Viney, Nicholas J.

BACKGROUND: Transthyretin amyloidosis with cardiomyopathy is a progressive, fatal disease characterized by deposition of extracellular misfolded transthyretin (TTR) in the myocardium. Eplontersen is an N-acetylgalactosamine ligand–conjugated antisense oligonucleotide targeting hepatocyte TTR messenger RNA to reduce the production of circulating TTR. METHODS: CARDIO-TTRansform is a Phase 3, randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of eplontersen in transthyretin amyloidosis with cardiomyopathy. Key inclusion criteria include histological evidence of amyloid deposits or grade 2 to 3 cardiac uptake on cardiac scintigraphy in the absence of plasma cell dyscrasia, New York Heart Association class I–III, and end-diastolic interventricular septum thickness >12 millimeters. Participants were randomized 1:1 to receive eplontersen 45 mg or placebo, administered subcutaneously every 4 weeks for up to 140 weeks, followed by a 20-week post-treatment evaluation period or open-label extension. Participants received locally available standard of care, including unrestricted use of TTR stabilizers. The primary end point is a composite of cardiovascular mortality and recurrent clinical cardiovascular events through 140 weeks. Secondary end points, in order of testing hierarchy, include changes from baseline in 6-minute walk distance and Kansas City Cardiomyopathy Questionnaire overall summary score, recurrent cardiovascular events, all-cause mortality, the primary end point in the patient subgroup receiving stabilizers at baseline, and cardiovascular mortality. Echocardiography was performed in all participants, with cardiovascular magnetic resonance imaging and technetium scintigraphy in a subset. CONCLUSIONS: CARDIO-TTRansform is fully enrolled, with 1432 randomized participants who were dosed with study drug or placebo. As the largest transthyretin amyloidosis with cardiomyopathy study to date, it will evaluate whether eplontersen improves cardiovascular outcomes in patients receiving locally available standard of care, including TTR stabilizers. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04136171. URL: http://ClinicalTrialsRegister.eu ; Unique identifier: EudraCT number 2019-002835-27.

Importance Transthyretin gene silencing is an emerging treatment strategy for hereditary transthyretin (ATTRv) amyloidosis. Objective To evaluate eplontersen, an investigational ligand-conjugated antisense oligonucleotide, in ATTRv polyneuropathy. Design, Setting, and Participants NEURO-TTRansform was an open-label, single-group, phase 3 trial conducted at 40 sites across 15 countries (December 2019-April 2023) in 168 adults with Coutinho stage 1 or 2 ATTRv polyneuropathy, Neuropathy Impairment Score 10-130, and a documented TTR variant. Patients treated with placebo from NEURO-TTR ( NCT01737398 ; March 2013–November 2017), an inotersen trial with similar eligibility criteria and end points, served as a historical placebo (“placebo”) group. Interventions Subcutaneous eplontersen (45 mg every 4 weeks; n = 144); a small reference group received subcutaneous inotersen (300 mg weekly; n = 24); subcutaneous placebo weekly (in NEURO-TTR; n = 60). Main Outcomes and Measures Primary efficacy end points at week 65/66 were changes from baseline in serum transthyretin concentration, modified Neuropathy Impairment Score +7 (mNIS+7) composite score (scoring range, –22.3 to 346.3; higher scores indicate poorer function), and Norfolk Quality of Life Questionnaire–Diabetic Neuropathy (Norfolk QoL-DN) total score (scoring range, –4 to 136; higher scores indicate poorer quality of life). Analyses of efficacy end points were based on a mixed-effects model with repeated measures adjusted by propensity score weights. Results Among 144 eplontersen-treated patients (mean age, 53.0 years; 69% male), 136 (94.4%) completed week-66 follow-up; among 60 placebo patients (mean age, 59.5 years; 68% male), 52 (86.7%) completed week-66 follow-up. At week 65, adjusted mean percentage reduction in serum transthyretin was −81.7% with eplontersen and −11.2% with placebo (difference, −70.4% [95% CI, −75.2% to −65.7%]; P < .001). Adjusted mean change from baseline to week 66 was lower (better) with eplontersen vs placebo for mNIS+7 composite score (0.3 vs 25.1; difference, −24.8 [95% CI, −31.0 to −18.6; P < .001) and for Norfolk QoL-DN (−5.5 vs 14.2; difference, −19.7 [95% CI, −25.6 to −13.8]; P < .001). Adverse events by week 66 that led to study drug discontinuation occurred in 6 patients (4%) in the eplontersen group vs 2 (3%) in the placebo group. Through week 66, there were 2 deaths in the eplontersen group consistent with known disease-related sequelae (cardiac arrhythmia; intracerebral hemorrhage); there were no deaths in the placebo group. Conclusions and Relevance In patients with ATTRv polyneuropathy, the eplontersen treatment group demonstrated changes consistent with significantly lowered serum transthyretin concentration, less neuropathy impairment, and better quality of life compared with a historical placebo. Trial Registration ClinicalTrials.gov Identifier: NCT04136184 ; EU Clinical Trials Register: EudraCT 2019-001698-10

Background: Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a life-threatening, irreversible condition, which can lead to heart failure (HF) and, ultimately, heart transplant or death. Despite the recent approval in United States of a TTR stabilizer (VYNDAQEL®-tafamidis meglumine;VYNDAMAX™-tafamidis) for the treatment of ATTR-CM, disease progression still occurs. This study aims to determine if treatment with AKCEA-TTR-LRx (ION-682884), an antisense oligonucleotide (ASO), is safe and superior to placebo in reducing the risk of cardiovascular (CV) death or CV clinical events in patients with hereditary (hATTR-CM) or wild-type ATTR-CM (wtATTR-CM). Study Design and Methods: AKCEA-TTR-LRx (ION-682884) is a follow-on compound that incorporates the Ligand-Conjugated Antisense (LICA) technology; in this case, a triantennary N-acetyl galactosamine (GalNAc) moiety which targets the asialoglycoprotein receptors (ASGPR) expressed abundantly on the hepatocyte cell surface. In comparison to inotersen, its parent compound, ION-682884 requires a lower dose and frequency of administration (27-fold smaller; 45mg SC Q4W) to achieve a similar reduction in ATTR, providing greater patient convenience. ION-682884-CS2 (EudraCT No: 2019-002835-27) is a Phase 3 global, double-blind, randomized, placebo-controlled study assessing the efficacy and safety of AKCEA-TTR-LRx (ION-682884) in hATTR-CM or wtATTR-CM patients receiving available background standard of care (SoC) therapy. Approximately 750 patients with a history of HF due to ATTR-CM will be randomized 1:1 to receive AKCEA-TTR-LRx (ION-682884) or placebo administered by subcutaneous injection once every 4 weeks. The main inclusion criteria include confirmed diagnosis of ATTR-CM by tissue biopsy or positive PYP/DPD scan, end-diastolic interventricular septum thickness of >12mm, NT-proBNP >600 pg/mL, NYHA class I-III and 6-minute walk distance (6MWD) >150 m. The main exclusion criteria include estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73m2, platelet count below the low limit of normality and urine protein/creatinine ratio (UPCR) ≥ 1000 mg/g. Patients are allowed to concomitantly receive tafamidis/tafamidis meglumine as SoC for ATTR-CM, if locally approved and available, per physician's discretion. The study consists of a 120-week Treatment Period and a 20-week Post-Treatment Evaluation Period. During each study visit, subjects will undergo laboratory tests, cardiac assessments (echocardiography), and functional evaluations. Patient-reported outcomes (PRO) will also be collected. Primary efficacy endpoint is the composite of CV mortality and frequency of CV clinical events (HF-related urgent visits requiring administration of IV diuretics and/or CV-related hospitalizations) at Week 120 study visit, analyzed by the Finkelstein-Shoenfeld method. This test is based on the principle of each patient in the study being compared with every other patient in a pairwise manner in hierarchical fashion. Secondary endpoints include the change from baseline in the 6MWD, Kansas City Cardiomyopathy Questionnaire score, rate of CV mortality, CV clinical events, and all-cause of mortality at Week 120. Additional exploratory endpoints include a change from baseline in cardiac imaging parameters, renal function, biomarkers, and PROs questionnaires and disease scores. An interim analysis on change from baseline in 6MWD is also planned at Week 60. All deaths and CV clinical events will be adjudicated by an independent, blinded Clinical Adjudication Committee, using predefined endpoint criteria. Conclusions: Despite recent advances, there is still a need for more efficacious, safe and convenient treatment options for ATTR-CM. The ION-682884-CS2 is a large Phase 3 trial designed to evaluate the clinical efficacy and safety of AKCEA-TTR-LRx (ION-682884) compared to placebo for the treatment of ATTR-CM. Figure Disclosures Falk: Ionis Pharmaceuticals: Consultancy. Gertz:Ionis/Akcea: Consultancy; Alnylam: Consultancy; Proclara: Membership on an entity's Board of Directors or advisory committees; Prothena Biosciences Inc: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Spectrum: Consultancy, Research Funding; Annexon: Consultancy; Appellis: Consultancy; Amgen: Consultancy; Medscape: Consultancy, Speakers Bureau; Physicians Education Resource: Consultancy; Abbvie: Other: personal fees for Data Safety Monitoring board; Research to Practice: Consultancy; Teva: Speakers Bureau; Johnson and Johnson: Speakers Bureau; DAVA oncology: Speakers Bureau; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; i3Health: Other: Development of educational programs and materials; Springer Publishing: Patents & Royalties; Amyloidosis Foundation: Research Funding; International Waldenstrom Foundation: Research Funding. Benson:Ionis Pharmaceuticals: Research Funding. Buchele:Ionis Pharmaceuticals: Employment. Brambatti:Ionis Pharmaceuticals: Employment. Tsimikas:Ionis Pharmaceuticals: Employment. Viney:Ionis Pharmaceuticals: Employment. Tai:Ionis Pharmaceuticals: Employment. Monteiro:Ionis Pharmaceuticals: Employment. Yang:Ionis Pharmaceuticals: Employment. O'Dea:Akcea Therapeutics: Employment. Karwatowska-Prokopczuk:Akcea Therapeutics: Employment. Schneider:Ionis Pharmaceuticals: Employment. Geary:Ionis Pharmaceuticals: Employment. Monia:Ionis Pharmaceuticals: Employment.