Analysis of on-treatment cancer safety events with daprodustat versus conventional erythropoiesis-stimulating agents-post hoc analyses of the ASCEND-ND and ASCEND-D trials.

BACKGROUND: The prespecified on-treatment analysis of ASCEND-ND (NCT02876835) raised concerns about a higher relative risk of cancer-related adverse events (AEs) with daprodustat vs darbepoetin in patients with anaemia of CKD. This concern was not observed in dialysis patients in ASCEND-D (NCT02879305). METHODS: ASCEND-ND randomized 3872 patients to daprodustat or darbepoetin. ASCEND-D randomized 2964 patients to daprodustat or conventional erythropoiesis-stimulating agents (ESAs). In both studies ESA comparators used different dosing intervals (3/week, 1/week, every 2 or every 4 weeks). The prespecified on-treatment approach examined relative risks for cancer AEs up to the last dose date + 1 day. In these analyses, owing to different dosing intervals between arms, Cox models were used to estimate the daprodustat effect by various follow-up periods (censoring at last dose date, last dose date + dosing intervals, or end of study). RESULTS: In ASCEND-ND, the safety of daprodustat vs darbepoetin on cancer-related AEs depended on the duration of follow-up after last dose date: hazard ratio (HR) 1.04 [95% confidence interval (CI) 0.77, 1.40] at end of study [HR 1.12 (95% CI 0.81, 1.56) for last dose date + dosing interval; HR 1.50 (95% CI 1.04, 2.15) for last dose date + 1 day]. In ASCEND-D, no excess risk of cancer-related AEs was observed with any model examined. CONCLUSIONS: Prespecified on-treatment analyses for cancer-related AEs appeared to result in biased risk estimates in ASCEND-ND by preferentially under-counting events from patients assigned to darbepoetin. Analyses accounting for longer darbepoetin dosing intervals, or extending follow-up, resulted in attenuation of effect estimates towards neutrality, similar to ASCEND-D, where ESA comparator dosing intervals are closer to daprodustat. TRIAL REGISTRATION: The ASCEND-ND trial is registered with ClinicalTrials.gov (NCT02876835); the ASCEND-D trial is registered with ClinicalTrials.gov (NCT02879305).

Three Times Weekly Dosing of Daprodustat versus Conventional Epoetin for Treatment of Anemia in Hemodialysis Patients: ASCEND-TD: A Phase 3 Randomized, Double-Blind, Noninferiority Trial.

BACKGROUND AND OBJECTIVES: Daprodustat is a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI) being investigated for the treatment of anemia of CKD. In this noninferiority trial, we compared daprodustat administered three times weekly with epoetin alfa (epoetin) in patients on prevalent hemodialysis switching from a prior erythropoiesis-stimulating agent (ESA). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Patients on hemodialysis with a baseline hemoglobin of 8-11.5 g/dl receiving an ESA were randomized 2:1 to daprodustat three times weekly (n=270) or conventional epoetin (n=137) for 52 weeks. Dosing algorithms aimed to maintain hemoglobin between 10 and 11 g/dl. The primary end point was mean change in hemoglobin from baseline to the average during the evaluation period (weeks 28-52). The principal secondary end point was average monthly intravenous iron dose. Other secondary end points included BP and hemoglobin variability. RESULTS: Daprodustat three times weekly was noninferior to epoetin for mean change in hemoglobin (model-adjusted mean treatment difference [daprodustat-epoetin], -0.05; 95% confidence interval, -0.21 to 0.10). During the evaluation period, mean (SD) hemoglobin values were 10.45 (0.55) and 10.51 (0.85) g/dl for daprodustat and epoetin groups, respectively. Responders (defined as mean hemoglobin during the evaluation period in the analysis range of 10 to 11.5 g/dl) were 80% in the daprodustat group versus 64% in the epoetin group. Proportionately fewer participants in the daprodustat group versus the epoetin group had hemoglobin values either below 10 g/dl or above 11.5 g/dl during the evaluation period. Mean monthly intravenous iron use was not significantly lower with daprodustat versus epoetin. The effect on BP was similar between groups. The percentage of treatment-emergent adverse events was similar between daprodustat (75%) and epoetin (79%). CONCLUSIONS: Daprodustat was noninferior to epoetin in hemoglobin response and was generally well tolerated. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Anemia Studies in Chronic Kidney Disease: Erythropoiesis via a Novel Prolyl Hydroxylase Inhibitor Daprodustat-Three Times Weekly Dosing in Dialysis (ASCEND-TD), NCT03400033.

The ASCEND-ND trial: study design and participant characteristics.

BACKGROUND: Anaemia is common in chronic kidney disease (CKD) and assessment of the risks and benefits of new therapies is important. METHODS: The Anaemia Study in CKD: Erythropoiesis via a Novel prolyl hydroxylase inhibitor Daprodustat-Non-Dialysis (ASCEND-ND) trial includes adult patients with CKD Stages 3-5, not using erythropoiesis-stimulating agents (ESAs) with screening haemoglobin (Hb) 8-10 g/dL or receiving ESAs with screening Hb of 8-12 g/dL. Participants were randomized to daprodustat or darbepoetin alfa (1:1) in an open-label trial (steering committee- and sponsor-blinded), with blinded endpoint assessment. The co-primary endpoints are mean change in Hb between baseline and evaluation period (average over Weeks 28-52) and time to first adjudicated major adverse cardiovascular (CV) event. Baseline characteristics were compared with those of participants in similar anaemia trials. RESULTS: Overall, 3872 patients were randomized from 39 countries (median age 67 years, 56% female, 56% White, 27% Asian and 10% Black). The median baseline Hb was 9.9 g/dL, blood pressure was 135/74 mmHg and estimated glomerular filtration rate was 18 mL/min/1.73 m2. Among randomized patients, 53% were ESA non-users, 57% had diabetes and 37% had a history of CV disease. At baseline, 61% of participants were using renin-angiotensin system blockers, 55% were taking statins and 49% were taking oral iron. Baseline demographics were similar to those in other large non-dialysis anaemia trials. CONCLUSION: ASCEND-ND will define the efficacy and safety of daprodustat compared with darbepoetin alfa in the treatment of patients with anaemia associated with CKD not on dialysis.

Daprodustat for the Treatment of Anemia in Patients Not Undergoing Dialysis.

BACKGROUND: Daprodustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor. In patients with chronic kidney disease (CKD) who are not undergoing dialysis, the efficacy and safety of daprodustat, as compared with the conventional erythropoiesis-stimulating agent darbepoetin alfa, are unknown. METHODS: In this randomized, open-label, phase 3 trial with blinded adjudication of cardiovascular outcomes, we compared daprodustat with darbepoetin alfa for the treatment of anemia in patients with CKD who were not undergoing dialysis. The primary outcomes were the mean change in the hemoglobin level from baseline to weeks 28 through 52 and the first occurrence of a major adverse cardiovascular event (MACE; a composite of death from any cause, nonfatal myocardial infarction, or nonfatal stroke). RESULTS: Overall, 3872 patients were randomly assigned to receive daprodustat or darbepoetin alfa. The mean (±SD) baseline hemoglobin levels were similar in the two groups. The mean (±SE) change in the hemoglobin level from baseline to weeks 28 through 52 was 0.74±0.02 g per deciliter in the daprodustat group and 0.66±0.02 g per deciliter in the darbepoetin alfa group (difference, 0.08 g per deciliter; 95% confidence interval [CI], 0.03 to 0.13), which met the prespecified noninferiority margin of -0.75 g per deciliter. During a median follow-up of 1.9 years, a first MACE occurred in 378 of 1937 patients (19.5%) in the daprodustat group and in 371 of 1935 patients (19.2%) in the darbepoetin alfa group (hazard ratio, 1.03; 95% CI, 0.89 to 1.19), which met the prespecified noninferiority margin of 1.25. The percentages of patients with adverse events were similar in the two groups. CONCLUSIONS: Among patients with CKD and anemia who were not undergoing dialysis, daprodustat was noninferior to darbepoetin alfa with respect to the change in the hemoglobin level from baseline and with respect to cardiovascular outcomes. (Funded by GlaxoSmithKline; ASCEND-ND ClinicalTrials.gov number, NCT02876835.).

An open-label study to determine the pharmacokinetics and safety of migalastat HCl in subjects with impaired renal function and healthy subjects with normal renal function.

OBJECTIVES: Renal function may progressively decline in patients with Fabry disease. This study assessed pharmacokinetics, safety, and tolerability of a single oral dose of migalastat HCl 150 mg in subjects with normal or mildly, moderately, or severely impaired renal function. METHODS: Volunteers were enrolled into two cohorts stratified for renal function calculated using the Cockcroft-Gault equation for creatinine clearance. Pharmacokinetic parameters determined were: area under the concentration-time curve (AUC) from time zero to the last measurable concentration postdose (AUC0-t ) and extrapolated to infinity (AUC0-∞ ), maximum observed concentration (Cmax ), time to Cmax (tmax ), concentration at 48 hours postdose (C48h ), terminal elimination half-life (t1/2 ), oral clearance (CL/F), and apparent terminal elimination rate constant (λz) (ClinicalTrials.gov registration: NCT01730469). RESULTS: Thirty-two subjects enrolled and completed the study (Cohort 1: n = 24; Cohort 2: n = 8). Migalastat clearance decreased with increasing renal impairment, resulting in increases in migalastat HCl plasma t1/2 , AUC0-∞ , and C48h compared with subjects with normal renal function. Incidence of adverse events was comparable across all renal function groups. CONCLUSIONS: Plasma migalastat clearance decreased as degree of renal impairment increased. Data from the migalastat HCl clinical program will guide dosing and intervals for patients with Fabry disease with renal impairment.

Evaluation of ventricular arrhythmias in early clinical pharmacology trials and potential consequences for later development.

This white paper, prepared by members of the Cardiac Safety Research Consortium, discusses several important issues regarding the evaluation of ventricular arrhythmias in early clinical pharmacology trials and their potential consequences for later clinical drug development. Ventricular arrhythmias are infrequent but potentially important medical events whose occurrence in early clinical pharmacology trials can dramatically increase safety concerns. Given the increasing concern with all potential safety signals and the resultant more extensive electrocardiographic monitoring of subjects participating in early phase trials, an important question must be addressed: Are relatively more frequent observations of ventricular arrhythmias related simply to more extensive monitoring, or are they genuinely related to the drug under development? The discussions in this paper provide current thinking and suggestions for addressing this question.

The QT and Tp-e intervals in left and right chest leads: comparison between patients with systemic and pulmonary hypertension.

BACKGROUND: Action potential duration in the right ventricle is normally shorter than that in the left. We tested the hypothesis that there may be intrinsic differences in the QT and Tp-e (an interval from the peak to the end of the T wave) intervals between the left and right chest leads that can be exaggerated by systemic hypertension but attenuated by pulmonary hypertension in humans. METHODS: Electrocardiograms in the left (V4L-V6L) and right (V4R-V6R) chest leads were obtained in 40 healthy individuals, 29 patients with systemic hypertension and left ventricular hypertrophy, and 15 patients with pulmonary hypertension. RESULTS: In healthy individuals, the corrected QT (QTc) and corrected Tp-e [T(p-e)c] intervals were 421+/-5 and 86+/-3 milliseconds in V4L through V6L, respectively, significantly longer than those recorded from V4R through V6R (383+/-5 and 62+/-4 milliseconds, respectively; P<.01). Left ventricular hypertrophy prolonged the QTc interval in V4L through V6L (456+/-5 milliseconds), exaggerating the difference in the QTc interval between the left and right chest leads (61+/-4 vs 40+/-3 milliseconds in healthy control subjects; P<.01). Left ventricular hypertrophy also resulted in a small but significant increase in the T(p-e)c interval in V4L through V6L (97+/-3 vs 86+/-3 milliseconds in control subjects; P<.05) but exerted no significant effect on the T(p-e)c interval in the right. In contrast, pulmonary hypertension lengthened the QTc interval in the right chest leads, reducing the difference in the QTc interval between the left and right chest leads (3+/-8 vs 40+/-3 milliseconds in control subjects; P<.01). CONCLUSIONS: There are intrinsic differences in the QT and Tp-e intervals between V4L-V6L and V4R-V6R that are significantly amplified by systemic hypertension but markedly attenuated by pulmonary hypertension.

ECG repolarization waves: their genesis and clinical implications.

The electrocardiographic (ECG) manifestation of ventricular repolarization includes J (Osborn), T, and U waves. On the basis of biophysical principles of ECG recording, any wave on the body surface ECG represents a coincident voltage gradient generated by cellular electrical activity within the heart. The J wave is a deflection with a dome that appears on the ECG after the QRS complex. A transmural voltage gradient during initial ventricular repolarization, which results from the presence of a prominent action potential notch mediated by the transient outward potassium current (I(to)) in epicardium but not endocardium, is responsible for the registration of the J wave on the ECG. Clinical entities that are associated with J waves (the J-wave syndrome) include the early repolarization syndrome, the Brugada syndrome and idiopathic ventricular fibrillation related to a prominent J wave in the inferior leads. The T wave marks the final phase of ventricular repolarization and is a symbol of transmural dispersion of repolarization (TDR) in the ventricles. An excessively prolonged QT interval with enhanced TDR predisposes people to develop torsade de pointes. The malignant "R-on-T" phenomenon, i.e., an extrasystole that originates on the preceding T wave, is due to transmural propagation of phase 2 reentry or phase 2 early afterdepolarization. A pathological "U" wave as seen with hypokalemia is the consequence of electrical interaction among ventricular myocardial layers at action potential phase 3 of which repolarization slows. A physiological U wave is thought to be due to delayed repolarization of the Purkinje system.

Preclinical strategies to assess QT liability and torsadogenic potential of new drugs: the role of experimental models.

The recognition of QT prolongation and torsade de pointes (TdP) in humans has resulted in the re-labeling of some drugs and the removal of others from the market in the past decade. Recent regulatory guidelines have recommended a battery of preclinical tests to assess a new drug for the QT liability in humans. The assessment includes the effect of a drug on: 1) the ionic current in stable cell lines expressing hERG channel; 2) action potential duration (APD) measured in isolated ventricular tissues; 3) the QTc interval and TdP in animals in vivo; and 4) APD, the QT interval, transmural dispersion of repolarization (TDR) and TdP potential in the isolated arterially-perfused ventricular wedge preparation. Because a noncardiac drug with an incidence of TdP even less than 0.1% can be potentially removed from the market, the experimental models used for preclinical testing have to be high sensitive and specific to the signals related to TdP. Among available experimental models, the rabbit left ventricle wedge preparation exhibits a high sensitivity and a high specificity in the identification of compounds positive and negative for QT prolongation and TdP. This is attributed to the fact that the preparation demonstrates strong signals related to QT prolongation in response to even a weaker QT prolonging agent. Signals specifically pertinent to the development of TdP, ie, early afterdepolarization (EAD) and an increase in TDR can be detected as well. The preclinical data obtained from the wedge preparation correlate well with clinical outcomes.

Overview of the management of atrial fibrillation: what is the current state of the art?

Management of Atrial Fibrillation. There are three fundamental approaches to the management of atrial fibrillation (AF): rate control, rhythm control, and anticoagulation. Selecting a course of treatment requires a thorough knowledge of these therapeutic alternatives. This article explores treatment options, including the relative benefits of rate control versus rhythm control, which are complicated by the lack of highly effective and safe antiarrhythmic drugs. Anticoagulation is also an important issue in AF management, and warfarin effectively reduces the incidence of thromboembolic events in AF patients. The use of warfarin, however, presents its own complications. We conclude that individualization of therapy is paramount when treating AF.