The N-Acetylgalactosamine-conjugated small interfering RNA inclisiran can be coadministered safely with atorvastatin in cynomolgus monkeys resulting in additive low-density lipoprotein cholesterol reductions.

Inclisiran, a small interfering RNA, selectively inhibits proprotein convertase subtilisin/kexin type 9 (PCSK9) synthesis in the liver and has been shown to reduce low-density lipoprotein cholesterol (LDL-C) by ≥50% in patients with hypercholesterolemia receiving maximally tolerated statins. The toxicokinetic, pharmacodynamic, and safety profiles of inclisiran when coadministered with a statin were characterized in cynomolgus monkeys. Six cohorts of monkeys were administered either atorvastatin (40 mg/kg, reduced to 25 mg/kg during the study, daily, oral gavage), inclisiran (300 mg/kg every 28 days, subcutaneous administration), atorvastatin (40/25 mg/kg) and inclisiran combinations (30, 100, or 300 mg/kg), or control vehicles over 85 days followed by 90 days' recovery.

Evaluation of the distribution and excretion of [C]-inclisiran following single subcutaneous administration in cynomolgus monkeys.

Inclisiran is a small interfering RNA molecule that was designed to reduce plasma low-density lipoprotein cholesterol (LDL-C) levels by inhibiting proprotein convertase subtilisin/kexin type 9 synthesis in the liver. This study aimed to characterize the tissue distribution and excretion of inclisiran after dosing in monkeys. A single 20 mg/kg subcutaneous injection of [C]-inclisiran was administered to 12 male cynomolgus monkeys.

In Vitro Drug-Drug Interaction Evaluation of GalNAc Conjugated siRNAs Against CYP450 Enzymes and Transporters.

Small interfering RNAs (siRNAs) represent a new class of medicines that are smaller (∼16,000 Da) than biologic therapeutics (>150,000 Da) but much larger than small molecules (<900 Da). Current regulatory guidance on drug-drug interactions (DDIs) from the European Medicines Agency, Food and Drug Administration, and Pharmaceutical and Medical Devices Agency provides no recommendations for oligonucleotide therapeutics including siRNAs; therefore, small molecule guidance documents have historically been applied. Over ∼10 years, in vitro DDI investigations with siRNAs conjugated to a triantennary -acetylgalactosamine [(GalNAc)-siRNA] ligand have been conducted during nonclinical drug development to elucidate the potential clinical DDI liability.

Toxicologic and Inhibitory Receptor Actions of the Etomidate Analog ABP-700 and Its Metabolite CPM-Acid.

Background: The etomidate analog ABP-700 produces involuntary muscle movements that could be manifestations of seizures. To define the relationship (if any) between involuntary muscle movements and seizures, electroencephalographic studies were performed in Beagle dogs receiving supra-therapeutic (~10× clinical) ABP-700 doses. γ-aminobutyric acid type A (GABAA) and glycine receptor studies were undertaken to test receptor inhibition as the potential mechanism for ABP-700 seizures.