A review.The research of Lindholm et al. is mainly described.Lindholm et al. demonstrated that a 1 mo course of weekly s.c. therapy with either of two locked nucleic acid (LNA) antisense oligonucleotides targeting PCSK9 rapidly decreases the expression of both PCSK9 and circulating LDL cholesterol without reported toxicity.Two different antisense oligonucleotides, SPC4061 and SPC5001, are compared to a control, SPC3088.Despite similar in vitro activity of the two antisense oligonucleotides, SPC5001 proved to be significantly more potent than SPC4061 in the multiple dose monkey study, reducing circulating PCSK9 protein by 85% compared to 50% in the monkeys dosed with SPC4061.