracted at prespecified time points and upsampled to 1000 Hz and analyzed manually in a central ECG laboratory on the superimposed median beat. Concentration-QTc analyses were performed using a linear mixed effects model. RESULTS Rac-sotalol produced a significant reduction in heart rate in men and in women. An individual correction method (QTc I) most effectively removed the heart rate dependency of the QTc interval. Mean QTc I was 10 to 15 ms longer in women at all time points on the baseline day. Rac-sotalol significantly prolonged QTc I in both genders. The largest mean change in QTc I (ΔQTc I) was greater in females (68 ms (95% confidence interval (CI) 59, 76 ms) vs. 27 ms (95% CI 22, 32 ms) in males). Peak rac-sotalol plasma concentration was higher in women than in men (mean Cmax 1.8 μg ml(-1) (range 1.1-2.8) vs. 1.4 μg ml(-1) (range 0.9-1.9), P = 0.0009). The slope of the concentration-ΔQTc I relationship was steeper in women (30 ms per μg ml(-1) vs. 23 ms per μg ml(-1) in men; P = 0.0135). CONCLUSIONS The study provides evidence for a greater intrinsic sensitivity to rac-sotalol in women than in men for drug-induced delay in cardiac repolarization.

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 QTcF (ΔΔQTcF) 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 QTcF 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.

Effect of ceralifimod (ONO‐4641) on lymphocytes and cardiac function: Randomized, double‐blind, placebo‐controlled trial with an open‐label fingolimod arm

This randomized, double‐blind, placebo‐controlled, 6‐arm, parallel‐design study investigated cardiac and hematological pharmacodynamic effects of ceralifimod (ONO‐4641), a selective sphingosine‐1‐phosphate (S1P) receptor modulator, over a broad dose range in direct comparison with the nonselective S1P modulator fingolimod. Healthy subjects were assigned to ceralifimod (0.01, 0.025, 0.05, or 0.10 mg), fingolimod (0.5 mg), or placebo once daily for 14 days (n = 24 per group). After 14 days of treatment, mean absolute lymphocyte count percentage change from baseline was greatest in the fingolimod (‐62%) and ceralifimod 0.10 mg (‐56%) groups. On treatment cessation, lymphocyte recovery was faster in the ceralifimod versus the fingolimod group. Ceralifimod showed dose‐ and concentration‐dependent chronotropic effect. Cardiac effects in the fingolimod group were dependent on fingolimod‐P concentrations. Maximum mean heart rate (HR) effect on day 1 was larger with fingolimod (placebo‐adjusted change from time‐matched baseline HR [ΔΔHR], −14.9 beats per minute [bpm]) versus ceralifimod (ΔΔHR, −6.2 and −12.0 bpm for the 0.05‐ and 0.10‐mg doses, respectively). Ceralifimods effect on the PR interval was minor. Safety biomarker results suggest that potential therapeutic doses of ceralifimod, in particular the 0.05‐mg dose, might result in reduced occurrence of bradycardia, atrioventricular block absolute lymphocyte count and grade 3/4 lymphopenia compared with fingolimod 0.5 mg.

Early treatment of cold sores with topical ME-609 decreases the frequency of ulcerative lesions: A randomized, double-blind, placebo-controlled, patient-initiated clinical trial

BACKGROUND Prior pilot studies support the use of antiviral medications with topical corticosteroids for herpes simplex labialis (HSL). ME-609 (Xerese, Xerclear) is a combination of 5% acyclovir and 1% hydrocortisone developed for the topical treatment of HSL. OBJECTIVES The primary study end point was the prevention of ulcerative HSL lesions. METHODS In all, 2437 patients with a history of HSL were randomized to self-initiate treatment with ME-609, 5% acyclovir in ME-609 vehicle, or ME-609 vehicle (placebo) at the earliest sign of a cold sore recurrence. Cream was applied 5 times/d for 5 days. A total of 1443 patients experienced a recurrence and initiated treatment with ME-609 (n = 601), acyclovir (n = 610), or placebo (n = 232). RESULTS Of patients receiving ME-609, 42% did not develop an ulcerative lesion compared with 35% of patients receiving acyclovir in ME-609 vehicle (P = .014) and 26% of patients receiving placebo (P < .0001). In patients with ulcerative lesions, healing times were reduced in the ME-609 and acyclovir groups compared with placebo (P < .01 for both). The cumulative lesion area for all lesions was reduced 50% in patients receiving ME-609 compared with the placebo group (P < .0001). There were no differences among groups in the number of patients with positive herpes simplex virus cultures. The side-effect profile was similar among treatments. LIMITATIONS The study did not contain a group treated with a topical corticosteroid alone. CONCLUSIONS ME-609 prevented progression of cold sores to ulcerative lesions and significantly reduced the cumulative lesion area compared with acyclovir and placebo. ME-609 treatment offers additional therapeutic benefit compared with therapy with topical acyclovir alone.