Acoramidis

Acoramidis (AG10) is a potent, selective, orally bioavailable small-molecule kinetic stabilizer of the transthyretin (TTR) tetramer, approved in the United States, European Union, United Kingdom, and Japan for the treatment of cardiomyopathy caused by wild-type or hereditary transthyretin-mediated amyloidosis (ATTR-CM). The compound was rationally designed to replicate the molecular mechanism of the naturally occurring T119M variant of TTR, a protective mutation that stabilizes the tetramer against the rate-limiting dissociation step that initiates amyloid fibril formation. Structurally, acoramidis is a 3,5-dimethylpyrazole linked through a propyloxy tether to a 4-fluorobenzoic acid; the pyrazole ring forms two hydrogen bonds with serine 117 and serine 117 prime residues at the floor of the thyroxine binding pocket, replicating the inter-dimer contact created by the threonine-to-methionine substitution in T119M carriers. This enthalpy-driven binding mechanism (binding enthalpy of negative 13.6 kilocalories per mole, compared to negative 5.0 kilocalories per mole for tafamidis) underpins the high selectivity of acoramidis for TTR over albumin and its capacity to achieve greater than 90 percent tetramer stabilization across the entire dosing interval at steady state. The clinical development program for acoramidis established pharmacokinetic parameters favorable for twice-daily oral dosing: rapid absorption (time to peak concentration less than one hour), terminal elimination half-life of approximately 25 hours, metabolism principally by UGT-mediated glucuronidation rather than cytochrome P450 enzymes, and renal elimination of conjugated metabolites. The pivotal Phase 3 ATTRibute-CM trial randomized 632 patients with wild-type or hereditary ATTR-CM to acoramidis 800 milligrams (as the hydrochloride salt) in the published literature or placebo for 30 months. On the primary hierarchical endpoint (a four-component analysis of all-cause mortality, cardiovascular-related hospitalization, NT-proBNP change, and six-minute walk distance), acoramidis demonstrated a win ratio of 1.8 (95 percent confidence interval 1.4 to 2.2; P less than 0.001). The time-to-event composite of all-cause mortality or first cardiovascular hospitalization favored acoramidis with a hazard ratio of 0.64 (95 percent confidence interval 0.50 to 0.83; P equals 0.0008), with Kaplan-Meier curves separating at three months and benefit sustained through 42 months of follow-up in the open-label extension. A cardiac magnetic resonance substudy demonstrated stabilization of left ventricular mass and improvement of ejection fraction in the acoramidis arm relative to progressive deterioration in placebo recipients. The adverse event profile was similar to placebo; diarrhea (11.6 versus 7.6 percent) and gout (10.9 versus 8.1 percent) were the most frequent treatment-emergent events occurring at higher rates with acoramidis. This monograph reviews the chemistry, synthesis, and rational design of acoramidis; the enthalpy-driven TTR stabilization mechanism characterized through isothermal titration calorimetry and X-ray crystallography; the complete human pharmacokinetic profile; preclinical pharmacology in rodent and canine models; the clinical evidence base from Phase 1 through Phase 3 and the open-label extension; sourcing and quality considerations for research applications; reconstitution and handling; metabolic and pharmacodynamic interactions; the adverse event and safety profile; and a comparative assessment of five transthyretin-directed therapies (tafamidis, diflunisal, patisiran, vutrisiran, and eplontersen) against acoramidis on five competency standards. Acoramidis is a prescription medicine in its approved jurisdictions and is available as a research-grade preparation for investigational applications outside the approved indication. Investigators should obtain analytical confirmation of identity and purity on every research-grade lot.