Effects of tafamidis on transthyretin stabilization and clinical outcomes in patients with non-Val30Met transthyretin amyloidosis

This phase II, open-label, single-treatment arm study evaluated the pharmacodynamics, efficacy, and safety of tafamidis in patients with non-Val30Met transthyretin (TTR) amyloidosis. Twenty-one patients with eight different non-Val30Met mutations received 20 mg QD of tafamidis meglumine for 12 months. The primary outcome, TTR stabilization at Week 6, was achieved in 18 (94.7 %) of 19 patients with evaluable data. TTR was stabilized in 100 % of patients with non-missing data at Months 6 (n = 18) and 12 (n = 17). Exploratory efficacy measures demonstrated some worsening of neurological function. However, health-related quality of life, cardiac biomarker N-terminal pro-hormone brain natriuretic peptide, echocardiographic parameters, and modified body mass index did not demonstrate clinically relevant worsening during the 12 months of treatment. Tafamidis was well tolerated. In conclusion, our findings suggest that tafamidis 20 mg QD effectively stabilized TTR associated with several non-Val30Met variants

A possible role for miRNA silencing in disease phenotype variation in Swedish transthyretin V30M carriers

Our results are the first to show the presence of a 3'UTR polymorphism on the V30M haplotype in Swedish carriers, which can serve as a miRNA binding site potentially leading to down-regulated expression from the mutated TTR allele. This finding may be related to the low penetrance and high age at onset of the disease observed in the Swedish patient population

Genotype and Phenotype of Transthyretin Cardiac Amyloidosis: THAOS (Transthyretin Amyloid Outcome Survey)

Background Transthyretin amyloidosis (ATTR) is a heterogeneous disorder with multiorgan involvement and a genetic or nongenetic basis. Objectives The goal of this study was to describe ATTR in the United States by using data from the THAOS (Transthyretin Amyloidosis Outcomes Survey) registry. Methods Demographic, clinical, and genetic features of patients enrolled in the THAOS registry in the United States (n = 390) were compared with data from patients from other regions of the world (ROW) (n = 2,140). The focus was on the phenotypic expression and survival in the majority of U.S. subjects with valine-to-isoleucine substitution at position 122 (Val122Ile) (n = 91) and wild-type ATTR (n = 189). Results U.S. subjects are older (70 vs. 46 years), more often male (85.4% vs. 50.6%), and more often of African descent (25.4% vs. 0.5%) than the ROW. A significantly higher percentage of U.S. patients with ATTR amyloid seen at cardiology sites had wild-type disease than the ROW (50.5% vs. 26.2%). In the United States, 34 different mutations (n = 201) have been reported, with the most common being Val122Ile (n = 91; 45.3%) and Thr60Ala (n = 41; 20.4%). Overall, 91 (85%) of 107 patients with Val122Ile were from the United States, where Val122Ile subjects were younger and more often female and black than patients with wild-type disease, and had similar cardiac phenotype but a greater burden of neurologic symptoms (pain, numbness, tingling, and walking disability) and worse quality of life. Advancing age and lower mean arterial pressure, but not the presence of a transthyretin mutation, were independently associated with higher mortality from a multivariate analysis of survival. Conclusions In the THAOS registry, ATTR in the United States is overwhelmingly a disorder of older adult male subjects with a cardiac-predominant phenotype. Val122Ile is the most common transthyretin mutation, and neurologic phenotypic expression differs between wild-type disease and Val122Ile, but survival from enrollment in THAOS does not. (Transthyretin-Associated Amyloidoses Outcome Survey [THAOS]; NCT00628745

Inotersen treatment for patients with hereditary transthyretin amyloidosis

BACKGROUND: Hereditary transthyretin amyloidosis is caused by pathogenic single-nucleotide variants in the gene encoding transthyretin ( TTR) that induce transthyretin misfolding and systemic deposition of amyloid. Progressive amyloid accumulation leads to multiorgan dysfunction and death. Inotersen, a 2'- O-methoxyethyl-modified antisense oligonucleotide, inhibits hepatic production of transthyretin. METHODS: We conducted an international, randomized, double-blind, placebo-controlled, 15-month, phase 3 trial of inotersen in adults with stage 1 (patient is ambulatory) or stage 2 (patient is ambulatory with assistance) hereditary transthyretin amyloidosis with polyneuropathy. Patients were randomly assigned, in a 2:1 ratio, to receive weekly subcutaneous injections of inotersen (300 mg) or placebo. The primary end points were the change in the modified Neuropathy Impairment Score+7 (mNIS+7; range, -22.3 to 346.3, with higher scores indicating poorer function; minimal clinically meaningful change, 2 points) and the change in the score on the patient-reported Norfolk Quality of Life-Diabetic Neuropathy (QOL-DN) questionnaire (range, -4 to 136, with higher scores indicating poorer quality of life). A decrease in scores indicated improvement. RESULTS: A total of 172 patients (112 in the inotersen group and 60 in the placebo group) received at least one dose of a trial regimen, and 139 (81%) completed the intervention period. Both primary efficacy assessments favored inotersen: the difference in the least-squares mean change from baseline to week 66 between the two groups (inotersen minus placebo) was -19.7 points (95% confidence interval [CI], -26.4 to -13.0; P<0.001) for the mNIS+7 and -11.7 points (95% CI, -18.3 to -5.1; P<0.001) for the Norfolk QOL-DN score. These improvements were independent of disease stage, mutation type, or the presence of cardiomyopathy. There were five deaths in the inotersen group and none in the placebo group. The most frequent serious adverse events in the inotersen group were glomerulonephritis (in 3 patients [3%]) and thrombocytopenia (in 3 patients [3%]), with one death associated with one of the cases of grade 4 thrombocytopenia. Thereafter, all patients received enhanced monitoring. CONCLUSIONS: Inotersen improved the course of neurologic disease and quality of life in patients with hereditary transthyretin amyloidosis. Thrombocytopenia and glomerulonephritis were managed with enhanced monitoring. (Funded by Ionis Pharmaceuticals; NEURO-TTR ClinicalTrials.gov number, NCT01737398 .)

Patisiran, an RNAi therapeutic, for hereditary transthyretin amyloidosis

BACKGROUND Patisiran, an investigational RNA interference therapeutic agent, specifically inhibits hepatic synthesis of transthyretin. METHODS In this phase 3 trial, we randomly assigned patients with hereditary transthyretin amyloidosis with polyneuropathy, in a 2:1 ratio, to receive intravenous patisiran (0.3 mg per kilogram of body weight) or placebo once every 3 weeks. The primary end point was the change from baseline in the modified Neuropathy Impairment Score+7 (mNIS+7; range, 0 to 304, with higher scores indicating more impairment) at 18 months. Other assessments included the Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) questionnaire (range, −4 to 136, with higher scores indicating worse quality of life), 10-m walk test (with gait speed measured in meters per second), and modified body-mass index (modified BMI, defined as [weight in kilograms divided by square of height in meters]×albumin level in grams per liter; lower values indicated worse nutritional status). RESULTS A total of 225 patients underwent randomization (148 to the patisiran group and 77 to the placebo group). The mean (±SD) mNIS+7 at baseline was 80.9±41.5 in the patisiran group and 74.6±37.0 in the placebo group; the least-squares mean (±SE) change from baseline was −6.0±1.7 versus 28.0±2.6 (difference, −34.0 points; P<0.001) at 18 months. The mean (±SD) baseline Norfolk QOL-DN score was 59.6±28.2 in the patisiran group and 55.5±24.3 in the placebo group; the least-squares mean (±SE) change from baseline was −6.7±1.8 versus 14.4±2.7 (difference, −21.1 points; P<0.001) at 18 months. Patisiran also showed an effect on gait speed and modified BMI. At 18 months, the least-squares mean change from baseline in gait speed was 0.08±0.02 m per second with patisiran versus −0.24±0.04 m per second with placebo (difference, 0.31 m per second; P<0.001), and the least-squares mean change from baseline in the modified BMI was −3.7±9.6 versus −119.4±14.5 (difference, 115.7; P<0.001). Approximately 20% of the patients who received patisiran and 10% of those who received placebo had mild or moderate infusion-related reactions; the overall incidence and types of adverse events were similar in the two groups. CONCLUSIONS In this trial, patisiran improved multiple clinical manifestations of hereditary transthyretin amyloidosis