Does Characterization of Phenotypic Heterogeneity Provide Mechanistic Insights or Influence the Response to Treatment? Experience in Positive and Neutral Trials in Patients With Heart Failure and a Preserved Ejection Fraction
At a time when there was no unifying hypothesis and no broadly effective treatments for heart failure with a preserved ejection fraction (HFpEF), it was proposed that HFpEF represented a multitude of different disorders. Accordingly, characterization of phenotypic heterogeneity was envisioned as a means of identifying novel causal pathways that could lead to new treatments while simultaneously discerning patients who would selectively benefit from a specific therapy. However, efforts over the past decade to characterize phenotypic diversity in diverse and complex ways have not achieved these goals. Subgroup analyses of neutral HFpEF trials have failed to reliably identify responders to treatments. Neither proteomics nor unsupervised cluster analysis across multiple phenotypic domains has yielded reproducible results (even in the same dataset), elucidated novel mechanistic pathways for new drug development, or identified patients most likely to benefit from treatment. In marked contrast to these efforts to characterize phenotypic heterogeneity, large-scale trials in HFpEF enrolled patients using broad eligibility criteria, and they established the benefits of sodium-glucose cotransporter 2 inhibitors and mineralocorticoid receptor antagonists without evidence for subgroup effects. However, it is noteworthy that patients enrolled in recent large-scale HFpEF trials were characterized by general uniformity with respect to the presence of excess adiposity, with central obesity being a feature of the vast majority of enrolled participants. Of note, patients with obesity showed particularly large benefits when treated with effective drugs for HFpEF. These observations raise the possibility that, if these trials had permitted the participation of patients with class III obesity or with lower natriuretic peptide levels, the magnitude of the observed treatment effects might have been greater than originally reported. These findings are consistent with a central role for visceral adiposity (and the secretion of an altered suite of adipokines) in the pathogenesis of HFpEF. Therefore, because the field of HFpEF has a unifying hypothesis (applicable to the large majority of patients), enrolled a broad population of patients in large-scale trials without subgroup interactions, and has several broadly applicable effective treatments (as is true for heart failure with a reduced ejection fraction), the motivation to characterize phenotypic heterogeneity in HFpEF in complex ways may no longer be supported or needed.
Effects of Acoramidis on Kidney Function in Transthyretin Amyloid Cardiomyopathy
BACKGROUND: Acoramidis achieves near-complete (≥90%) transthyretin stabilization and is approved to reduce cardiovascular-related mortality and hospitalization in transthyretin amyloid cardiomyopathy. Its effects on kidney function are not well characterized. METHODS: Data from randomized phase 2 (N=49) and phase 3 (N=632) studies in transthyretin amyloid cardiomyopathy were included. The estimated glomerular filtration rate (eGFR) slope was generated using a linear spline mixed-effects model. The urinary albumin-to-creatinine ratio was measured longitudinally. Relationships between changes in kidney function and clinical outcomes were explored using Cox proportional hazards models. RESULTS: Acoramidis initiation resulted in a modest acute dip in eGFR that was dose-dependent, reversible, and not associated with adverse kidney-related events. At Day 28, the mean (±SE) dip in eGFR from baseline with acoramidis was 8.5±0.48 mL/min per 1.73 m 2 ; the placebo-corrected reduction in the urinary albumin-to-creatinine ratio was 15.5% (95% CI, 0.4%–28.4%; P =0.044). The rate of decline in kidney function (chronic eGFR slope) was significantly improved with acoramidis versus placebo (−1.01 versus −3.48 mL/min per 1.73 m 2 per year; P <0.001), and the reduction in the urinary albumin-to-creatinine ratio was sustained (13.7% [95% CI, 1.7%–24.2%]; P =0.026) over time. Concomitant tafamidis use did not influence the chronic eGFR slope in either arm. Comparing acoramidis versus placebo subgroups with acute eGFR dips ≥ the median (4.89 mL/min per 1.73 m 2 ) favored acoramidis for all-cause mortality or cardiovascular-related hospitalization (hazard ratio, 0.42 [95% CI, 0.22–0.78]; P =0.006; P interaction=0.043) and cardiovascular-related hospitalization (hazard ratio, 0.34 [95% CI, 0.17–0.66]; P =0.002, P interaction=0.025). Within the placebo arm, eGFR dips portended worse outcomes. CONCLUSIONS: Acoramidis initiation resulted in an acute dip in eGFR and reductions in both the chronic eGFR slope and urinary albumin-to-creatinine ratio versus placebo without adverse kidney-related events. Acoramidis effects on kidney function may be mediated through direct kidney-protective hemodynamic effects. Importantly, the acute dip in eGFR was associated with a reduced risk of adverse clinical outcomes within the first year. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifiers: NCT03458130, NCT03536767, NCT03860935, NCT04988386.
Predicted versus observed outcomes in the ALT-FLOW early feasibility study
Abstract Background and Aims Whether hemodynamic and symptomatic benefits of the APTURE left atrial-to-coronary sinus shunt translate into clinical outcome benefit in heart failure with left ventricular ejection fraction >40% remains unknown. Methods In this post hoc analysis of ALT-FLOW EFS patients undergoing APTURE implantation, Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score-predicted 1-year all-cause mortality was compared with observed mortality by Kaplan-Meier analysis of adjudicated events. Heart failure hospitalization (HFH) rates were compared for the 12 months before vs after implantation. Additional analyses included stratification by baseline sodium-glucose cotransporter 2 inhibitor (SGLT2i) use and N-terminal pro-B-type natriuretic peptide (NT-proBNP), recurrent HFH cumulative hazard estimation (Nelson-Aalen), and H2FPEF score calculation. Results Among 95 patients (mean age 70.9 ± 8.5 years; 50% women; 93% New York Heart Association Class III; 85.9% with H2FPEF score >3), MAGGIC-predicted 1-year mortality was 13.0%. Observed 1-year survival was significantly higher than predicted (94.7% vs 87.0%; P=0.04), consistent across SGLT2i subgroups (log-rank P=0.59). The proportion of patients with HFH declined from 37.9% pre implantation to 9.6% post implantation (P<0.0001), with event rates falling from 0.61 to 0.21 per patient-year (P<0.001) and a 1-year cumulative hazard of recurrent HFH of 0.19 (95% confidence interval, 0.12-0.31). HFHs were evenly distributed across NT-proBNP strata. Conclusions In ALT-FLOW EFS, observed 1-year mortality was lower than MAGGIC-predicted mortality, and post implantation HFH rates were lower than pre implantation rates. These hypothesis-generating findings will require confirmation in the randomized, sham-controlled ALT-FLOW II trial.
The ALT FLOW early feasibility study 3-year results assessing left atrial to coronary sinus shunting in HFpEF
Abstract Introduction Left atrial-to-coronary sinus (LA-to-CS) shunting through the APTURE transcatheter shunt system aims to unload the LA while preserving the interatrial septum. This article aims to examine the 3-year health status, functional capacity, and clinical outcomes of the ALT-FLOW Early Feasibility Study (EFS). Methods Device safety, patency, and echocardiographic parameters, but also symptoms, health status, and exercise capacity were assessed in patients with left ventricular ejection fraction (LVEF) > 40% (n & 95). Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score predicted 3-year all-cause mortality was compared with observed mortality assessed by Kaplan–Meier analysis using adjudicated events. Predicted and observed HF hospitalization (HFH)-free survival rates were also compared. Results At 3 years, the safety profile remained stable with no new safety signals, and all implanted shunts remained patent. 76.3% of patients improved by at least one NYHA class, and mean KCCQ Overall Summary Scores increased by 25 points from baseline (P < .0001). The 6-min walk distance improved by an average of 39 m (P & .002). These benefits were consistent regardless of baseline pulmonary vascular resistance (PVR). Right heart echocardiographic parameters after 3 years were stable, though a reduction in TAPSE was observed, primarily in the high PVR subgroup. The observed 3-year survival was significantly higher than the MAGGIC-predicted survival (84.4% vs 70.2, respectively; P & .009), as well as the HFH-free survival (68.0% vs 24.0%, respectively; P < 0001). Conclusion In patients with HF and LVEF >40%, the APTURE LA-to-CS shunting confirmed an acceptable safety profile with stable right heart parameters and sustained improvements in symptoms, quality of life, and functional capacity at 3 years. Observed survival and HFH were superior to MAGGIC predictions.
Vericiguat and mortality in heart failure and reduced ejection fraction: the VICTOR trial
Abstract Background and Aims In the VICTOR trial (NCT05093933), vericiguat was neutral for the primary composite endpoint of cardiovascular death or hospitalization for heart failure (HF). VICTOR was powered to independently assess cardiovascular death. This study reports detailed analysis on the effects of vericiguat on mortality. Methods VICTOR, a double-blind, placebo-controlled, randomized trial, enrolled 6105 ambulatory patients with HF and reduced ejection fraction (HFrEF) without recent worsening and randomized them to vericiguat or placebo. The main outcome for this analysis was the pre-specified secondary endpoint of cardiovascular death. All-cause death, sudden cardiac death, and death related to HF were also assessed. Results Over a median of 19.7 months (inter-quartile range 14.6–25.4), cardiovascular deaths occurred in 292 patients (5.7 deaths per 100 patient-years) and 346 patients (6.8 deaths per 100 patient-years) in the vericiguat and placebo groups, respectively (hazard ratio [HR] 0.83, 95% confidence interval [CI] 0.71–0.97; P = .020). Risk of death from any cause was lower with vericiguat vs placebo (377 [7.3 deaths per 100 patient-years] vs 440 [8.6 deaths per 100 patient-years]; HR 0.84, 95% CI 0.74–0.97; P = .015). Sudden cardiac death and HF-related deaths were lower with vericiguat vs placebo (1.6 vs 2.2 events per 100 patient-years; HR 0.75, 95% CI 0.56–0.99; P = .042 and 1.7 vs 2.4 events per 100 patient-years; HR 0.71, 95% CI 0.54–0.94; P = .016, respectively). Lower mortality rates were consistent across subgroups including baseline therapy. Consistent cardiovascular and all-cause mortality benefit was seen across baseline N-terminal pro-B-type natriuretic peptide levels. Conclusions In ambulatory well-treated participants with HFrEF, vericiguat was associated with clinically meaningful reductions in the key secondary outcome of cardiovascular death, as well as all-cause mortality.
Semaglutide and diuretic use in obesity-related heart failure with preserved ejection fraction: a pooled analysis of the STEP-HFpEF and STEP-HFpEF-DM trials
Abstract Background and Aims In the STEP-HFpEF trial programme, treatment with semaglutide resulted in multiple beneficial effects in patients with obesity-related heart failure with preserved ejection fraction (HFpEF). Efficacy may vary according to baseline diuretic use, and semaglutide treatment could modify diuretic dose. Methods In this pre-specified analysis of pooled data from the STEP-HFpEF and STEP-HFpEF-DM trials (n = 1145), which randomized participants with HFpEF and body mass index ≥ 30 kg/m2 to once weekly semaglutide 2.4 mg or placebo for 52 weeks, we examined whether efficacy and safety endpoints differed by baseline diuretic use, as well as the effect of semaglutide on loop diuretic use and dose changes over the 52-week treatment period. Results At baseline, across no diuretic (n = 220), non-loop diuretic only (n = 223), and loop diuretic [<40 (n = 219), 40 (n = 309), and >40 (n = 174) mg/day furosemide equivalents] groups, there was progressively higher prevalence of hypertension and atrial fibrillation; and greater severity of obesity and heart failure. Over 52 weeks of treatment, semaglutide had a consistent beneficial effect on change in body weight across diuretic use categories (adjusted mean difference vs. placebo ranged from −8.8% [95% confidence interval (CI) −10.3, −6.3] to −6.9% [95% CI −9.1, −4.7] from no diuretics to the highest loop diuretic dose category; interaction P = .39). Kansas City Cardiomyopathy Questionnaire clinical summary score improvement was greater in patients on loop diuretics compared to those not on loop diuretics (adjusted mean difference vs. placebo: +9.3 [6.5; 12.1] vs. +4.7 points [1.3, 8.2]; P = .042). Semaglutide had consistent beneficial effects on all secondary efficacy endpoints (including 6 min walk distance) across diuretic subgroups (interaction P = .24–.92). Safety also favoured semaglutide vs. placebo across the diuretic subgroups. From baseline to 52 weeks, loop diuretic dose decreased by 17% in the semaglutide group vs. a 2.4% increase in the placebo group (P < .0001). Semaglutide (vs. placebo) was more likely to result in loop diuretic dose reduction (odds ratio [OR] 2.67 [95% CI 1.70, 4.18]) and less likely dose increase (OR 0.35 [95% CI 0.23, 0.53]; P < .001 for both) from baseline to 52 weeks. Conclusions In patients with obesity-related HFpEF, semaglutide improved heart failure-related symptoms and physical limitations across diuretic use subgroups, with more pronounced benefits among patients receiving loop diuretics at baseline. Reductions in weight and improvements in exercise function with semaglutide vs. placebo were consistent in all diuretic use categories. Semaglutide also led to a reduction in loop diuretic use and dose between baseline and 52 weeks. Clinical Trial Registration NCT04788511 and NCT04916470.
Hierarchical End Points in Prior Heart Failure Trials and the HEART-FID Trial
BACKGROUND: Clinical trials in heart failure (HF) traditionally use time-to-event analyses focusing on death and hospitalization for HF. These time-to-first event analyses may have more limited abilities to assess the probability of benefiting from a therapy, especially if that benefit manifests as improved functional status rather than reduced risk of death or HF hospitalization. Hierarchical end points including clinical outcomes and patient status measures allow for ranked evaluation of outcomes in 1 metric assessing whether patients randomized to intervention or control are more likely to derive an overall benefit while also allowing more patients to contribute to the primary outcome. METHODS: We review the rationale for using hierarchical end points in HF trials, provide examples of HF trials that used this type of end point, and discuss its use in the HEART-FID trial (Randomized Placebo-Controlled Trial of Ferric Carboxymaltose as Treatment for Heart Failure With Iron Deficiency), the largest HF trial to date implementing a hierarchical end point analysis for the primary outcome. RESULTS: Using a hierarchical end point as the primary outcome allows for the inclusion of different types of outcomes in 1 ranked end point, making it possible to more holistically assess the potential utility of a new therapy on patient well-being and outcomes. CONCLUSIONS: Hierarchical end points assess the potential utility of a new therapy on patient well-being and outcome more holistically than time-to-first event analysis. Trials that would not have been feasible due to decreasing rates of death and hospitalization in the HF population can use hierarchical end points to successfully power studies to identify promising HF therapies. The HEART-FID trial used hierarchical end points to better determine the role of intravenous ferric carboxymaltose in patients with HF. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03037931.
Effects of Semaglutide on Symptoms, Function, and Quality of Life in Patients With Heart Failure With Preserved Ejection Fraction and Obesity: A Prespecified Analysis of the STEP-HFpEF Trial
BACKGROUND: Patients with heart failure (HF) with preserved ejection fraction (HFpEF) and obesity experience a high burden of symptoms and functional impairment, and a poor quality of life. In the STEP-HFpEF trial (Research Study to Investigate How Well Semaglutide Works in People Living With Heart Failure and Obesity), once-weekly semaglutide 2.4 mg improved symptoms, physical limitations, and exercise function, and reduced inflammation and body weight. This prespecified analysis investigated the effects of semaglutide on the primary and confirmatory secondary end points across the range of the Kansas City Cardiomyopathy Questionnaire (KCCQ) scores at baseline and on all key summary and individual KCCQ domains. METHODS: STEP-HFpEF randomly assigned 529 participants with symptomatic HF, an ejection fraction of ≥45%, and a body mass index of ≥30 kg/m 2 to once-weekly semaglutide 2.4 mg or placebo for 52 weeks. Dual primary end points change in KCCQ-Clinical Summary Score (CSS) and body weight. Confirmatory secondary end points included change in 6-minute walk distance, a hierarchical composite end point (death, HF events, and change in KCCQ-CSS and 6-minute walk distance) and change in C-reactive protein. Patients were stratified by KCCQ-CSS tertiles at baseline. Semaglutide effects on the primary, confirmatory secondary, and select exploratory end points (N-terminal pro-brain natriuretic peptide) were examined across these subgroups. Semaglutide effects on additional KCCQ domains (Total Symptom Score [including symptom burden and frequency], Physical Limitations Score, Social Limitations Score, Quality of Life Score, and Overall Summary Score) were also evaluated. RESULTS: Baseline median KCCQ-CSS across tertiles was 37, 59, and 77 points, respectively. Semaglutide consistently improved primary end points across KCCQ tertiles 1 to 3 (estimated treatment differences [95% CI]: for KCCQ-CSS, 10.7 [5.4 to 16.1], 8.1 [2.7 to 13.4], and 4.6 [–0.6 to 9.9] points; for body weight, –11 [–13.2 to –8.8], –9.4 [–11.5 to –7.2], and –11.8 [–14.0 to –9.6], respectively; P interaction =0.28 and 0.29, respectively); the same was observed for confirmatory secondary and exploratory end points ( P interaction >0.1 for all). Semaglutide-treated patients experienced improvements in all key KCCQ domains (estimated treatment differences, 6.7–9.6 points across domains; P ≤0.001 for all). Greater proportion of semaglutide-treated versus placebo-treated patients experienced at least 5-, 10-, 15-, and 20-point improvements in all KCCQ domains (odds ratios, 1.6–2.9 across domains; P <0.05 for all). CONCLUSIONS: In patients with HFpEF and obesity, semaglutide produced large improvements in HF-related symptoms, physical limitations, exercise function, inflammation, body weight, and N-terminal pro-brain natriuretic peptide, regardless of baseline health status. The benefits of semaglutide extended to all key KCCQ domains. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04788511.
Endpoint adjudication in cardiovascular clinical trials
Abstract Endpoint adjudication (EA) is a common feature of contemporary randomized controlled trials (RCTs) in cardiovascular medicine. Endpoint adjudication refers to a process wherein a group of expert reviewers, known as the clinical endpoint committee (CEC), verify potential endpoints identified by site investigators. Events that are determined by the CEC to meet pre-specified trial definitions are then utilized for analysis. The rationale behind the use of EA is that it may lessen the potential misclassification of clinical events, thereby reducing statistical noise and bias. However, it has been questioned whether this is universally true, especially given that EA significantly increases the time, effort, and resources required to conduct a trial. Herein, we compare the summary estimates obtained using adjudicated vs. non-adjudicated site designated endpoints in major cardiovascular RCTs in which both were reported. Based on these data, we lay out a framework to determine which trials may warrant EA and where it may be redundant. The value of EA is likely greater when cardiovascular trials have nuanced primary endpoints, endpoint definitions that align poorly with practice, sub-optimal data completeness, greater operator variability, and lack of blinding. EA may not be needed if the primary endpoint is all-cause death or all-cause hospitalization. In contrast, EA is likely merited for more nuanced endpoints such as myocardial infarction, bleeding, worsening heart failure as an outpatient, unstable angina, or transient ischaemic attack. A risk-based approach to adjudication can potentially allow compromise between costs and accuracy. This would involve adjudication of a small proportion of events, with further adjudication done if inconsistencies are detected.