PCSK9 inhibition and LDL cholesterol lowering: the biology of an attractive therapeutic target and critical review of the latest clinical trials

References

• Di Angelantonio E, Sarwar N, Perry P et al. Major lipids, apolipoproteins, and risk of vascular disease. JAMA 302(18), 1993–2000 (2009).
   Google Scholar
• Kolansky DM, Cuchel M, Clark BJ et al. Longitudinal evaluation and assessment of cardiovascular disease in patients with homozygous familial hypercholesterolemia. Am. J. Cardiol. 102(11), 1438–1443 (2008).
   Google Scholar
• Duewell P, Kono H, Rayner KJ et al. NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals. Nature 464(7293), 1357–1361 (2010).
   Google Scholar
• Baigent C, Keech A, Kearney PM et al. Efficacy and safety of cholesterol‑lowering treatment: prospective meta‑analysis of data from 90,056 participants in 14 randomised trials of statins. Lancet 366(9493), 1267–1278 (2005).
   Google Scholar
• Brautbar A, Ballantyne CM. Pharmacological strategies for lowering LDL cholesterol: statins and beyond. Nat. Rev. Cardiol. 8(5), 253–265 (2011).
   Google Scholar
• Cholesterol Treatment Trialists’ (CTT) Collaborators, Mihaylova B, Emberson J et al. The effects of lowering LDL cholesterol with statin therapy in people at low risk of vascular disease: meta‑analysis of individual data from 27 randomised trials. Lancet 380(9841), 581–590 (2012).
   Google Scholar
• Fruchart JC, Sacks F, Hermans MP et al. The Residual Risk Reduction Initiative: a call to action to reduce residual vascular risk in patients with dyslipidemia. Am. J. Cardiol. 102(Suppl. 10), K1–K34 (2008).
   Google Scholar
• Raal FJ, Santos RD, Blom DJ et al. Mipomersen, an apolipoprotein B synthesis inhibitor, for lowering of LDL cholesterol concentrations in patients with homozygous familial hypercholesterolaemia: a randomised, double‑blind, placebocontrolled trial. Lancet 375(9719), 998–1006 (2010).
   Google Scholar
• Cuchel M, Bloedon LT, Szapary PO et al. Inhibition of microsomal triglyceride transfer protein in familial hypercholesterolemia. N. Engl. J. Med. 356(2), 148–156 (2007).
   Google Scholar
• Visser ME, Wagener G, Baker BF et al. Mipomersen, an apolipoprotein B synthesis inhibitor, lowers low‑density lipoprotein cholesterol in high‑risk statin‑intolerant patients: a randomized, double‑blind, placebo‑controlled trial. Eur. Heart J. 33(9), 1142–1149 (2012).
   Google Scholar
• Abifadel M, Varret M, Rabes JP et al. Mutations in PCSK9 cause autosomal dominant hypercholesterolemia. Nat. Genet. 34(2), 154–156 (2003).
   Google Scholar
• Homer VM, Marais AD, Charlton F et al. Identification and characterization of two non‑secreted PCSK9 mutants associated with familial hypercholesterolemia in cohorts from New Zealand and South Africa. Atherosclerosis 196(2), 659–666 (2008).
   Google Scholar
• Benjannet S, Rhainds D, Hamelin J, Nassoury N, Seidah NG. The proprotein convertase (PC) PCSK9 is inactivated by furin and/or PC5/6A: functional consequences of natural mutations and posttranslational modifications. J. Biol. Chem. 281(41), 30561–30572 (2006).
   Google Scholar
• Abboud S, Karhunen PJ, Lutjohann D et al. Proprotein convertase subtilisin/kexin type 9 (PCSK9) gene is a risk factor of large‑vessel atherosclerosis stroke. PLoS ONE 2(10), e1043 (2007).
   Google Scholar
• Chen SN, Ballantyne CM, Gotto AM Jr, Tan Y, Willerson JT, Marian AJ. A common PCSK9 haplotype, encompassing the E670G coding single nucleotide polymorphism, is a novel genetic marker for plasma low‑density lipoprotein cholesterol levels and severity of coronary atherosclerosis. J. Am. Coll. Cardiol. 45(10), 1611–1619 (2005).
   Google Scholar
• Norata GD, Garlaschelli K, Grigore L et al. Effects of PCSK9 variants on common carotid artery intima media thickness and relation to apoE alleles. Atherosclerosis 208(1), 177–182 (2010).
   Google Scholar
• Zhao Z, Tuakli‑Wosornu Y, Lagace TA et al. Molecular characterization of loss‑of‑function mutations in PCSK9 and identification of a compound heterozygote. Am. J. Hum. Genet. 79(3), 514–523 (2006).
   Google Scholar
• Hooper AJ, Marais AD, Tanyanyiwa DM, Burnett JR. The C679X mutation in PCSK9 is present and lowers blood cholesterol in a Southern African population. Atherosclerosis 193(2), 445–448 (2007).
   Google Scholar
• Kotowski IK, Pertsemlidis A, Luke A et al. A spectrum of PCSK9 alleles contributes to plasma levels of low‑density lipoprotein cholesterol. Am. J. Hum. Genet. 78(3), 410–422 (2006).
   Google Scholar
• Cohen JC, Boerwinkle E, Mosley TH Jr, Hobbs HH. Sequence variations in PCSK9, low LDL, and protection against coronary heart disease. N. Engl. J. Med. 354(12), 1264–1272 (2006). Reports on a substantial reduction of cardiovascular risk associated with lifelong moderate reduction in LDL cholesterol (LDL‑C) due to lower plasma PCSK9 levels.
   Google Scholar
• Huang CC, Fornage M, Lloyd‑Jones DM, Wei GS, Boerwinkle E, Liu K. Longitudinal association of PCSK9 sequence variations with low‑density lipoprotein cholesterol levels: the Coronary Artery Risk Development in Young Adults Study. Circ. Cardiovasc. Genet. 2(4), 354–361 (2009).
   Google Scholar
• Benn M, Nordestgaard BG, Grande P, Schnohr P, Tybjaerg‑Hansen A. PCSK9 R46L, low‑density lipoprotein cholesterol levels, and risk of ischemic heart disease: 3 independent studies and meta‑analyses. J. Am. Coll. Cardiol. 55(25), 2833–2842 (2010).
   Google Scholar
• Hallman DM, Srinivasan SR, Chen W, Boerwinkle E, Berenson GS. Relation of PCSK9 mutations to serum low‑density lipoprotein cholesterol in childhood and adulthood (from The Bogalusa Heart Study). Am. J. Cardiol. 100(1), 69–72 (2007).
   Google Scholar
• Brown MS, Goldstein JL. Biomedicine. Lowering LDL – not only how low, but how long? Science 311(5768), 1721–1723 (2006).
   Google Scholar
• Lagace TA, Curtis DE, Garuti R et al. Secreted PCSK9 decreases the number of LDL receptors in hepatocytes and in livers of parabiotic mice. J. Clin. Invest. 116(11), 2995–3005 (2006). Demonstrates that circulating PCSK9 from transgenic mice reduces liver LDL receptor levels during parabiosis experiments with wild‑type mice, suggesting that circulating PCSK9 can be targeted to reduce circulating LDL‑C.
   Google Scholar
• Lakoski SG, Lagace TA, Cohen JC, Horton JD, Hobbs HH. Genetic and metabolic determinants of plasma PCSK9 levels. J. Clin. Endocrinol. Metab. 94(7), 2537–2543 (2009).
   Google Scholar
• Chernogubova E, Strawbridge R, Mahdessian H et al. Common and lowfrequency genetic variants in the PCSK9 locus influence circulating PCSK9 levels. Arterioscler. Thromb. Vasc. Biol. 32(6), 1526–1534 (2012).
   Google Scholar
• Seidah NG, Benjannet S, Wickham L et al. The secretory proprotein convertase neural apoptosis‑regulated convertase 1 (NARC‑1): liver regeneration and neuronal differentiation. Proc. Natl Acad. Sci. USA 100(3), 928–933 (2003).
   Google Scholar
• Hampton EN, Knuth MW, Li J, Harris JL, Lesley SA, Spraggon G. The self‑inhibited structure of full‑length PCSK9 at 1.9 A reveals structural homology with resistin within the C‑terminal domain. Proc. Natl Acad. Sci. USA 104(37), 14604–14609 (2007).
   Google Scholar
• Dewpura T, Mayne J. Analyses of PCSK9 post‑translational modifications using time‑of‑flight mass spectrometry. Methods Mol. Biol. 768, 167–187 (2011).
   Google Scholar
• Mayne J, Dewpura T, Raymond A et al. Novel loss‑of‑function PCSK9 variant is associated with low plasma LDL cholesterol in a French–Canadian family and with impaired processing and secretion in cell culture. Clin. Chem. 57(10), 1415–1423 (2011).
   Google Scholar
• Piper DE, Jackson S, Liu Q et al. The crystal structure of PCSK9: a regulator of plasma LDL cholesterol. Structure 15(5), 545–552 (2007).
   Google Scholar
• Li J, Tumanut C, Gavigan JA et al. Secreted PCSK9 promotes LDL receptor degradation independently of proteolytic activity. Biochem. J. 406(2), 203–207 (2007).
   Google Scholar
• McNutt MC, Lagace TA, Horton JD. Catalytic activity is not required for secreted PCSK9 to reduce low density lipoprotein receptors in HepG2 cells. J. Biol Chem. 282(29), 20799–20803 (2007).
   Google Scholar
• Grefhorst A, McNutt MC, Lagace TA, Horton JD. Plasma PCSK9 preferentially reduces liver LDL receptors in mice. J. Lipid Res. 49(6), 1303–1311 (2008).
   Google Scholar
• Awan Z, Seidah NG, MacFadyen JG et al. Rosuvastatin, proprotein convertase subtilisin/kexin type 9 concentrations, and LDL cholesterol response: the JUPITER trial. Clin. Chem. 58(1), 183–189 (2012).
   Google Scholar
• Humphries SE, Neely RD, Whittall RA et al. Healthy individuals carrying the PCSK9 p.R46L variant and familial hypercholesterolemia patients carrying PCSK9 p.D374Y exhibit lower plasma concentrations of PCSK9. Clin. Chem. 55(12), 2153–2161 (2009).
   Google Scholar
• Dubuc G, Tremblay M, Pare G et al. A new method for measurement of total plasma PCSK9: clinical applications. J. Lipid Res. 51(1), 140–149 (2010).
   Google Scholar
• Maxwell KN, Fisher EA, Breslow JL. Overexpression of PCSK9 accelerates the degradation of the LDLR in a postendoplasmic reticulum compartment. Proc. Natl Acad. Sci. USA 102(6), 2069–2074 (2005).
   Google Scholar
• Nassoury N, Blasiole DA, Tebon Oler A et al. The cellular trafficking of the secretory proprotein convertase PCSK9 and its dependence on the LDLR. Traffic 8(6), 718–732 (2007).
   Google Scholar
• Qian YW, Schmidt RJ, Zhang Y et al. Secreted PCSK9 downregulates low density lipoprotein receptor through receptormediated endocytosis. J. Lipid Res. 48(7), 1488–1498 (2007).
   Google Scholar
• Cameron J, Holla OL, Ranheim T, Kulseth MA, Berge KE, Leren TP. Effect of mutations in the PCSK9 gene on the cell surface LDL receptors. Hum. Mol. Genet. 15(9), 1551–1558 (2006).
   Google Scholar
• Blacklow SC. Versatility in ligand recognition by LDL receptor family proteins: advances and frontiers. Curr. Opin Struct. Biol. 17(4), 419–426 (2007).
   Google Scholar
• Jeon H, Blacklow SC. Structure and physiologic function of the low‑density lipoprotein receptor. Annu. Rev. Biochem. 74, 535–562 (2005).
   Google Scholar
• Zhang DW, Lagace TA, Garuti R et al. Binding of proprotein convertase subtilisin/ kexin type 9 to epidermal growth factor‑like repeat A of low density lipoprotein receptor decreases receptor recycling and increases degradation. J. Biol Chem. 282(25), 18602–18612 (2007).
   Google Scholar
• Zhang DW, Garuti R, Tang WJ, Cohen JC, Hobbs HH. Structural requirements for PCSK9‑mediated degradation of the lowdensity lipoprotein receptor. Proc. Natl Acad. Sci. USA 105(35), 13045–13050 (2008).
   Google Scholar
• Kwon HJ, Lagace TA, McNutt MC, Horton JD, Deisenhofer J. Molecular basis for LDL receptor recognition by PCSK9. Proc. Natl Acad. Sci. USA 105(6), 1820–1825 (2008). Provides the molecular basis for the interaction of PCSK9 catalytic domain with the EGF‑A repeat of the LDL receptor based on the crystal structure of the complex.
   Google Scholar
• Fisher TS, Lo Surdo P, Pandit S et al. Effects of pH and low density lipoprotein (LDL) on PCSK9‑dependent LDL receptor regulation. J. Biol Chem. 282(28), 20502–20512 (2007).
   Google Scholar
• Bottomley MJ, Cirillo A, Orsatti L et al. Structural and biochemical characterization of the wild type PCSK9–EGF(AB) complex and natural familial hypercholesterolemia mutants. J. Biol Chem. 284(2), 1313–1323 (2009).
   Google Scholar
• McNutt MC, Kwon HJ, Chen C, Chen JR, Horton JD, Lagace TA. Antagonism of secreted PCSK9 increases low density lipoprotein receptor expression in HepG2 cells. J. Biol Chem. 284(16), 10561–10570 (2009).
   Google Scholar
• Surdo PL, Bottomley MJ, Calzetta A et al. Mechanistic implications for LDL receptor degradation from the PCSK9/LDLR structure at neutral pH. EMBO Rep. 12(12), 1300–1305 (2011).
   Google Scholar
• Mayer G, Poirier S, Seidah NG. Annexin A2 is a C‑terminal PCSK9‑binding protein that regulates endogenous low density lipoprotein receptor levels. J. Biol Chem. 283(46), 31791–31801 (2008).
   Google Scholar
• Ni YG, Condra JH, Orsatti L et al. A proprotein convertase subtilisin‑like/kexin type 9 (PCSK9) C‑terminal domain antibody antigen‑binding fragment inhibits PCSK9 internalization and restores low density lipoprotein uptake. J. Biol Chem. 285(17), 12882–12891 (2010).
   Google Scholar
• Tveten K, Holla OL, Cameron J et al. Interaction between the ligand‑binding domain of the LDL receptor and the C‑terminal domain of PCSK9 is required for PCSK9 to remain bound to the LDL receptor during endosomal acidification. Hum. Mol. Genet. 21(6), 1402–1409 (2012).
   Google Scholar
• Yamamoto T, Lu C, Ryan RO. A two‑step binding model of PCSK9 interaction with the low density lipoprotein receptor. J. Biol Chem. 286(7), 5464–5470 (2011).
   Google Scholar
• Holla OL, Cameron J, Tveten K et al. Role of the C‑terminal domain of PCSK9 in degradation of the LDL receptors. J. Lipid Res. 52(10), 1787–1794 (2011).
   Google Scholar
• Poirier S, Mayer G, Poupon V et al. Dissection of the endogenous cellular pathways of PCSK9‑induced low density lipoprotein receptor degradation: evidence for an intracellular route. J. Biol Chem. 284(42), 28856–28864 (2009).
   Google Scholar
• Zaid A, Roubtsova A, Essalmani R et al. Proprotein convertase subtilisin/kexin type 9 (PCSK9): hepatocyte‑specific low‑density lipoprotein receptor degradation and critical role in mouse liver regeneration. Hepatology 48(2), 646–654 (2008).
   Google Scholar
• Cunningham D, Danley DE, Geoghegan KF et al. Structural and biophysical studies of PCSK9 and its mutants linked to familial hypercholesterolemia. Nat. Struct. Mol. Biol. 14(5), 413–419 (2007).
   Google Scholar
• Essalmani R, Susan‑Resiga D, Chamberland A et al. In vivo evidence that furin from hepatocytes inactivates PCSK9. J. Biol Chem. 286(6), 4257–4263 (2011).
   Google Scholar
• Rashid S, Curtis DE, Garuti R et al. Decreased plasma cholesterol and hypersensitivity to statins in mice lacking Pcsk9. Proc. Natl Acad. Sci. USA 102(15), 5374–5379 (2005).
   Google Scholar
• Luo Y, Warren L, Xia D et al. Function and distribution of circulating human PCSK9 expressed extrahepatically in transgenic mice. J. Lipid Res. 50(8), 1581–1588 (2009).
   Google Scholar
• Shan L, Pang L, Zhang R, Murgolo NJ, Lan H, Hedrick JA. PCSK9 binds to multiple receptors and can be functionally inhibited by an EGF‑A peptide. Biochem. Biophys. Res. Commun. 375(1), 69–73 (2008).
   Google Scholar
• Horton JD, Cohen JC, Hobbs HH. PCSK9: a convertase that coordinates LDL catabolism. J. Lipid Res. 50(Suppl.), S172–S177 (2009).
   Google Scholar
• Zhang Y, Zhou L, Kong‑Beltran M et al. Calcium‑independent inhibition of PCSK9 by affinity‑improved variants of the LDL receptor EGF(A) domain. J. Mol. Biol. 422(5), 685–696 (2012).
   Google Scholar
• Brekke OH, Sandlie I. Therapeutic antibodies for human diseases at the dawn of the twentyfirst century. Nat. Rev. Drug Discov. 2(1), 52–62 (2003).
   Google Scholar
• Duff CJ, Scott MJ, Kirby IT, Hutchinson SE, Martin SL, Hooper NM. Antibody‑mediated disruption of the interaction between PCSK9 and the low‑density lipoprotein receptor. Biochem. J. 419(3), 577–584 (2009).
   Google Scholar
• Lipovsek D. Adnectins: engineered targetbinding protein therapeutics. Protein Eng. Des. Sel. 24(1–2), 3–9 (2011).
   Google Scholar
• Chan JC, Piper DE, Cao Q et al. A proprotein convertase subtilisin/kexin type 9 neutralizing antibody reduces serum cholesterol in mice and nonhuman primates. Proc. Natl Acad. Sci. USA 106(24), 9820–9825 (2009). Seminal study that shows that a monoclonal antibody against PCSK9 can increase LDL receptors in wild‑type mice and leads to a marked and sustained reduction of LDL‑C in nonhuman primates.
   Google Scholar
• Ni YG, Di Marco S, Condra JH et al. A PCSK9‑binding antibody that structurally mimics the EGF(A) domain of LDL‑receptor reduces LDL cholesterol in vivo. J. Lipid Res. 52(1), 78–86 (2011).
   Google Scholar
• Zhang L, McCabe T, Condra JH et al. An anti‑PCSK9 antibody reduces LDL cholesterol on top of a statin and suppresses hepatocyte SREBP‑regulated genes. Int. J. Biol Sci. 8(3), 310–327 (2012).
   Google Scholar
• Liang H, Chaparro‑Riggers J, Strop P et al. Proprotein convertase substilisin/kexin type 9 antagonism reduces low‑density lipoprotein cholesterol in statin‑treated hypercholesterolemic nonhuman primates. J. Pharmacol. Exp. Ther. 340(2), 228–236 (2012).
   Google Scholar
• Chaparro‑Riggers J, Liang H, Devay RM et al. Increasing serum half‑life and extending cholesterol lowering in vivo by engineering an antibody with pH‑sensitive binding to PCSK9. J. Biol Chem. 287(14), 11090–11097 (2012).
   Google Scholar
• Graham MJ, Lemonidis KM, Whipple CP et al. Antisense inhibition of proprotein convertase subtilisin/kexin type 9 reduces serum LDL in hyperlipidemic mice. J. Lipid Res. 48(4), 763–767 (2007).
   Google Scholar
• Frank‑Kamenetsky M, Grefhorst A, Anderson NN et al. Therapeutic RNAi targeting PCSK9 acutely lowers plasma cholesterol in rodents and LDL cholesterol in nonhuman primates. Proc. Natl Acad. Sci. USA 105(33), 11915–11920 (2008). Demonstrates the applicability of lipidencapsulated siRNA to in vivo silencing of PCSK9 mRNA in mice and nonhuman primates.
   Google Scholar
• Gupta N, Fisker N, Asselin MC et al. A locked nucleic acid antisense oligonucleotide (LNA) silences PCSK9 and enhances LDLR expression in vitro and in vivo. PLoS ONE 5(5), e10682 (2010).
   Google Scholar
• Lindholm MW, Elmen J, Fisker N et al. PCSK9 LNA antisense oligonucleotides induce sustained reduction of LDL cholesterol in nonhuman primates. Mol. Ther. 20(2), 376–381 (2012).
   Google Scholar
• Fattori E, Cappelletti M, Lo Surdo P et al. Immunization against proprotein convertase subtilisin‑like/kexin type 9 (PCSK9) lowers plasma LDL cholesterol levels in mice. J. Lipid Res. 53(8), 1654–1661 (2012).
   Google Scholar
• Akinc A, Zumbuehl A, Goldberg M et al. A combinatorial library of lipid‑like materials for delivery of RNAi therapeutics. Nat. Biotechnol. 26(5), 561–569 (2008).
   Google Scholar
• Semple SC, Akinc A, Chen J et al. Rational design of cationic lipids for siRNA delivery. Nat. Biotechnol. 28(2), 172–176 (2010).
   Google Scholar
• Cameron J, Bogsrud MP, Tveten K et al. Serum levels of proprotein convertase subtilisin/kexin type 9 in subjects with familial hypercholesterolemia indicate that proprotein convertase subtilisin/kexin type 9 is cleared from plasma by low‑density lipoprotein receptor‑independent pathways. Transl Res. 160(2), 125–130 (2012).
   Google Scholar
• Seidah NG, Prat A. The biology and therapeutic targeting of the proprotein convertases. Nat. Rev. Drug Discov. 11(5), 367–383 (2012).
   Google Scholar
• Crunkhorn S. Trial watch: PCSK9 antibody reduces LDL cholesterol. Nat. Rev. Drug Discov. 11(1), 11 (2012).
   Google Scholar
• Fitzgerald K, Frank‑Kamenetsky M, Mant T et al. Phase I safety, pharmacokinetic, and pharmacodynamic results for ALN‑PCS, a novel RNAi therapeutic for the treatment of hypercholesterolemia. Arterioscler. Thromb. 32, A67 (2012).
   Google Scholar
• Stein EA, Mellis S, Yancopoulos GD et al. Effect of a monoclonal antibody to PCSK9 on LDL cholesterol. N. Engl. J. Med. 366(12), 1108–1118 (2012).
   Google Scholar
• Dias CS, Shaywitz AJ, Wasserman SM et al. Effects of AMG‑145 on low‑density lipoprotein cholesterol levels: results from 2 randomized, double‑blind, placebocontrolled, ascending‑dose Phase 1 studies in healthy volunteers and hypercholesterolemic subjects on statins. J. Am. Coll. Cardiol. 60, 1888–1898 (2012).
   Google Scholar
• Sullivan D, Olsson AG, Scott R et al. Effect of a monoclonal antibody to PCSK9 on lowdensity lipoprotein cholesterol levels in statinintolerant patients: the GAUSS randomized trial. JAMA 1–10 (2012).
   Google Scholar
• Raal F, Scott R, Somaratne R et al. Lowdensity lipoprotein cholesterol‑lowering effects of AMG‑145, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 serine protease in patients with heterozygous familial hypercholesterolemia: the reduction of LDL‑c with PCSK9 inhibition in heterozygous familial hypercholesterolemia disorder (RUTHERFORD) randomized trial. Circulation (2012).
   Google Scholar
• Giugliano RP, Desai NR, Kohli P et al. Efficacy, safety, and tolerability of a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 in combination with a statin in patients with hypercholesterolaemia (LAPLACE‑TIMI 57): a randomised, placebo‑controlled, dose‑ranging, Phase 2 study. Lancet doi: 10.1016/S0140‑6736(12)61770‑ (2012) (Epub ahead of print).
   Google Scholar
• Kohli P, Desai NR, Giugliano RP et al. Design and rationale of the LAPLACE‑TIMI 57 trial: a Phase II, double‑blind, placebo‑controlled study of the efficacy and tolerability of a monoclonal antibody inhibitor of PCSK9 in subjects with hypercholesterolemia on background statin therapy. Clin. Cardiol. 35(7), 385–391 (2012).
   Google Scholar
• Koren MJ, Scott R, Kim JB et al. Efficacy, safety, and tolerability of a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 as monotherapy in patients with hypercholesterolaemia (MENDEL): a randomised, double‑blind, placebo‑controlled, Phase 2 study. Lancet doi: 10.1016/S0140‑6736(12)61771‑1 (2012) (Epub ahead of print).
   Google Scholar
• Stein EA, Gipe D, Bergeron J et al. Effect of a monoclonal antibody to PCSK9, REGN727/ SAR236553, to reduce low‑density lipoprotein cholesterol in patients with heterozygous familial hypercholesterolaemia on stable statin dose with or without ezetimibe therapy: a Phase 2 randomised controlled trial. Lancet 380(9836), 29–36 (2012).
   Google Scholar
• McKenney JM, Koren MJ, Kereiakes DJ, Hanotin C, Ferrand AC, Stein EA. Safety and efficacy of a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 serine protease, SAR236553/REGN727, in patients with primary hypercholesterolemia receiving ongoing stable atorvastatin therapy. J. Am. Coll. Cardiol. 59(25), 2344–2353 (2012).
   Google Scholar
• Geiss HC, Bremer S, Barrett PH, Otto C, Parhofer KG. In vivo metabolism of LDL subfractions in patients with heterozygous FH on statin therapy: rebound analysis of LDL subfractions after LDL apheresis. J. Lipid Res. 45(8), 1459–1467 (2004).
   Google Scholar
• Roth EM, McKenney JM, Hanotin C, Asset G, Stein EA. Atorvastatin with or without an antibody to PCSK9 in primary hypercholesterolemia. N. Engl. J. Med. doi: 10.1056/NEJMoa1201832 (2012) (Epub ahead of print).
   Google Scholar
• Maxwell KN, Soccio RE, Duncan EM, Sehayek E, Breslow JL. Novel putative SREBP and LXR target genes identified by microarray analysis in liver of cholesterol‑fed mice. J. Lipid Res. 44(11), 2109–2119 (2003).
   Google Scholar
• Dubuc G, Chamberland A, Wassef H et al. Statins upregulate PCSK9, the gene encoding the proprotein convertase neural apoptosisregulated convertase‑1 implicated in familial hypercholesterolemia. Arterioscler. Thromb. Vasc. Biol. 24(8), 1454–1459 (2004).
   Google Scholar
• Welder G, Zineh I, Pacanowski MA, Troutt JS, Cao G, Konrad RJ. High‑dose atorvastatin causes a rapid sustained increase in human serum PCSK9 and disrupts its correlation with LDL cholesterol. J. Lipid Res. 51(9), 2714–2721 (2010).
   Google Scholar
• Huijgen R, Boekholdt SM, Arsenault BJ et al. Plasma PCSK9 levels and clinical outcomes in the TNT (Treating to New Targets) trial: a nested case‑control study. J. Am. Coll. Cardiol. 59(20), 1778–1784 (2012).
   Google Scholar
• Davignon J, Dubuc G. Statins and ezetimibe modulate plasma proprotein convertase subtilisin kexin‑9 (PCSK9) levels. Trans. Am. Clin. Climatol. Assoc. 120, 163–173 (2009).
   Google Scholar
• Cameron J, Ranheim T, Kulseth MA, Leren TP, Berge KE. Berberine decreases PCSK9 expression in HepG2 cells. Atherosclerosis 201(2), 266–273 (2008).
   Google Scholar
• Li H, Dong B, Park SW, Lee HS, Chen W, Liu J. Hepatocyte nuclear factor 1alpha plays a critical role in PCSK9 gene transcription and regulation by the natural hypocholesterolemic compound berberine. J. Biol Chem. 284(42), 28885–28895 (2009).
   Google Scholar
• Costet P, Hoffmann MM, Cariou B, Guyomarc’h Delasalle B, Konrad T, Winkler K. Plasma PCSK9 is increased by fenofibrate and atorvastatin in a non‑additive fashion in diabetic patients. Atherosclerosis 212(1), 246–251 (2010).
   Google Scholar
• Troutt JS, Alborn WE, Cao G, Konrad RJ. Fenofibrate treatment increases human serum proprotein convertase subtilisin kexin type 9 levels. J. Lipid Res. 51(2), 345–351 (2010).
   Google Scholar
• Mayne J, Dewpura T, Raymond A et al. Plasma PCSK9 levels are significantly modified by statins and fibrates in humans. Lipids Health Dis. 7, 22 (2008). This important Phase II study has shown the beneficial effect of REGN727, an anti‑PCSK9 antibody on LDL‑C levels in a cohort of 77 subjects with heterozygous mutations in the LDL receptor treated with high doses of statins. Importantly, while a once every 2 week injection resulted in continuous LDL‑C lowering, a rebound in LDL‑C occrurred with a once every 4 week regimen. In patients with primary hypercholesterolemia receiving atorvastatin (10–40 mg daily), REGN727 could further reduce LDL‑C in a dose‑ and frequency‑dependent manner, by up to 72%.
   Google Scholar
• Lambert G, Ancellin N, Charlton F et al. Plasma PCSK9 concentrations correlate with LDL and total cholesterol in diabetic patients and are decreased by fenofibrate treatment. Clin. Chem. 54(6), 1038–1045 (2008).
   Google Scholar
• Kourimate S, Le May C, Langhi C et al. Dual mechanisms for the fibrate‑mediated repression of proprotein convertase subtilisin/ kexin type 9. J. Biol Chem. 283(15), 9666–9673 (2008).
   Google Scholar
• Donnelly LA, Doney AS, Tavendale R et al. Common nonsynonymous substitutions in SLCO1B1 predispose to statin intolerance in routinely treated individuals with Type 2 diabetes: a go‑DARTS study. Clin. Pharmacol. Ther. 89(2), 210–216 (2011).
   Google Scholar
• Brown DJ. New guidelines for low‑density lipoprotein levels from the National Cholesterol Education Program (NCEP): a 2004 update. Prog. Cardiovasc. Nurs. 19(4), 165 (2004).
   Google Scholar
• Virani SS, Woodard LD, Landrum CR et al. Institutional, provider, and patient correlates of low‑density lipoprotein and non‑high‑density lipoprotein cholesterol goal attainment according to the Adult Treatment Panel III guidelines. Am. Heart J. 161(6), 1140–1146 (2011).
   Google Scholar
• Martin SS, Blumenthal RS, Miller M. LDL cholesterol: the lower the better. Med. Clin. North Am. 96(1), 13–26 (2012).
   Google Scholar
• Izrael‑Tomasevic A, Lipari M, Li W et al. Epitope mapping of an anti‑PCSK9 monoclonal antobody by two techniques explains differential recognition of intact and cleaved PCSK9. J. Am. Soc. Mass Spectr. 23(S1), 97 (2012).
   Google Scholar