RNA as Medicine: The Pharmacological Revolution of Therapeutic Oligonucleotides- A Review article

Therapeutic oligonucleotides have matured into clinically validated medicines across neurology, hepatic/metabolic disease, cardiometabolic risk, and infectious disease. Antisense oligonucleotides (ASOs) act via RNase H–mediated degradation or splice modulation, with intrathecal splice-switching improving motor outcomes in spinal muscular atrophy and exhibiting month-scale CNS tissue half-lives. Gapmer ASOs that suppress transthyretin (TTR) synthesis deliver meaningful neuropathy improvements but require platelet and renal monitoring consistent with phosphorothioate backbones. Small interfering RNAs (siRNA) achieve potent, durable hepatic gene silencing through two delivery paradigms: subcutaneous N-acetylgalactosamine (GalNAc) conjugates with short plasma but long hepatic residence enabling quarterly to twice-yearly maintenance, and intravenous lipid nanoparticles (LNPs) that provide efficient hepatic uptake with manageable infusion reactions. Clinically, this translates to large attack reductions in acute hepatic porphyria, sustained ~50% LDL-C lowering with twice-yearly dosing in hypercholesterolemia, and ~90% TTR reduction with functional benefit in amyloidosis. mRNA vaccines using N1-methylpseudouridine and LNPs demonstrated rapid design-to-clinic timelines and high efficacy at population scale, establishing a manufacturable platform now extending toward therapeutic mRNA applications. Safety profiles largely reflect chemistry and delivery and are mitigable by sequence design, dosing strategies, premedication (for IV LNPs) - and routine laboratory monitoring. Extrahepatic targeting, stereo-controlled chemistries that enhance the potency without class toxicity and model based interval selection can expand organ reach and therapeutic breadth.