How does Atruby (acoramidis) improve heart failure in adult patients with transthyretin amyloid cardiomyopathy who have heart‑failure symptoms or elevated N‑terminal pro‑B‑type natriuretic peptide?

How Atruby (Acoramidis) Improves Heart Failure in ATTR-CM

Atruby (acoramidis) improves heart failure in transthyretin amyloid cardiomyopathy by binding with high affinity to the TTR tetramer and preventing its dissociation into toxic monomers that form amyloid deposits in the heart, thereby slowing disease progression and reducing cardiovascular death and hospitalizations. 1

Mechanism of Action

Acoramidis is a high-affinity TTR stabilizer structurally designed to mimic the naturally occurring T119M mutation that confers resistance to amyloidogenesis. 2 The drug works through the following mechanism:

• Binds selectively to the thyroxine-binding sites on tetrameric TTR protein, preventing tetramer dissociation into monomers that subsequently misfold and aggregate into amyloid fibrils 3, 4
• Achieves >90% TTR stabilization across the entire dosing interval, making it the first drug to demonstrate near-complete stabilization of TTR 4, 1
• By the end of phase II trials, all acoramidis-treated patients achieved normal serum TTR concentrations, indicating robust biochemical efficacy 3

This mechanism directly addresses the pathophysiology of ATTR-CM, where misfolded TTR protein accumulates in cardiac tissue between myocytes, causing microvascular dysfunction, myocyte injury and necrosis, impaired diastolic function, progressive ventricular wall thickening, and impaired longitudinal systolic function. 2

Clinical Efficacy on Mortality and Morbidity

In the pivotal ATTRibute-CM phase 3 trial involving 632 patients, acoramidis demonstrated statistically significant superiority over placebo on a four-step hierarchical primary outcome (P<0.001, win ratio 1.8). 1 The specific benefits include:

Mortality and Hospitalization

• Death from any cause and cardiovascular-related hospitalization together contributed more than half (58%) of the wins in pairwise comparisons 1
• While acoramidis did not achieve statistical significance for mortality reduction alone, it outperformed placebo with respect to the combined endpoint of death from any cause and cardiovascular-related hospitalization 3

Biomarker Improvement

• NT-proBNP pairwise comparisons yielded the highest ratio of wins to losses (23.3% vs. 7.0%), indicating substantial improvement in cardiac stress markers 1
• The change in NT-proBNP from baseline was significantly better with acoramidis compared to placebo 3

Functional Capacity

• Acoramidis improved the 6-minute walk distance compared to placebo, demonstrating better preservation of functional capacity 3, 1
• The Kansas City Cardiomyopathy Questionnaire-Overall Summary scores were included as key secondary outcomes, addressing quality of life 1

Safety Profile

The overall incidence of adverse events was similar between acoramidis (98.1%) and placebo (97.6%) groups, but serious adverse events were actually lower with acoramidis (54.6% vs. 64.9%). 1 This favorable safety profile is critical because:

• Treatment-emergent adverse events were comparable between groups 3
• The drug was well-tolerated throughout the 30-month trial period 1
• No unique safety signals emerged that would limit its use in the target population 3

Place in Therapy

Acoramidis is the second TTR stabilizer approved for ATTR-CM treatment, following tafamidis. 3, 2 However, its specific advantages include:

• Near-complete (>90%) TTR stabilization, compared to the partial stabilization seen with other agents 4
• Demonstrated efficacy in both wild-type and variant ATTR-CM 4, 1
• Dosing at 800 mg twice daily provides consistent stabilization across the dosing interval 1

Clinical Context and Patient Selection

Based on the trial design, acoramidis is appropriate for:

• Patients with estimated glomerular filtration rate ≥30 mL/min/1.73 m², as efficacy was assessed in this population 1
• Patients with heart failure symptoms or elevated NT-proBNP, as these were key inclusion criteria and outcome measures 1
• Both wild-type and variant ATTR-CM patients, as both subtypes were included in the pivotal trial 4, 1

Important Caveats

While acoramidis prevents further amyloid deposition, it does not reverse existing deposits—similar to other TTR stabilizers like tafamidis. 5, 6 This means:

• Earlier initiation in the disease course would theoretically provide greater benefit, though this was not specifically studied for acoramidis 5, 6
• The drug slows or halts accumulation but does not clear existing cardiac amyloid 3
• Patients should still receive appropriate heart failure management, though standard GDMT is often poorly tolerated in cardiac amyloidosis 5

The lack of head-to-head trials with tafamidis means the relative efficacy and optimal place in therapy remain unclear. 3 Each TTR stabilizer similarly decreases combined endpoints of all-cause mortality and heart failure progression when adjusted for risk factors, but direct comparison data are not available. 3