Efficacy and Safety of Acoramidis in Transthyretin Amyloid Cardiomyopathy.

BACKGROUND: Transthyretin amyloid cardiomyopathy is characterized by the deposition of misfolded monomeric transthyretin (TTR) in the heart. Acoramidis is a high-affinity TTR stabilizer that acts to inhibit dissociation of tetrameric TTR and leads to more than 90% stabilization across the dosing interval as measured ex vivo. METHODS: In this phase 3, double-blind trial, we randomly assigned patients with transthyretin amyloid cardiomyopathy in a 2:1 ratio to receive acoramidis hydrochloride at a dose of 800 mg twice daily or matching placebo for 30 months. Efficacy was assessed in the patients who had an estimated glomerular filtration rate of at least 30 ml per minute per 1.73 m2 of body-surface area. The four-step primary hierarchical analysis included death from any cause, cardiovascular-related hospitalization, the change from baseline in the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level, and the change from baseline in the 6-minute walk distance. We used the Finkelstein-Schoenfeld method to compare all potential pairs of patients within strata to generate a P value. Key secondary outcomes were death from any cause, the 6-minute walk distance, the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary, and the serum TTR level. RESULTS: A total of 632 patients underwent randomization. The primary analysis favored acoramidis over placebo (P<0.001); the corresponding win ratio was 1.8 (95% confidence interval [CI], 1.4 to 2.2), with 63.7% of pairwise comparisons favoring acoramidis and 35.9% favoring placebo. Together, death from any cause and cardiovascular-related hospitalization contributed more than half the wins and losses to the win ratio (58% of all pairwise comparisons); NT-proBNP pairwise comparisons yielded the highest ratio of wins to losses (23.3% vs. 7.0%). The overall incidence of adverse events was similar in the acoramidis group and the placebo group (98.1% and 97.6%, respectively); serious adverse events were reported in 54.6% and 64.9% of the patients. CONCLUSIONS: In patients with transthyretin amyloid cardiomyopathy, the receipt of acoramidis resulted in a significantly better four-step primary hierarchical outcome containing components of mortality, morbidity, and function than placebo. Adverse events were similar in the two groups. (Funded by BridgeBio Pharma; ATTRibute-CM ClinicalTrials.gov number, NCT03860935.).

Aficamten for Symptomatic Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: One of the major determinants of exercise intolerance and limiting symptoms among patients with obstructive hypertrophic cardiomyopathy (HCM) is an elevated intracardiac pressure resulting from left ventricular outflow tract obstruction. Aficamten is an oral selective cardiac myosin inhibitor that reduces left ventricular outflow tract gradients by mitigating cardiac hypercontractility. METHODS: In this phase 3, double-blind trial, we randomly assigned adults with symptomatic obstructive HCM to receive aficamten (starting dose, 5 mg; maximum dose, 20 mg) or placebo for 24 weeks, with dose adjustment based on echocardiography results. The primary end point was the change from baseline to week 24 in the peak oxygen uptake as assessed by cardiopulmonary exercise testing. The 10 prespecified secondary end points (tested hierarchically) were change in the Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS), improvement in the New York Heart Association (NYHA) functional class, change in the pressure gradient after the Valsalva maneuver, occurrence of a gradient of less than 30 mm Hg after the Valsalva maneuver, and duration of eligibility for septal reduction therapy (all assessed at week 24); change in the KCCQ-CSS, improvement in the NYHA functional class, change in the pressure gradient after the Valsalva maneuver, and occurrence of a gradient of less than 30 mm Hg after the Valsalva maneuver (all assessed at week 12); and change in the total workload as assessed by cardiopulmonary exercise testing at week 24. RESULTS: A total of 282 patients underwent randomization: 142 to the aficamten group and 140 to the placebo group. The mean age was 59.1 years, 59.2% were men, the baseline mean resting left ventricular outflow tract gradient was 55.1 mm Hg, and the baseline mean left ventricular ejection fraction was 74.8%. At 24 weeks, the mean change in the peak oxygen uptake was 1.8 ml per kilogram per minute (95% confidence interval [CI], 1.2 to 2.3) in the aficamten group and 0.0 ml per kilogram per minute (95% CI, -0.5 to 0.5) in the placebo group (least-squares mean between-group difference, 1.7 ml per kilogram per minute; 95% CI, 1.0 to 2.4; P<0.001). The results for all 10 secondary end points were significantly improved with aficamten as compared with placebo. The incidence of adverse events appeared to be similar in the two groups. CONCLUSIONS: Among patients with symptomatic obstructive HCM, treatment with aficamten resulted in a significantly greater improvement in peak oxygen uptake than placebo. (Funded by Cytokinetics; SEQUOIA-HCM ClinicalTrials.gov number, NCT05186818.).

Intermediate-effect size p.Arg637Gln in FHOD3 increases risk of HCM and is associated with an aggressive phenotype in homozygous carriers.

Formin homology 2 domain-containing 3 (FHOD3) gene has emerged as one of the main non-sarcomeric genes associated with hypertrophic cardiomyopathy (HCM), but no cases of biallelic variants associated with disease have been described to date. From 2014 until 2021, FHOD3 was evaluated in our center by next-generation sequencing in 22 806 consecutive unrelated probands. The p.Arg637Gln variant in FHOD3 was enriched in our HCM cohort (284 of 9668 probands; 2.94%) compared with internal controls (64 of 11 480; 0.59%) and gnomAD controls (373 of 64 409; 0.58%), with ORs of 5.40 (95% CI: 4.11 to 7.09) and 5.19 (95% CI: 4.44 to 6.07). The variant affects a highly conserved residue localised in a supercoiled alpha helix considered a clustering site for HCM variants, and in heterozygosis can act as a predisposing factor (intermediate-effect variant) for HCM, with an estimated penetrance of around 1%. Additionally, seven homozygous carriers of p.Arg637Gln in FHOD3 were identified. All but one (unaffected) showed an early presentation and a severe HCM phenotype. All this information suggest that p.Arg637Gln variant in FHOD3 is a low-penetrant variant, with an intermediate effect, that contributes to the development of HCM in simple heterozygosis, being associated with a more severe phenotype in homozygous carriers.

Alcoholic cardiomyopathy: an update.

Alcohol-induced cardiomyopathy (AC) is an acquired form of dilated cardiomyopathy (DCM) caused by prolonged and heavy alcohol intake in the absence of other causes. The amount of alcohol required to produce AC is generally considered as >80 g/day over 5 years, but there is still some controversy regarding this definition. This review on AC focuses on pathogenesis, which involves different mechanisms. Firstly, the direct toxic effect of ethanol promotes oxidative stress in the myocardium and activation of the renin-angiotensin system. Moreover, acetaldehyde, the best-studied metabolite of alcohol, can contribute to myocardial damage impairing actin-myosin interaction and producing mitochondrial dysfunction. Genetic factors are also involved in the pathogenesis of AC, with DCM-causing genetic variants in patients with AC, especially titin-truncating variants. These findings support a double-hit hypothesis in AC, combining genetics and environmental factors. The synergistic effect of alcohol with concomitant conditions such as hypertension or liver cirrhosis can be another contributing factor leading to AC. There are no specific cardiac signs and symptoms in AC as compared with other forms of DCM. However, natural history of AC differs from DCM and relies directly on alcohol withdrawal, as left ventricular ejection fraction recovery in abstainers is associated with an excellent prognosis. Thus, abstinence from alcohol is the most crucial step in treating AC, and specific therapies are available for this purpose. Otherwise, AC should be treated according to current guidelines of heart failure with reduced ejection fraction. Targeted therapies based on AC pathogenesis are currently being developed and could potentially improve AC treatment in the future.

Survival in a Real-World Cohort of Patients With Transthyretin Amyloid Cardiomyopathy Treated With Tafamidis: An Analysis From the Transthyretin Amyloidosis Outcomes Survey (THAOS).

BACKGROUND: In the pivotal Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), tafamidis significantly reduced mortality rates, leading to its approval in many countries for the treatment of transthyretin amyloid cardiomyopathy (ATTR-CM). Real-world evidence on survival in patients with ATTR-CM following tafamidis treatment has not been extensively reported. METHODS AND RESULTS: The Transthyretin Amyloidosis Outcomes Survey (THAOS) was a longitudinal, observational, phase 4 study of patients with transthyretin amyloidosis and asymptomatic participants carrying pathogenic transthyretin variants. Patients from THAOS with a predominantly cardiac phenotype at enrollment were included, and survival was analyzed according to tafamidis treatment status (treated or untreated). Results are based on the completed THAOS dataset. In tafamidis-treated (n = 587) and tafamidis-untreated (n = 854) patients, respectively, median age at enrollment was 77.7 and 76.4 years, 91.8% and 90.0% were male, and 91.8% and 83.8% had wild-type disease. Survival rates (95% CI) at 30 and 42 months, respectively, were 84.4% (80.5-87.7) and 76.8% (70.9-81.7) in tafamidis-treated patients, and 70.0% (66.4-73.2) and 59.3% (55.2-63.0) in tafamidis-untreated patients. Survival rates in genotype subgroups (wild-type and variant) were similar to those of the overall cohort. Survival rates were better in a contemporary cohort, as reflected by a sensitivity analysis performed in patients enrolled after vs before 2019. No new safety signals were identified. CONCLUSIONS: In this real-world cohort of patients with ATTR-CM, survival rates were higher than in ATTR-ACT and consistent with more recent reports, suggesting early diagnosis and treatment with tafamidis has improved life expectancy in ATTR-CM. These results provide further evidence supporting tafamidis' safety and effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00628745.

Efficacy and Safety of Aficamten in Symptomatic Nonobstructive Hypertrophic Cardiomyopathy: Results From the REDWOOD-HCM Trial, Cohort 4.

BACKGROUND: This open-label phase 2 trial evaluated the safety and efficacy of aficamten in patients with nonobstructive hypertrophic cardiomyopathy (nHCM). METHODS: Patients with symptomatic nHCM (left ventricular outflow tract obstruction gradient ≤ 30 mmHg, left ventricular ejection fraction [LVEF] ≥ 60%, N-terminal pro-B-type natriuretic peptide [NT-proBNP] > 300 pg/mL) received aficamten 5-15 mg once daily (doses adjusted according to echocardiographic LVEF) for 10 weeks. RESULTS: We enrolled 41 patients (mean ± SD age 56 ± 16 years; 59% female). At Week 10, 22 (55%) patients experienced an improvement of ≥ 1 New York Heart Association class; 11 (29%) became asymptomatic. Clinically relevant improvements in Kansas City Cardiomyopathy Questionnaire Clinical Summary Scores occurred in 22 (55%) patients. Symptom relief was paralleled by reductions in NT-proBNP levels (56%; P < 0.001) and high-sensitivity cardiac troponin I (22%; P < 0.005). Modest reductions in LVEF (mean ± SD) of -5.4% ± 10 to 64.6% ± 9.1 were observed. Three (8%) patients had asymptomatic reduction in LVEF < 50% (range: 41%-48%), all returning to normal after 2 weeks of washout. One patient with prior history of aborted sudden cardiac death experienced a fatal arrhythmia during the study. CONCLUSIONS: Aficamten administration for symptomatic nHCM was generally safe and was associated with improvements in heart failure symptoms and cardiac biomarkers. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04219826.

Long-term tafamidis efficacy in patients with transthyretin amyloid cardiomyopathy by baseline left ventricular ejection fraction.

AIMS: Patients with transthyretin amyloid cardiomyopathy (ATTR-CM) present with diverse left ventricular ejection fraction (LVEF). This study assessed tafamidis efficacy by baseline LVEF in the phase 3 Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and its long-term extension (LTE) study. METHODS AND RESULTS: Patients were randomized to 30 months of tafamidis or placebo treatment in ATTR-ACT. On completion, patients could join an LTE study to receive tafamidis. All-cause mortality (death, heart transplant, or cardiac mechanical assist device implantation) from baseline to the end of follow-up was assessed in patients continuously treated with tafamidis (80 mg meglumine or 61 mg free acid) or delayed tafamidis treatment (placebo in ATTR-ACT; tafamidis in the LTE study) according to baseline LVEF (<50% or ≥50%). Supportive outcomes were evaluated over a shorter follow-up. Patients with baseline LVEF <50% (n = 177: 88 tafamidis- and 89 placebo-treated) had signs of more severe heart failure, a higher proportion were Black, and had variant ATTR-CM than those with LVEF ≥50% (n = 171: 85 tafamidis- and 86 placebo-treated). At the end of follow-up (median 60-64 months), all-cause mortality was numerically higher in patients with baseline LVEF <50%; however, consistent with supportive findings, continuous tafamidis treatment was associated with a 47% reduction in mortality risk compared with delayed tafamidis treatment in patients with LVEF <50% and ≥50% (hazard ratio 0.53 [95% confidence interval 0.367-0.758]; p < 0.001, and 0.53 [0.344-0.818]; p < 0.01, respectively). CONCLUSIONS: Early initiation of tafamidis is associated with reduced mortality in patients with ATTR-CM, irrespective of initial LVEF value. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT01994889, NCT02791230.

Pathogenic truncating filamin C mutations presenting as acute myocarditis: a case series with insights from cardiac magnetic resonance and histological analysis.

Background: The exact mechanisms underlying the pathogenesis of myocarditis are not always understood, but there is emerging evidence to suggest that genetic factors may play a significant role. Case summary: Herein, we present six cases in which clinical, biochemical, and cardiovascular magnetic resonance data were consistent with myocarditis, and genetic testing subsequently revealed pathogenic filamin C (FLNC) mutations. Three patients presented with ventricular arrhythmias, two with severe biventricular dysfunction, and two suffered sudden cardiac arrest. Three received an implantable cardioverter defibrillator, and one underwent heart transplantation. Cascade testing was useful in identifying other relatives with FLNC mutation. We also present relevant histology results of myocardial specimens showing the presence of lymphocytic infiltration and inflammation, further supporting the potential association between FLNC mutations and a myocarditis phenotype. Discussion: Genetic testing of affected individuals for FLNC mutations and cascade screening in the setting of acute myocarditis may be considered in selected clinical context, such as in acute myocarditis accompanied by severe left ventricular systolic dysfunction, biventricular failure, significant ventricular arrhythmias, or right ventricular involvement.

Impact of vutrisiran on exploratory cardiac parameters in hereditary transthyretin-mediated amyloidosis with polyneuropathy.

AIMS: HELIOS-A was a Phase 3, open-label study of vutrisiran, an RNA interference therapeutic, in patients with hereditary transthyretin (ATTRv) amyloidosis with polyneuropathy. This analysis evaluated vutrisiran's impact on exploratory cardiac endpoints in HELIOS-A patients. METHODS AND RESULTS: Patients were randomized 3:1 to subcutaneous vutrisiran 25 mg every 3 months or intravenous patisiran 0.3 mg/kg every 3 weeks (reference group) for 18 months. Exploratory cardiac endpoints included change from baseline in N-terminal prohormone of brain-type natriuretic peptide (NT-proBNP) and echocardiographic parameters versus external placebo (APOLLO study). The modified intent-to-treat (mITT) population comprised randomized patients receiving any study drug (n = 122). A cardiac subpopulation with evidence of cardiac amyloid involvement (n = 40) was prespecified. 99mTc scintigraphy exploratory assessments in a planned vutrisiran-treated cohort at select sites were compared with baseline. At Month 18, vutrisiran demonstrated beneficial effects on NT-proBNP versus external placebo in the mITT and cardiac subpopulations (adjusted geometric mean fold change ratio [95% confidence interval] 0.480 [0.383-0.600], p = 9.606 × 10-10 and 0.491 [0.337-0.716], p = 0.0004, respectively). Benefits or trends towards benefit in echocardiographic parameters versus external placebo were observed for both populations. In 99mTc scintigraphy assessments, 32/47 (68.1%) and 31/48 (64.6%) patients exhibited reduced normalized left ventricular total uptake and heart-to-contralateral lung ratio, respectively. Perugini grade was reduced or unchanged versus baseline in 55/57 (96.5%) evaluable patients. No increase in cardiac adverse events was observed with vutrisiran versus external placebo. CONCLUSIONS: Vutrisiran demonstrated evidence of potential benefit on cardiac manifestations in patients with ATTRv amyloidosis with polyneuropathy, with an acceptable safety profile.

Clinical and Genotype Characteristics and Symptom Migration in Patients With Mixed Phenotype Transthyretin Amyloidosis from the Transthyretin Amyloidosis Outcomes Survey.

INTRODUCTION: Transthyretin amyloidosis (ATTR amyloidosis) is primarily associated with a cardiac or neurologic phenotype, but a mixed phenotype is increasingly described. METHODS: This study describes the mixed phenotype cohort in the Transthyretin Amyloidosis Outcomes Survey (THAOS). THAOS is an ongoing, longitudinal, observational survey of patients with ATTR amyloidosis, including both hereditary (ATTRv) and wild-type disease, and asymptomatic carriers of pathogenic transthyretin variants. Baseline characteristics of patients with a mixed phenotype (at enrollment or reclassified during follow-up) are described (data cutoff: January 4, 2022). RESULTS: Approximately one-third of symptomatic patients (n = 1185/3542; 33.5%) were classified at enrollment or follow-up as mixed phenotype (median age, 66.5 years). Of those, 344 (29.0%) were reclassified to mixed phenotype within a median 1-2 years of follow-up. Most patients with mixed phenotype had ATTRv amyloidosis (75.7%). The most frequent genotypes were V30M (38.9%) and wild type (24.3%). CONCLUSIONS: These THAOS data represent the largest analysis of a real-world mixed phenotype ATTR amyloidosis population to date and suggest that a mixed phenotype may be more prevalent than previously thought. Patients may also migrate from a primarily neurologic or cardiologic presentation to a mixed phenotype over time. These data reinforce the need for multidisciplinary evaluation at initial assessment and follow-up of all patients with ATTR amyloidosis. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00628745.

Histological Typing in Patients With Cardiac Amyloidosis: JACC Review Topic of the Week.

Cardiac amyloidosis is increasingly recognized as a treatable form of heart failure. Highly effective specific therapies have recently become available for the 2 most frequent forms of cardiac amyloidosis: immunoglobulin light chain amyloidosis and transthyretin (ATTR) amyloidosis. Nevertheless, initiation of specific therapies requires recognition of cardiac amyloidosis and appropriate characterization of the amyloid type. Although noninvasive diagnosis is possible for ATTR cardiac amyloidosis, histological demonstration and typing of amyloid deposits is still required for a substantial number of patients with ATTR and in all patients with light chain amyloidosis and other rarer forms of cardiac amyloidosis. Amyloid histological typing can be performed using different techniques: mass spectrometry, immunohistochemistry, and immunoelectron microscopy. This review describes which patients require histological confirmation of cardiac amyloidosis along with when and how to type amyloid deposits in histologic specimens. Furthermore, it covers the characteristics and limitations of the different typing methods that are available in clinical practice.

Advancing Transthyretin Amyloidosis Drug Development in an Evolving Treatment Landscape: Amyloidosis Forum Meeting Proceedings.

INTRODUCTION: Hereditary transthyretin amyloidosis (ATTRv, also referred to as hATTR; ORPHA 271861) and wild-type ATTR amyloidosis (ATTRwt; ORPHA 330001) are rare, progressive, systemic protein misfolding disorders with heterogeneous clinical presentations. ATTRv and ATTRwt amyloidosis are characterized by the deposition of amyloid fibrils in multiple organs including the heart, nerves, eyes, and soft tissues. The management of ATTR amyloidosis is complex because of its multisystemic nature and progression despite available treatment options. Morbidity is high and there are many unmet medical needs for patients. While contemporary ATTR amyloidosis cohorts are diagnosed earlier, have lower risk disease and lower mortality compared with the previous era, these advances coupled with the emergence of effective disease-modifying therapies have confounded the design of future prospective clinical trials and interpretation of historical control data. MAIN BODY: The Amyloidosis Forum is a public-private partnership between the US Food and Drug Administration Center for Drug Evaluation and Research and the nonprofit Amyloidosis Research Consortium ( www.arci.org ). This article summarizes proceedings from the 21 June 2023 Amyloidosis Forum on advancing drug development in ATTR amyloidosis in an evolving treatment landscape. The Forum focused on elements of clinical trial design to address these challenges and discussed their strengths and weaknesses from multiple stakeholder perspectives (i.e., patient, sponsor, statistician, clinician, and regulatory authorities). CONCLUSION: Given rapid evolution of natural history in ATTR amyloidosis, the utility of historical control data is limited. Leveraging contemporary real-world data is essential for clinical trial design. Evidence generation from clinical trials should address clinically relevant questions. Key factors in successful trial design must be informed by up-to-date data on natural history, prognostic factors, clinically meaningful thresholds, and sharing available clinical trial data. The Amyloidosis Forum includes the community of patients with ATTR amyloidosis, the physicians who treat them, and the sponsors and regulators who collectively stand ready to support further studies in order to develop novel effective therapies.

Age- and Sex-Related Differences in Patients With Wild-Type Transthyretin Amyloidosis: Insights From THAOS.

Background: Wild-type transthyretin amyloidosis (ATTRwt amyloidosis) is primarily diagnosed in elderly men but diagnoses in younger patients and women have recently increased. Objectives: The purpose of this study was to examine age- and sex-related differences in patients with ATTRwt amyloidosis enrolled in the THAOS (Transthyretin Amyloidosis Outcomes Survey). Methods: THAOS was a global, longitudinal, observational survey of patients with transthyretin amyloidosis, including both hereditary and wild-type disease, and asymptomatic carriers of pathogenic transthyretin gene variants. Patient characteristics at enrollment were analyzed by age at enrollment and sex (data cutoff date: August 1, 2022). Results: Of 1,251 patients with ATTRwt amyloidosis, 13.7%, 49.1%, 34.5%, and 2.8% were aged <70 years, 70 to 79 years, 80 to 89 years, and ≥90 years, respectively. The proportion of women increased with age, from 4.1% in patients aged <70 years to 14.3% in patients aged ≥90 years. In the respective age groups, median time from symptom onset to diagnosis overall (male, female) was 1.7 (1.3, 5.2), 2.0 (2.0, 2.2), 1.8 (1.9, 0.8), and 0.7 (0.6, 2.5) years. A Karnofsky Performance Status score ≤70 was observed in 17.1%, 30.1%, 46.1%, and 44.4% of patients aged <70 years, 70 to 79 years, 80 to 89 years, and ≥90 years, respectively. Conclusions: In this THAOS analysis of patients with ATTRwt amyloidosis, patients were diagnosed an average of 2 years after symptom onset, with the greatest diagnostic delay in women aged <70 years at 5 years. Patients were predominantly men, but the proportion of women increased with age. A substantial proportion of patients had significant functional impairment regardless of age. (Transthyretin Amyloidosis Outcome Survey [THAOS]; NCT00628745).

Characterization and natural history of patients with LMNA-related dilated cardiomyopathy in the phase 3 REALM-DCM trial.

AIMS: LMNA-related dilated cardiomyopathy (DCM) is a rare disease with an incompletely defined phenotype. The phase 3 REALM-DCM trial evaluated a potential disease-modifying therapy for LMNA-related DCM but was terminated due to futility without safety concern. This study utilized pooled data from REALM-DCM to descriptively characterize the phenotype and progression of LMNA-related DCM in a contemporary cohort of patients using common heart failure (HF) measures. METHODS: REALM-DCM enrolled patients with stable LMNA-related DCM, an implanted cardioverter defibrillator or cardiac resynchronization therapy defibrillator, and New York Heart Association (NYHA) Class II/III HF symptoms. RESULTS: Between 2018 and 2022, 77 patients took part in REALM-DCM. The median patient age was 53 years (range: 23-72), and 57% were male. Overall, 88% of patients had a pathogenic or likely pathogenic LMNA variant, and 12% had a variant of uncertain significance with a concordant phenotype. Among patients with confirmed sequencing, 55% had a missense variant. Atrial fibrillation was present in 60% of patients; 79% of all patients had NYHA Class II and 21% had NYHA Class III HF symptoms at baseline. Median (range) left ventricular ejection fraction (LVEF), 6 min walk test (6MWT) distance, Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) score and N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration at baseline were 42% (23-62), 403 m (173-481), 67 (18-97) and 866 pg/mL (57-5248), respectively. LVEF, 6MWT distance and KCCQ-OS score were numerically lower in patients who had NYHA Class III versus II symptoms at baseline (LVEF: 38% vs. 43%; 6MWT distance: 326 vs. 413 m; and KCCQ-OS score: 43 vs. 70), whereas NT-proBNP concentration was higher (1216 vs. 799 pg/mL). Median follow-up was 73 weeks (range: 0.4-218; 73 in NYHA Class II and 75 in NYHA Class III). Patients displayed variable change from baseline in 6MWT, KCCQ-OS and NT-proBNP values during follow-up. Overall, 25% of patients experienced ventricular tachycardia, and 8% had ventricular fibrillation. Ten (13%) patients met the composite endpoint of worsening HF (adjudicated HF-related hospitalization or urgent care visit) or all-cause death; six had NYHA Class II and four had NYHA Class III at baseline. All-cause mortality occurred in 6 (8%) patients; three had NYHA Class II and three had NYHA Class III symptoms at baseline. CONCLUSIONS: Findings confirm the significant morbidity and mortality associated with LMNA-related DCM despite the standard of care management. Typical measures of HF, including 6MWT distance, KCCQ-OS score and NT-proBNP concentration, were variable but correlated with NYHA class. An unmet treatment need remains among patients with LMNA-related DCM. NCT03439514.

REALM-DCM: A Phase 3, Multinational, Randomized, Placebo-Controlled Trial of ARRY-371797 in Patients With Symptomatic LMNA-Related Dilated Cardiomyopathy.

BACKGROUND: LMNA (lamin A/C)-related dilated cardiomyopathy is a rare genetic cause of heart failure. In a phase 2 trial and long-term extension, the selective p38α MAPK (mitogen-activated protein kinase) inhibitor, ARRY-371797 (PF-07265803), was associated with an improved 6-minute walk test at 12 weeks, which was preserved over 144 weeks. METHODS: REALM-DCM (NCT03439514) was a phase 3, randomized, double-blind, placebo-controlled trial in patients with symptomatic LMNA-related dilated cardiomyopathy. Patients with confirmed LMNA variants, New York Heart Association class II/III symptoms, left ventricular ejection fraction ≤50%, implanted cardioverter-defibrillator, and reduced 6-minute walk test distance were randomized to ARRY-371797 400 mg twice daily or placebo. The primary outcome was a change from baseline at week 24 in the 6-minute walk test distance using stratified Hodges-Lehmann estimation and the van Elteren test. Secondary outcomes using similar methodology included change from baseline at week 24 in the Kansas City Cardiomyopathy Questionnaire-physical limitation and total symptom scores, and NT-proBNP (N-terminal pro-B-type natriuretic peptide) concentration. Time to a composite outcome of worsening heart failure or all-cause mortality and overall survival were evaluated using Kaplan-Meier and Cox proportional hazards analyses. RESULTS: REALM-DCM was terminated after a planned interim analysis suggested futility. Between April 2018 and October 2022, 77 patients (aged 23-72 years) received ARRY-371797 (n=40) or placebo (n=37). No significant differences (P>0.05) between groups were observed in the change from baseline at week 24 for all outcomes: 6-minute walk test distance (median difference, 4.9 m [95% CI, -24.2 to 34.1]; P=0.82); Kansas City Cardiomyopathy Questionnaire-physical limitation score (2.4 [95% CI, -6.4 to 11.2]; P=0.54); Kansas City Cardiomyopathy Questionnaire-total symptom score (5.3 [95% CI, -4.3 to 14.9]; P=0.48); and NT-proBNP concentration (-339.4 pg/mL [95% CI, -1131.6 to 452.7]; P=0.17). The composite outcome of worsening heart failure or all-cause mortality (hazard ratio, 0.43 [95% CI, 0.11-1.74]; P=0.23) and overall survival (hazard ratio, 1.19 [95% CI, 0.23-6.02]; P=0.84) were similar between groups. No new safety findings were observed. CONCLUSIONS: Findings from REALM-DCM demonstrated futility without safety concerns. An unmet treatment need remains among patients with LMNA-related dilated cardiomyopathy. REGISTRATION: URL: https://classic.clinicaltrials.gov; Unique Identifiers: NCT03439514, NCT02057341, and NCT02351856.

N-terminal pro-B-type natriuretic peptide post-discharge monitoring in the management of patients with heart failure and preserved ejection fraction - a randomized trial: The NICE study.

AIMS: There is a lack of specific studies assessing the impact of natriuretic peptide monitoring in the post-discharge management of patients with heart failure (HF) and preserved ejection fraction (HFpEF), throughout the vulnerable phase following acute HF hospitalization. The NICE study aims to assess the clinical benefit of incorporating N-terminal pro-B-type natriuretic peptide (NT-proBNP) into the post-discharge management of HFpEF patients. METHODS AND RESULTS: Individuals admitted with HFpEF (left ventricular ejection fraction >50%) were included in a multicentre randomized controlled study employing an open-label design with event blinding (NCT02807168). Upon discharge, 157 patients were randomly allocated to either NT-proBNP monitoring (n = 79) or no access to NT-proBNP (control group, n = 78) during pre-scheduled visits at 2, 4 and 12 weeks. Clinical endpoints were evaluated at 6 months. The primary endpoint of HF rehospitalizations occurred in 12.1% patients, without significant differences observed between the NT-proBNP monitoring group (12.8%) and the control group (11.4%) (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.47-2.81, p = 0.760). Regarding secondary endpoints, the NT-proBNP monitoring group demonstrated a significantly lower risk of death (1.3% vs. 10.1%; HR 0.12, 95% CI 0.02-0.98; p = 0.048), whereas non-HF hospitalizations (12.8% vs. 19.0%, p = 0.171) and any adverse clinical event (26.9% vs. 36.7%, p = 0.17) did not reach statistical significance [Correction added on 29 April 2024, after first online publication: In the preceding sentence, "95% CI 0.02 - 0.09" has been corrected to "95% CI 0.02 - 0.98; p = 0.048" in this version.]. Awareness of NT-proBNP levels were associated with higher doses of diuretics and renin-angiotensin system inhibitors (angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers) in the NT-proBNP monitoring group. CONCLUSIONS: Post-discharge monitoring of NT-proBNP in HFpEF patients did not exhibit an association with reduced rates of HF hospitalization in this study. Nonetheless, it appears to enhance global clinical management by optimizing medical therapies and contributing to improved overall survival.

Prevalence of transthyretin cardiac amyloidosis in patients with heart failure with preserved ejection fraction: the PRACTICA study.

INTRODUCTION AND OBJECTIVES: Transthyretin cardiac amyloidosis (ATTR-CA) is a frequent cause of heart failure with preserved ejection fraction (HFpEF). This study aimed to determine the prevalence of ATTR-CA in HFpEF patients in a multicenter nationwide study. METHODS: Consecutive ambulatory or hospitalized patients aged ≥ 50 years with HFpEF and left ventricle hypertrophy ≥ 12 mm were studied at 20 Spanish hospitals. Screening for CA was initiated according to the usual clinical practice at each center. Positive scintigraphs were analyzed centrally. RESULTS: A total of 422 patients were included, of whom 387 underwent further screening for CA. Sixty-five patients (16.8%) were diagnosed with ATTR-CA, and none was younger than 75 years. Prevalence increased with age. Among these patients, 60% were men, with a mean age of 85.3 ± 5.2 years, mean left ventricular ejection fraction of 60.3 ± 7.6%, and a mean maximum left ventricular wall thickness of 17.2 (range, 12-25) mm. Most of the patients were in New York Heart Association class II (48.4%) or III (46.8%). In addition to being older than patients without ATTR-CA, patients with ATTR-CA had higher median NT-proBNP levels (3801 [2266-7132] vs 2391 [1141-4796] pg/mL; P = .003). There was no statistically significant difference in the prevalence of ATTR-CA by sex (19.7% in men and 13.8% in women, P = .085). A genetic variant (ATTRv) was found in approximately 7% (4/56) of the patients. CONCLUSIONS: This multicenter nationwide study found that the prevalence of ATTR-CA was 16.8%, confirming it as a significant contributor to HFpEF in patients of both sexes with left ventricular hypertrophy older than 75 years.

Mavacamten Treatment for Symptomatic Obstructive Hypertrophic Cardiomyopathy: Interim Results From the MAVA-LTE Study, EXPLORER-LTE Cohort.

BACKGROUND: Data assessing the long-term safety and efficacy of mavacamten treatment for symptomatic obstructive hypertrophic cardiomyopathy are needed. OBJECTIVES: The authors sought to evaluate interim results from the EXPLORER-Long Term Extension (LTE) cohort of MAVA-LTE (A Long-Term Safety Extension Study of Mavacamten in Adults Who Have Completed EXPLORER-HCM; NCT03723655). METHODS: After mavacamten or placebo withdrawal at the end of the parent EXPLORER-HCM (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy; NCT03470545), patients could enroll in MAVA-LTE. Patients received mavacamten 5 mg once daily; adjustments were made based on site-read echocardiograms. RESULTS: Between April 9, 2019, and March 5, 2021, 231 of 244 eligible patients (94.7%) enrolled in MAVA-LTE (mean age: 60 years; 39% female). At data cutoff (August 31, 2021) 217 (93.9%) remained on treatment (median time in study: 62.3 weeks; range: 0.3-123.9 weeks). At 48 weeks, patients showed improvements in left ventricular outflow tract (LVOT) gradients (mean change ± SD from baseline: resting: -35.6 ± 32.6 mm Hg; Valsalva: -45.3 ± 35.9 mm Hg), N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels (median: -480 ng/L; Q1-Q3: -1,104 to -179 ng/L), and NYHA functional class (67.5% improved by ≥1 class). LVOT gradients and NT-proBNP reductions were sustained through 84 weeks in patients who reached this timepoint. Over 315 patient-years of exposure, 8 patients experienced an adverse event of cardiac failure, and 21 patients had an adverse event of atrial fibrillation, including 11 with no prior history of atrial fibrillation. Twelve patients (5.2%) developed transient reductions in site-read echocardiogram left ventricular ejection fraction of <50%, resulting in temporary treatment interruption; all recovered. Ten patients discontinued treatment due to treatment-emergent adverse events. CONCLUSIONS: Mavacamten treatment showed clinically important and durable improvements in LVOT gradients, NT-proBNP levels, and NYHA functional class, consistent with EXPLORER-HCM. Mavacamten treatment was well tolerated over a median 62-week follow-up.

A Simple Frailty Score Predicts Survival and Early Mortality in Systemic AL Amyloidosis.

Systemic AL amyloidosis is a challenging disease for which many patients are considered frail in daily clinical practice. However, no study has so far addressed frailty and its impact on the outcome of these patients. We built a simple score to predict mortality based on three frailty-associated variables: age, ECOG performance status (<2 vs. ≥2) and NT-proBNP (<8500 vs. ≥8500 ng/L). Four-hundred and sixteen consecutive newly diagnosed patients diagnosed at ten sites from the Spanish Myeloma Group were eligible for the study. The score was developed in a derivation cohort from a referral center, and it was externally validated in a multicenter cohort. Multivariate analysis showed that the three variables were independent predictors of survival. The score was able to discriminate four groups of patients in terms of overall survival and early mortality in both cohorts. Comorbidity was also analyzed with the Charlson comorbidity index, but it did not reach statistical significance in the model. A nomogram was created to easily estimate the mortality risk of each patient at each time point. This score is a simple, robust, and efficient approach to dynamically assess frailty-dependent mortality both at diagnosis and throughout follow-up. The optimal treatment for frail AL amyloidosis patients remains to be determined but we suggest that the estimation of frailty-associated risk could complement current staging systems, adding value in clinical decision-making in this complex scenario.

Extended septal myectomy versus alcohol septal ablation: clinical results at a national referral centre.

OBJECTIVES: Extended septal myectomy and alcohol septal ablation are 2 invasive treatments for hypertrophic obstructive cardiomyopathy. Our goal was to compare which of these techniques achieved a higher reduction in gradients, improvement in New York Heart Association (NYHA) functional class and reduction in medical treatment. METHODS: It is a single-centre observational and retrospective analysis. We used multivariable regression analyses to assess the association of ablation/myectomy with different outcomes. The odds ratio or coefficient along with the 95% confidence interval was estimated according to the group and adjusted for the corresponding preprocedural variables and EuroSCORE II. RESULTS: A total of 78 patients underwent septal myectomy, and 25 patients underwent alcohol septal ablation. Basal and Valsalva gradients after myectomy were reduced to a higher degree in comparison to ablation: 21.0 mmHg [P < 0.001, 95% confidence interval -30.7; -11.3], and 34.3 mmHg (P < 0.001, -49.1; -19.5) respectively. Those patients who received a myectomy had a lower probability of having moderate mitral regurgitation (odds ratio = 0.18, P = 0.054). Patients after septal myectomy were more likely to be NYHA functional class I (80.4%), whereas patients after ablation were more likely to be NYHA functional class III (48%). Both groups continued with beta-blocker therapy, but disopyramide could be discontinued after the myectomy in more cases (20%-36% vs 59%-1.3%; P < 0.001), and there was a tendency to discontinue calcium channel blockers (48%-16% vs 15.4-3.8%; P = 0.054). CONCLUSIONS: After adjustment using preprocedural gradients and EuroSCORE II, myectomy achieves greater reduction in left ventricular outflow tract gradients compared to septal ablation.