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Transthyretin-mediated amyloidosis (ATTR) is a rare, under-recognized, progressively debilitating, fatal disease caused by the aggregation and extracellular deposition of amyloid transthyretin (TTR) fibrils in multiple organs and tissues throughout the body. TTR is predominantly synthesized by the liver and normally circulates as a homotetramer, while misfolded monomers aggregate to form amyloid fibrils. One strategy to treat ATTR amyloidosis is to reduce the amount of TTR produced by the liver using drugs that directly target the TTR mRNA or gene. This narrative review focuses on how TTR gene silencing tools act to reduce TTR production, describing strategies for improved targeted delivery of these agents to hepatocytes where TTR is preferentially expressed. Antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs), termed RNA silencers, cause selective degradation of TTR mRNA, while a TTR gene editing tool reduces TTR expression by introducing nonsense mutations into the TTR gene. Two strategies to facilitate tissue-specific delivery of these nucleic acid-based drugs employ endogenous receptors expressed by hepatocytes. Lipid nanoparticles (LNPs) that recruit apolipoprotein E support low-density lipoprotein receptor-mediated uptake of unconjugated siRNA and are now used for CRISPR gene editing tools. Additionally, conjugating N-acetylgalactosamine (GalNAc) moieties to ASOs or siRNAs facilitates receptor-mediated uptake by the asialoglycoprotein receptor. In summary, ATTR is a progressive disease with various clinical manifestations due to TTR aggregation, deposition, and amyloid formation. Receptor-targeted ligands (eg, GalNAc) and nanoparticle encapsulation (eg, LNPs) are technologies to deliver ASOs, siRNAs, and gene editing tools to hepatocytes, the primary location of TTR synthesis.

Introduction AKCEA-TTR-LRx is a ligand-conjugated antisense (LICA) drug in development for the treatment of hereditary transthyretin amyloidosis (hATTR), a fatal disease caused by mutations in the transthyretin (TTR) gene. AKCEA-TTR-LRx shares the same nucleotide sequence as inotersen, an antisense medicine approved for use in hATTR polyneuropathy (hATTR-PN). Unlike inotersen, AKCEA-TTR-LRx is conjugated to a triantennary N-acetylgalactosamine moiety that supports receptor-mediated uptake by hepatocytes, the primary source of circulating TTR. This advanced design increases drug potency to allow for lower and less frequent dosing. The NEURO-TTRansform study will investigate whether AKCEA-TTR-LRx is safe and efficacious, with the aim of improving neurologic function and quality of life in hATTR-PN patients. Methods/Design Approximately 140 adults with stage 1 (independent ambulation) or 2 (requires ambulatory support) hATTR-PN are anticipated to enroll in this multicenter, open-label, randomized, phase 3 study. Patients will be assigned 6:1 to AKCEA-TTR-LRx 45 mg subcutaneously every 4 weeks or inotersen 300 mg once weekly until the prespecified week 35 interim efficacy analysis, after which patients receiving inotersen will receive AKCEA-TTR-LRx 45 mg subcutaneously every 4 weeks. All patients will then receive AKCEA-TTR-LRx through the remainder of the study treatment period. The final efficacy analysis at week 66 will compare the AKCEA-TTR-LRx arm with the historical placebo arm from the phase 3 trial of inotersen (NEURO-TTR). The primary outcome measures are between-group differences in the change from baseline in serum TTR, modified Neuropathy Impairment Score + 7, and Norfolk Quality of Life—Diabetic Neuropathy questionnaire. Conclusion NEURO-TTRansform is designed to determine whether targeted delivery of AKCEA-TTR-LRx to hepatocytes with lower and less frequent doses will translate into clinical and quality-of-life benefits for patients with hATTR-PN. Trial Registration The study is registered at ClinicalTrials.gov (NCT04136184) and EudraCT (2019-001698-10). Supplementary Information The online version contains supplementary material available at 10.1007/s40120-021-00235-6., Plain Language Summary Hereditary transthyretin amyloidosis with peripheral neuropathy (hATTR-PN for short) is a rare inherited condition.In hATTR-PN, a protein called transthyretin (TTR for short) builds up and damages nerves throughout the body.This neuropathy causes symptoms such as weakness, loss of sensation, and pain.Currently available medicines can slow disease progression, but researchers are looking for more effective treatments with fewer side effects.AKCEA-TTR-LRx is an investigational treatment for hATTR-PN.AKCEA-TTR-LRx prevents the liver from making TTR, reducing the amount that causes disease progression.It is similar to an existing treatment called inotersen, but designed for better delivery to the liver and is more potent.This article describes the NEURO-TTRansform study that will evaluate how effective AKCEA-TTR-LRx is for treating hATTR-PN.Around 140 adults with hATTR-PN from the USA, Canada, and Europe will be able to take part in this study.The study treatment period will be 85 weeks long. People will receive injections underneath the skin of either:AKCEA-TTR-LRx every 4 weeks, orInotersen once a week for 35 weeks, followed by a switch to AKCEA-TTR-LRx every 4 weeks.People may continue to receive AKCEA-TTR-LRx after the study treatment period ends.In this study, researchers will compare results from people who received AKCEA-TTR-LRx to results from people who received no active ingredients (called placebo) in a similar study (called NEURO-TTR).Researchers will measure the differences in peoples’:Neuropathy symptoms.Quality of life.TTR protein levels in the blood. Supplementary Information The online version contains supplementary material available at 10.1007/s40120-021-00235-6.

Objectives There has been limited success in achieving integration of patient-reported outcomes (PROs) in clinical trials. We describe how stakeholders envision a solution to this challenge. Methods Stakeholders from academia, industry, non-profits, insurers, clinicians, and the Food and Drug Administration convened at a Think Tank meeting funded by the Duke Clinical Research Institute to discuss the challenges of incorporating PROs into clinical trials and how to address those challenges. Using examples from cardiovascular trials, this article describes a potential path forward with a focus on applications in the United States. Results Think Tank members identified one key challenge: a common understanding of the level of evidence that is necessary to support patient-reported outcome measures (PROMs) in trials. Think Tank participants discussed the possibility of creating general evidentiary standards depending upon contextual factors, but such guidelines could not be feasibly developed because many contextual factors are at play. The attendees posited that a more informative approach to PROM evidentiary standards would be to develop validity arguments akin to courtroom briefs, which would emphasize a compelling rationale (interpretation/use argument) to support a PROM within a specific context. Participants envisioned a future in which validity arguments would be publicly available via a repository, which would be indexed by contextual factors, clinical populations, and types of claims. Conclusions A publicly available repository would help stakeholders better understand what a community believes constitutes compelling support for a specific PROM in a trial. Our proposed strategy is expected to facilitate the incorporation of PROMs into cardiovascular clinical trials and trials in general.

AimsAmyloidogenic transthyretin (ATTR) amyloidosis is a fatal disease characterized by progressive cardiomyopathy and/or polyneuropathy. AKCEA-TTR-LRx (ION-682884) is a ligand-conjugated antisense drug designed for receptor-mediated uptake by hepatocytes, the primary source of circulating transthyretin (TTR). Enhanced delivery of the antisense pharmacophore is expected to increase drug potency and support lower, less frequent dosing in treatment.Methods and resultsAKCEA-TTR-LRx demonstrated an approximate 50-fold and 30-fold increase in potency compared with the unconjugated antisense drug, inotersen, in human hepatocyte cell culture and mice expressing a mutated human genomic TTR sequence, respectively. This increase in potency was supported by a preferential distribution of AKCEA-TTR-LRx to liver hepatocytes in the transgenic hTTR mouse model. A randomized, placebo-controlled, phase 1 study was conducted to evaluate AKCEA-TTR-LRx in healthy volunteers (ClinicalTrials.gov: NCT03728634). Eligible participants were assigned to one of three multiple-dose cohorts (45, 60, and 90mg) or a single-dose cohort (120mg), and then randomized 10:2 (active:placebo) to receive a total of 4 SC doses (Day 1, 29, 57, and 85) in the multiple-dose cohorts or 1 SC dose in the single-dose cohort. The primary endpoint was safety and tolerability; pharmacokinetics and pharmacodynamics were secondary endpoints. All randomized participants completed treatment. No serious adverse events were reported. In the multiple-dose cohorts, AKCEA-TTR-LRx reduced TTR levels from baseline to 2weeks after the last dose of 45, 60, or 90mg by a mean (SD) of -85.7% (8.0), -90.5% (7.4), and -93.8% (3.4), compared with -5.9% (14.0) for pooled placebo (P&nbsp

Background Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a fatal condition, leading to heart failure (HF) and ultimately death. ATTR-CM is caused by misfolding and aggregation of transthyretin (TTR), a protein produced by the liver. Depending on the presence or absence of a destabilizing mutation in the TTR gene, the disease can be classified as hereditary ATTR-CM (hATTR-CM) or wild-type ATTR-CM (wtATTR-CM), respectively. Despite the treatment with a TTR stabilizer, tafamidis, recently approved in the United States for the treatment of ATTR-CM, disease progression still occurs. AKCEA-TTR-LRX (ION-682884) is an antisense oligonucleotide (ASO) that inhibits the production of TTR. It has a similar design and sequence as inotersen (the parent compound), but is conjugated to a triantennary N-acetyl galactosamine (GalNAc3) moiety for selective receptor-mediated delivery to hepatocytes, the principal source of systemically circulating TTR. This delivery approach has yielded an up to 30-fold increase in potency and improved the safety and tolerability profiles of ASOs in human clinical trials. Conjugation of this ligand allows the use of a lower dose to achieve improved pharmacodynamic results. In a phase 1, randomized, placebo-controlled study, AKCEA-TTR-LRX given at a 45 mg, 60 mg or 90 mg dose, by subcutaneous (SC) injection every four weeks in 36 healthy volunteers achieved a mean pre-steady state reduction in serum TTR of 86%, 91% and 94%, respectively, compared to baseline. The dosage regimen of 45 mg SC every four weeks (27-fold lower exposure vs the inotersen dose in NEURO-TTR trial) was chosen for the pivotal phase 3 study. Methods CARDIO-TTRansform (ClinicalTrials.gov NCT04136171) is a Phase 3 global, double-blind, randomized, placebo-controlled study assessing the efficacy and safety of AKCEA-TTR-L Rx in hATTR-CM or wtATTR-CM patients receiving available background standard of care (SoC) therapy. Approximately 750 patients around the world with a history of HF due to ATTR-CM will be randomized 1:1 to receive either AKCEA-TTR-LRx 45 mg or placebo administered by SC injection once every 4 weeks. Key inclusion criteria include diagnosis of ATTR-CM by biopsy or positive PYP/DPD/HMDP scan, interventricular septum thickness >12mm, NT-proBNP > 600 pg/mL, NYHA class I-III and 6-minute walk distance (6MWD) >150 m. Key exclusion criteria include, platelet count = 750 mg/g. Concomitant treatment with tafamidis as SoC for ATTR-CM is allowed. The study consists of a 120-week Treatment Period. Primary efficacy endpoint is the composite of cardiovascular (CV) mortality and recurrent CV clinical events at Week 120 study visit using the Andersen-Gill method. Secondary endpoints include the change from baseline in the 6MWD, KCCQ score, CV clinical events, CV death and all-cause of mortality at Week 120. Conclusions Despite recent advances, additional efficacious, safe and convenient treatment options for ATTR-CM are needed. The CARDIO-TTRansform trial is a large Phase 3 trial designed to evaluate the clinical efficacy and safety of AKCEA-TTR-LRx compared to placebo in patients with ATTR-CM receiving available SoC therapy.

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.

Atrial fibrillation/ flutter (AF) is a common comorbidity in patients with heart failure (HF). We examined the influence of AF on the response to the selective cardiac myosin activator, omecamtiv mecarbil (OM), in patients with HFrEF. COSMIC-HF (NCT 01786512) was a Phase 2 multicenter, randomized