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Elevated triglycerides and non-high-density lipoprotein cholesterol (HDL-C) are risk factors for atherosclerotic cardiovascular disease (ASCVD). ARO-ANG3 is an RNA interference therapy that targets angiopoietin-like protein 3 (ANGPTL3), a regulator of lipoprotein metabolism. This first-in-human, phase 1, randomized, placebo-controlled, open-label trial investigated single and repeat ARO-ANG3 doses in four cohorts of fifty-two healthy participants and one cohort of nine participants with hepatic steatosis, part of a basket trial. Safety (primary objective) and pharmacokinetics (in healthy participants) and pharmacodynamics (secondary objectives) of ARO-ANG3 were evaluated. ARO-ANG3 was generally well tolerated, with similar frequencies of treatment-emergent adverse events in active and placebo groups. Systemic absorption of ARO-ANG3 in healthy participants was rapid and sustained, with a mean Tmaxof 6.0–10.5 h and clearance from plasma within 24–48 h after dosing with a mean t½of 3.9–6.6 h. In healthy participants, ARO-ANG3 treatment reduced ANGPTL3 (mean −45% to −78%) 85 days after dose. Reductions in triglyceride (median −34% to −54%) and non-HDL-C (mean −18% to −29%) (exploratory endpoints) concentrations occurred with the three highest doses. These early-phase data support ANGPTL3 as a potential therapeutic target for ASCVD treatment. ClinicalTrials.gov identifier: NCT03747224

Compelling evidence supports a causal role for lipoprotein(a) (Lp(a)) in cardiovascular disease. No pharmacotherapies directly targeting Lp(a) are currently available for clinical use. Here we report the discovery and development of olpasiran, a first-in-class, synthetic, double-stranded, N-acetylgalactosamine-conjugated small interfering RNA (siRNA) designed to directly inhibit LPAmessenger RNA translation in hepatocytes and potently reduce plasma Lp(a) concentration. Olpasiran reduced Lp(a) concentrations in transgenic mice and cynomolgus monkeys in a dose-responsive manner, achieving up to over 80% reduction from baseline for 5–8 weeks after administration of a single dose. In a phase 1 dose-escalation trial of olpasiran (ClinicalTrials.gov: NCT03626662), the primary outcome was safety and tolerability, and the secondary outcomes were the change in Lp(a) concentrations and olpasiran pharmacokinetic parameters. Participants tolerated single doses of olpasiran well and experienced a 71–97% reduction in Lp(a) concentration with effects persisting for several months after administration of doses of 9 mg or higher. Serum concentrations of olpasiran increased approximately dose proportionally. Collectively, these results validate the approach of using hepatocyte-targeted siRNA to potently lower Lp(a) in individuals with elevated plasma Lp(a) concentration.

Over 30 different mutations have now been identified in MAPt that cause frontotemporal dementia (FTD). However, there are several families with FTD that show definite linkage to the region on chromosome 17 that contains MAPt, in which no mutation(s) has been identified. Although these families could have a complex mutation of the MAPt locus that has evaded detection it is also possible that another gene in this region is associated with FTD. This possibility is supported by neuropathological findings in these families, which consist of neuronal inclusions that are immunoreactive for ubiquitin (ub-ir) but not for tau. In addition to neuronal cytoplasmic inclusions, several chromosome 17-linked families are reported to have ub-ir neuronal intranuclear inclusions (NII); a finding which is uncommon in sporadic FTD. Here, we describe detailed clinical and neuropathological findings in a new large, multigenerational family with autosomal dominant FTD and autopsy proven tau-negative, ub-ir neuronal cytoplasmic and intranuclear inclusions. We have demonstrated that this family is linked to a 19.06 cM region of chromosome 17q21 with a maximum multipoint LOD score of 3.911 containing MAPt. By combining the results of our genetic analysis with those previously published for other families with similar pathology, we have further refined the minimal region to a 3.53 cM region of chromosome 17q21. We did not identify point mutations in MAPt by direct sequencing or any gross MAPt gene alterations using fluorescent in situ hybridization. In addition, tau protein extracted from members of this family was unremarkable in size and quantity as assessed by western blotting. Neuropathological characterization of the ub-ir NII in this family shows that they are positive for promyelocytic leukaemia protein (PML) and SUMO-1 that suggests that these inclusions form in the nuclear body and suggests a possible mechanism of neurodegeneration in tau-negative FTD linked to chromosome 17q21.

Background:Familial chylomicronemia syndrome (FCS) is an ultrarare condition caused by biallelic pathogenic DNA variants in lipolysis-associated genes, resulting in severe hypertriglyceridemia (HTG) and associated with high risk of acute pancreatitis with few therapeutic options. In a 16-week Phase 1 study (NCT03783377), subcutaneously administered ARO-APOC3 reduced serum apolipoprotein C3 (APOC3) and TG in healthy volunteers and participants (pts) with HTG and was well tolerated.Purpose:To report on the safety/pharmacodynamic (PD) effects of ARO-APOC3 in both FCS pts with biallelic pathogenic variants and pts with severely elevated TG at screening (>880 mg/dL) but without biallelic pathogenic variants (chylomicronemia (MCM)).Methods:Four genetically confirmed FCS pts received 50 mg ARO-APOC3 and 26 MCM pts received 10, 25, 50, or 100 mg ARO-APOC3 on Days 1 and 29. Since similar PD responses were observed among MCM pts, results were pooled across dose levels. Safety and PD responses were examined. Maximal mean/median changes from baseline for APOC3, TG, non-HDL-C, and HDL-C were reported.Results:Baseline/demographics were comparable between groups, except for mean BMI (22.1 [FCS] and 30.5 [MCM] kg/m2), and mean baseline HDL-C , which were lower in FCS pts (Table 1) (p<0.0001 for both). Mean APOC3 was reduced by 98% and 96% in FCS and MCM pts, respectively. Both groups also showed similar maximum median reductions in TG of 91% and 90%, respectively. Similar to the full study, non-HDL-C was reduced and HDL-C increased with treatment in both groups (Table 1). AEs were similar between groups, suggesting a comparable safety profile.Conclusions:In patients with severe HTG, ARO-APOC3 was safe, and consistently decreased APOC3, TG, and non-HDL-C, and increased HDL-C, regardless of underlying genetic cause of HTG, and may represent a promising RNAi therapeutic for the treatment of severe HTG.