Tissue pharmacokinetics of antisense oligonucleotides

Area of Science:

• Pharmacology
• Drug Discovery
• Molecular Biology

Background:

• Antisense oligonucleotides (ASOs) are a promising therapeutic modality.
• Understanding tissue pharmacokinetics (PK) and RNA knockdown is crucial for ASO drug development.
• Current knowledge on how ASO chemistry, conjugation, and administration route impact tissue PK and efficacy is limited.

Purpose of the Study:

• To characterize the concentration-time profiles and RNA knockdown of a locked nucleic acid (LNA) gapmer ASO in mouse tissues after subcutaneous and intratracheal administration.
• To evaluate the impact of a liver-targeting galactosamine conjugate on ASO PK and knockdown.
• To compare the tissue PK of different ASO ribose chemistries (LNA, cEt, 2'-MOE) and investigate sequence-dependent PK variations.

Main Methods:

• Quantitative analysis of ASO concentrations in mouse liver, kidney, heart, and lung using LC-MS/MS.
• Measurement of target RNA knockdown via RT-qPCR.
• Administration of ASOs via subcutaneous and intratracheal routes.
• Evaluation of different ASO chemistries and a galactosamine conjugate.

Main Results:

• Tissue exposure and RNA knockdown varied significantly based on administration route and conjugation strategy.
• Tissue PK profiles were similar across LNA, cEt, and 2'-MOE chemistries.
• ASO half-life in mouse liver showed potential sequence dependency.
• Liver concentration increase was less than dose-proportional between 3-30 μmol/kg.

Conclusions:

• Administration route and conjugation critically influence ASO tissue distribution, exposure, and efficacy.
• Different ASO ribose chemistries exhibit comparable tissue PK profiles.
• These findings provide essential data for optimizing ASO design and interpreting in vivo studies, advancing ASO therapeutic development.