Pharmacokinetics of antisense oligonucleotides

Area of Science:

• Pharmacology
• Oligonucleotide Therapeutics

Background:

• Antisense oligonucleotides (ASOs) are emerging as potent therapeutic agents for severe diseases.
• Understanding ASO pharmacokinetics is crucial for their clinical development.

Purpose of the Study:

• To evaluate the in vivo pharmacokinetics and tissue distribution of different oligonucleotide analogues.
• To assess the therapeutic potential of phosphorothioate (S-oligonucleotide) and methylphosphonate oligonucleotides.

Main Methods:

• Intravenous and subcutaneous administration of oligonucleotide analogues in various animal models (monkeys, rats, mice).
• Plasma elimination half-life determination.
• Organ distribution and excretion studies (urine).

Main Results:

• Phosphodiester oligonucleotides showed rapid degradation (5-minute half-life).
• Phosphorothioate oligonucleotides exhibited biphasic elimination with a long terminal half-life (35-50 hours) after IV administration, consistent with subcutaneous delivery.
• Methylphosphonate oligonucleotides had a shorter half-life (17 minutes).
• S-oligonucleotides distributed to major organs, with high concentrations in the liver and kidneys, and were primarily excreted in urine.
• Steady-state plasma concentrations were achieved during repeated S-oligonucleotide administration in rats.

Conclusions:

• Phosphorothioate and methylphosphonate oligonucleotides demonstrate favorable pharmacokinetic profiles for in vivo therapeutic applications.
• The long elimination half-life and wide organ distribution of S-oligonucleotides support their potential as drug candidates.