ATTR-ACT - Tafamidis for transthyretin amyloid cardiomyopathy

Maurer MS, et al. Tafamidis treatment for patients with transthyretin amyloid cardiomyopathy. NEJM 2018;379:1007-16.

Bottom line:

• In patients with transthyretin amyloid cardiomyopathy (ATTR-CM), tafamidis 20-80 mg/d reduced the risk of death (NNT 8) & cardiovascular hospitalization (NNT 13) over 30 months.

• Based on subgroup analyses, tafamidis may increase CV hospitalizations in patients with NYHA functional class 3 HF at baseline.

• Tafamidis did not increase overall or any specific adverse effects.

Patients (n=441)

• Included

  • 18-90 y/o

  • ATTR, wild-type (ATTRwt) or due to a mutation (ATTRm), confirmed by cardiac or extra-cardiac biopsy

  • ATTR cardiomyopathy confirmed by

    • Echo - End-diastolic interventricular septal wall thickness >12 mm

    • Hx of heart failure (HF) with 1+ HF hospitalizations or clinical evidence of volume overload or NT-proBNP 600+ pg/mL

  • 6-minute walk-test (6MWT) distance >100 m

• Excluded

  • NYHA functional class 4

  • Cause of HF other than ATTR CM, light-chain amyloidosis

  • Receiving other proven/potential therapy for ATTR

    • Hx of liver or heart transplant

    • Diflunisal, doxycycline, tauroursodeoxycholate

  • eGFR <25; ALT/AST >2x ULN; Severe malnutrition (quantified as serum albumin [g/L] * BMI <600)

  • Use of calcium-channel blockers or digoxin

• Baseline characteristics

  • 74 y/o; male (90%); white (80%), black (14%)

  • ATTRwt (76%), ATTRm (24%)

  • NYHA functional class (FC): 1 (~8%), 2 (~59%), 3 (~33%)

  • Kansas City Cardiomyopathy Questionnaire (KCCQ) 66/100

  • 6MWT distance 350 m

  • BP 115/70 mm Hg (supine & standing)

  • Echo: LVEF 48%, interventricular wall thickness ~16 mm

  • NT-proBNP median ~3000

  • Meds: RAAS inhibitor (27%), beta-blocker (29%), diuretic (66-70%), antithrombotic (40%)

Interventions & control

• I: Tafamidis 20 or 80 mg PO once daily

  • If adverse effect, those randomized to 80 mg/d could be reduced to 40 mg/d

• C: Matching placebo

• Adherence: 97% from each group took at least 80% of their doses (assessed by pill count at follow-up visits)

Results @ 30 months

• Primary outcome of death or CV hospitalization: Win ratio: 1.70 (95% confidence interval [CI] 1.26-2.29)

  • “Win ratio” calculated using the Finkelstein-Schoenfeld method

    • Non-parametric test that compares every patient from the intervention group to every patient in the control group in pairwise fashion;

    • First, pairs are compared based on whether each is alive or dead at last common follow-up (e.g. if patient A followed for 2 years, but patient B dropped out at 1 year, then both are compared at year 1);

    • Second, if both are alive or both dead, then there is a draw, & they are compared based on the rate of CV hospitalizations;

    • The win ratio is a tally of all of these comparisons, where higher scores are better. Because this is a ratio, a confidence interval that does not include 1.00 is statistically significant

• Death: Tafamidis 29.5%, placebo 42.9% (NNT 8)

  • Hazard ratio (HR) 0.70 (95%CI 0.51-0.96)

  • No significant subgroup difference based on TTR genotype or NYHA FC

• CV hospitalizations: 52.3% vs 60.5% (NNT 13, relative risk 0.68, 95%CI 0.56-0.81)

  • Rate per patient/year: 0.30 vs 0.46

  • Subgroup based on NYHA class: p<0.001 for interaction; INCREASE with tafamidis in NYHA FC 3

  • Subgroup based on TTR genotype: p=0.11 for interaction

• 6MWT distance vs placebo: +76 m

• Quality of life (KCCQ) vs placebo: +13.6 points (range 0-100, higher scores are better)

• No difference in overall, serious, or any individual adverse effects

Internal validity

• Low risk of allocation, performance, detection & attrition bias

  • Computer-generated randomization stratified by TTR status (wild-type or mutant variant), baseline NYHA class

  • Allocation concealed: Allocation by using interactive web-response system

  • Blinding by use of matching placebo

  • Loss to follow-up <0.5% & modified intention-to-treat (mITT) analysis

ASCEND-HF - Nesiritide for acute decompensated heart failure

O'Connor CM, et al. Effect of nesiritide in patients with acute decompensated heart failure. N Engl J Med 2011;365:32-43.

Bottom line: In patients hospitalized with acute decompensated HF, nesiritide does not provide any clinically meaningful benefit when added to standard care, & increases the risk of symptomatic hypotension (NNH 32).

Context

• Nesiritide, a recombinant form of B-type natriuretic peptide (BNP) & the first therapeutic natriuretic peptide, was approved for use in 2001 based on surrogate benefit (reduction in pulmonary capillary wedge pressure [PCWP]) & reduction in dyspnea at 3 hours compared to placebo or nitroglycerin.
• Meta-analyses of small nesiritide trials found a possible increased risk of AKI & death vs placebo.

Patients (n=7007 analyzed)

• Included:
  • Hospitalized for HF (regardless of EF)
  • Within 24h of initiation of in-hospital IV treatment of HF <24h of enrolment
  • Dyspnea at rest or with minimal activity (ie leading to NYHA functional class 3-4)
  • Plus at least 1 of: RR 20+, pulmonary congestion/edema with rales 1/3 of the way up or more of the lung fields
  • Plus at least 1 objective measure of HF (congestion/edema on CXR, BNP >400 pg/mL or NTproBNP >1000 npg/mL, PCWP >20 mm hg, LVEF <40% in the previous 12 months)
• Excluded:
  • SBP <100 mm Hg, or <110 mm Hg if using IV nitroglycerin
  • Dobutamine (at rate of 5+ ug/kg of body wt/min)
  • Milrinone, levosimendan within 30 days
  • Persistent uncontrolled HTN; ACS; severe pulmonary disease; ESRD with renal replacement therapy; clinically-significant anemia
  • "Other contraindications for vasodilators"
• Baseline characteristics
  • Age 67 y
  • Female 34%
  • PMHx: Ischemic heart disease 60%, HTN 73%, AF 37%
  • Median ~16h from hospitalization to study drug initiation
  • SBP 124, HR 82
  • EF <40% (80%), 40% or more (20%)
  • BNP ~990 pg/mL, NTproBNP ~4500 ph/mL
  • Na 139, SCr ~106 umol/L 
  • Meds: Loop diuretic 95%, ACEI/ARB 60%, BB 58%, MRA 28%, digoxin 27%
• Generalizability: Good; trial population is representative of patients hospitalized for ADHF, excluding those at high risk of hypotension & those on inotropes

Interventions

• I: Nesiritide
  • Optional loading dose: 2 ug/kg IV bolus
  • Maintenance dose: 0.010 ug/kg/min continuous infusion for >24h, max 7 days
  • Median infusion duration 41h (IQR 24-48h)
• C: Matching placebo infusion
• Co-interventions for all: Diuretics, morphine, other vasoactive medications guided by use of a standard-of-care manual

Results

• Co-primary outcome 1: Self-reported dyspnea on 7-point Likert scale (range markedly better to markedly worse)
  • Moderately/markedly better @ 6h: Nesiritide 44.5%, placebo 42.1% (p=0.03)
  • Moderately/markedly better @ 24h: Nesiritide 68.2%, placebo 66.1% (p=0.007)
  • Although these differences were statistically significant, they are not clinically important
• Co-primary outcome 2: All-cause mortality or re-hospitalization for HF @ 30 days:
  • Nesiritide 9.4%, placebo 10.1% (hazard ratio [HR] 0.93, 95% confidence interval 0.9-1.08)
  • Death: 3.6% vs 4.0% (p>0.05)
• Secondary outcomes
  • Persistent/worsening HF or death prior to discharge: Nesiritide 4.2%, placebo 4.8% (p=0.30)
• Adverse effects
  • Symptomatic hypotension: Nesiritide 7.2%, placebo 4.0%, number needed to harm (NNH) 32 (p<0.001)
  • Asymptomatic hypotension: Nesiritide 21.4%, placebo 12.4%, NNH 12
  • eGFR decreased by >25% from baseline: Nesiritide 31.4%, placebo 26.2% (p=0.11)

Internal validity

• Unclear risk of allocation bias (randomization & allocation concealment procedures not adequately reported)
• Low risk of performance & detection bias (double-blind with matching placebo)
• Low risk of attrition bias
  • Modified ITT analysis of all patients who received study drug (98% of randomized)
  • <3% loss-to-follow-up for evaluation of symptoms at 6-24h 

Other studies of nesiritide

• 2000 NEJM study:
  • In the first part of the trial, 127 ADHF patients were randomized to double-blind treatment with nesiritide 0.015 ug/kg/min, nesiritide 0.03/ug/kg/min or placebo. At 6h, nesiritide reduced dyspnea, improved global clinical status & reduced PCWP more than placebo.
  • In the second part of this trial, 305 ADHF patients were randomized to open-label nesiritide 0.015 ug/kg/min, nesiritide 0.03/ug/kg/min or another vasoactive agent (inotrope, nitroglycerin or nitroprusside at attending physician's discretion). There was no difference in any efficacy measure between groups.
• VMAC: This was a double-blind RCT of 489 ADHF patients comparing nesiritide to nitroglycerin IV & placebo x3h, followed by a comparison of nesiritide vs nitroglycerin x24h.
  • By 3h, nesiritide decreased PCWP (-5 mm Hg) & right atrial pressure (-3 mm Hg) more than nitroglycerin (-3 & -2) & placebo (-2 & 0). Nesiritide also reduced dyspnea @ 3h more than placebo, but not nitroglycerin.
  • There were no differences in dyspnea or global clinical status @ 24h. The rate of adverse effects was higher in the nitroglycerin group, largely due to more headaches vs nesiritide. Rates of hypotension were similar between these 2 groups.
• ROSE: In this double-blind trial of 360 ADHF patients with renal dysfunction, there was no difference between nesiritide, dopamine or placebo in cumulative urine output or renal function after 72h of study treatment.

DOSE - Diuretic strategies (low vs high dose & IV bolus vs continuous infusion) for acutely decompensated HF

Bottom line: In patients with acutely decompensated HF patients not in cardiogenic shock,

• Higher versus lower doses of loop diuretics did not significantly affect primary efficacy & safety outcomes
  • However, secondary outcomes consistently demonstrated a lower risk of serious adverse events (NNT 9), more rapid resolution of dyspnea & congestion, & greater weight loss (extra -1.2 kg in first 72h), at the cost of an increased risk of AKIN stage 1 AKI (NNH 12)
• Continuous IV administration of loop diuretics does not appear to have any advantage over q12h IV boluses.

Patients (n=300)

• Included
  • Presented for acutely decompensated HF (ADHF) within 24h
    • Diagnosed based on 1+ symptoms (SOB, orthopnea, edema) & 1+ sign (crackles, peripheral edema, ascites, pulmonary vascular congestion on CXR) of HF
  • Hx of chronic HF (any LV ejection fraction [LVEF])
  • Receiving an oral loop diuretic equivalent to furosemide 80-240 mg/d +/- chronic thiazide diuretic
• Excluded
  • SBP <90 mm Hg
  • SCr >265 umol/L
  • Requiring IV vasodilators or inotropes
• Average baseline characteristics
  • Age 66 y
  • Male ~74%
  • Median time from presentation to randomization ~15h
  • Ischemic CM 57%
  • Hospitalized for HF within 1 y ~75%
  • Home dose of furosemide PO ~130 mg/d
  • Clinical characteristics
    • Orthopnea ~90%
    • SBP 120 mm Hg
    • SpO2 96%
    • JVP 8+ cm 91%
    • LVEF 35% (27% with EF 50%+)
    • NT-proBNP ~680-8200 pg/mL
    • Sodium 138
    • SCr 133 umol/L
  • Meds
    • ACEI/ARB ~65%
    • BB ~85%
    • MRA ~27%

Interventions

• Dose comparison
  • High dose: Daily IV dose = 2.5x total home PO dose
  • Low dose: Daily IV dose = total home PO dose
• Administration method comparison
  • Continuous IV infusion
  • IV bolus dose divided as q12h administration
• Assigned treatment continued for up to 72h, after which treatment was open-label at discretion of treating physician
  • At 48h, could either
    • Increase dose by 50%
    • Maintain same strategy
    • D/C IV & switch to open-label PO
• At 48h:
  • Change to PO diuretics: High 31%, low 17% (p<0.001)
  • Need for dose increase
    • High 9%, low 24% (p=0.003)
    • Continuous 11%, bolus 21% (p=0.01)
• Median dose over first 72h
  • High 773 mg, low 358 mg
  • Continuous 480 mg (160 mg/d), bolus 592 mg (~200 mg/d)

Results

At 72h

• Primary efficacy outcome: Global assessment of symptoms (serial 0-100 visual analogue scale measurements tallied using area under the curve [AUC] from baseline to 72h, HIGHER=better)
  • High 4430, low 4171 (p=0.06)
  • Continuous 4373, bolus 4236 (p=0.47)
• Dyspnea AUC (higher=better)
  • High 4668, low 4478 (p=0.04)
  • Continuous 4699, bolus 4456 (p=0.36)
• Free from congestion (JVP <8 cm [<3 cm ASA], no orthopnea & trace/np peripheral edema)
  • High 18, low 11 (p=0.09)
  • Continuous 15%, bolus 14% (p=0.78)
• Wt change (kg)
  • High -3.9, low -2.7 (p=0.01)
  • Continuous -3.6, bolus -3.0 (p=0.20)
• Primary safety outcome: Change in SCr (umol/L) from baseline to 72h
  • High +7.1, low +3.5 (p=0.21)
  • Continuous +6.2, bolus +4.4 (p=0.45)
• SCr increase >26 umol/L
  • High 23%, low 14% (p=0.04)
  • Continuous 19%, bolus 17% (p=0.64)

At 60 days

• Serious adverse event
  • High 38%, low 50% (p=0.03)
  • Continuous 44%, bolus 44% (p=0.92)
• Composite of death, hospitalization or ED visit: 42% overall, no difference between groups

No difference between groups in median length of stay (5 days for all)

Generalizability

• Included a mix of HFrEF & HFpEF patients at high risk of HF hospitalization with moderate to high home doses of loop diuretics, a reasonable proportion of whom were receiving good HF medical therapy
• Outcomes were clinically important and easily measurable and translatable to practice

Internal validity

• Low risk of bias
  • 2x2 factorial randomization using permuted blocks
  • Allocation concealed
  • Double-blind, dummy-dummy design (saline placebos with identical appearance)
  • ITT analysis
  • Threshold for significance p<0.025 for coprimary outcomes (global assessment of wellbeing & change in SCr from baseline to 72h) 

ACE inhibitors & ARBs in HFpEF

CHARM-Preserved: Yusuf S, et al. Effects of candesartan in patients with chronic heart failure and preserved left-ventricular ejection fraction: the CHARM-Preserved trial. Lancet 2003;362:777-81.

I-PRESERVE: Massie BM, et al. Irbesartan in patients with heart failure and preserved ejection fraction. N Engl J Med 2008;359:2456-67.

PEP-CHF: The perindopril in elderly people with chronic heart failure (PEP-CHF) study. Eur Heart J 2006;27:2338-45.

Bottom-line: In patients with HFpEF & well-controlled hypertension, ACE inhibitors and ARBs do not reduce the risk of hospitalization or death.

However, since uncontrolled hypertension is one of the predominant causes of HFpEF and an important risk factor for HF progression, most patients with HFpEF will end up receiving an ACEI/ARB anyway to control BP.

 

Patients & Generalizability

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These trials generally enrolled older individuals with clinical HF and a LVEF >40-45%. Notably, these trials excluded multiple conditions that may be classified as "HFpEF", namely valvular heart diseases such as aortic stenosis, pericardial disease and certain cardiomyopathies.

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Due to the exclusion criteria noted above, most of the cases of HFpEF in these trials were caused by hypertension (I-PRESERVE, PEP-CHF) or ischemia (CHARM-Preserved). it is thus worth mentioning that BP was well-controlled on average at baseline in all of these trials.

Interventions

• I: ACE inhibitor or ARB
  • CHARM-Preserved: Initially, candesartan 4-8 mg PO once daily, doubled q2 weeks to target 32 mg PO daily by week 6
    • At 6 months: 67% on target dose
  • I-PRESERVE: Initially, irbesartan 75 mg PO once daily, doubled q1-2 weeks to target 300 mg PO daily
    • 88% achieved target dose
  • PEP-CHF: Initially, perindopril 2 mg PO once daily, increased to 4 mg PO daily after 2 weeks
    • ~90% on 4 mg daily at 1 year
• C: Matching placebo

Results

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Internal validity

• All 3 trials are randomized, allocation-concealed, double-blind trials with loss-to-follow-up <2% and intention to treat analysis
• Other considerations:
  • I-PRESERVE employed 1 to 2-week single-blind placebo run-in phase. Patients that remained clinically stable in this phase were randomized
  • PEP-CHF: Trial recruitment stopped early due to expected futility

Other studies

• Meta-analysis of 13 RCTs of RAAS inhibition (including ACE inhibitors, ARBs and mineralocorticoid antagonists) in HFpEF (Herz 2016;41:76-86): When all pooled together,
  • No statistically significant difference in
    • Hospitalizations: HR 0.99 (0.96-1.03)
    • CV death: HR 0.98 (0.89-1.09)
    • Death: HR 0.99 (0.92-1.07)
    • 6-minute walk test distance
  • Statistically significant reduction in HF hospitalization (HR 0.89, 0.82-0.97), though this was driven by TOPCAT trial of mineralocorticoid antagonists. The lack of a reduction on death or all-cause hospitalization suggests that the reduction in HF-related hospitalization is offset by an increase in other events (e.g. syncope or falls from hypotension, hyperkalemia).