Ray, Kausik K.

Abstract Background PCSK9 inhibitors and statins both lower LDL-C by increasing LDL-receptor (LDLR) function. PCSK9 inhibitors lower Lp(a) by 20–30%, whereas statins do not lower Lp(a). The mechanism by which PCSK9 inhibitors lower Lp(a) is unclear. We assessed the role of the LDLR in Lp(a) reductions produced by inclisiran, an siRNA which prevents hepatic synthesis of PCSK9. Methods ORION-1 was a phase 2 trial of inclisiran in subjects at high ASCVD risk with elevated LDL-C on optimized statin therapy. Subjects received one dose of inclisiran (200, 300, or 500 mg) or two doses at days 1 and 90 (100, 200, or 300 mg). We assessed the correlations between % change in Lp(a) and LDL-C at Day 180 for the inclisiran groups using Spearman correlation coefficients. We additionally assessed the correlation between % change in Lp(a) and absolute change in LDL-C as a proxy for LDLR expression. Lp(a) was measured using an isoform-independent assay and LDL-C with β-quantification. Results ORION-1 included 501 subjects; mean age 63; 65% male; 73% on statins. Median baseline Lp(a) was 37.0 nmol/l (IQR: 11.5–142.0 nmol/l), median LDL-C was 117.0 (IQR: 92.5–149.5 mg/dL). Inclisiran dose-dependently lowered Lp(a) by 14% to 26%. Overall, there was a significant but weak correlation between % change in Lp(a) LDL-C (Spearman coefficient 0.35, p<0.001). This correlation appeared to be stronger at higher inclisiran doses and with repeat dosing (table), as well as in statin-users versus non-users (Spearman coefficient 0.37 vs. 0.21). The correlation between % Lp(a) change and absolute LDL-C change was weaker (0.27, p<0.001). Correlation coefficients LDL-C – Lp(a) Single-dose groups Two-dose groups Inclisiran overall 200 mg (n=60) 300 mg (n=60) 500 mg (n=60) 100 mg (n=59) 200 mg (n=60) 300 mg (n=59) Lp(a) ∼ % change LDL-C 0.22 0.26 0.22 0.29 0.47 0.51 0.35 Lp(a) ∼ absolute change LDL-C 0.35 0.12 0.04 0.22 0.45 0.24 0.27 Lp(a) ∼ % change LDL-C - Statin users 0.16 0.28 0.28 0.31 0.45 0.55 0.37 Lp(a) ∼ % change LDL-C - Non statin users 0.80 -0.08 0.09 0.10 0.63 0.09 0.21 Conclusion The dose-dependent correlation between % changes in LDL-C and Lp(a) suggests that the LDLR may be partially responsible for Lp(a) reductions produced by inclisiran. The numerically stronger correlation in statin-users supports the idea that LDL-C may compete with Lp(a) for LDLR binding especially at low LDL-C levels. Acknowledgement/Funding The Medicines Company

OBJECTIVE To evaluate the efficacy and safety of inclisiran by diabetes status. RESEARCH DESIGN AND METHODS ORION-1 (ClinicalTrials.gov, NCT02597127) randomized 501 subjects with atherosclerotic cardiovascular disease (ASCVD) or ASCVD risk equivalents and high LDL cholesterol (LDL-C), despite maximally tolerated LDL-C–lowering therapies, to one or two doses of placebo or inclisiran. Levels of lipids and proprotein convertase subtilisin/kexin type 9 (PCSK9) at baseline and day 180 were compared. RESULTS Inclisiran was associated with marked declines in LDL-C (median −28% to −52%, P &lt; 0.0001 and −28% to −55%, P &lt; 0.005 for all doses in the without- and with-diabetes groups, respectively) and PCSK9. The inclisiran-treated groups also had lower apolipoprotein B, non-HDL cholesterol, and lipoprotein(a) but higher HDL cholesterol. Inclisiran had an adverse profile similar to that of placebo, and adverse events were proportionally balanced in the baseline with- and without-diabetes groups. CONCLUSIONS PCSK9-targeted siRNA-driven strategies may provide a novel therapeutic option for managing dyslipidemia in the presence and absence of diabetes.

Background: The ORION-1 trial (Trial to Evaluate the Effect of ALN-PCSSC Treatment on Low Density Lipoprotein Cholesterol [LDL-C]) demonstrated that inclisiran, an siRNA therapeutic that targets protease proprotein convertase subtilisin/kexin type 9 mRNA within hepatocytes, produces significant low-density lipoprotein cholesterol reduction. The effects of inclisiran on other lipids are less well described. Methods: ORION-1 was a phase 2 trial assessing 6 different inclisiran dosing regimens versus placebo. Participants with elevated low-density lipoprotein cholesterol despite receiving maximally tolerated statin therapy received a single-dose (200, 300, or 500 mg) or 2-dose starting regimen (100, 200, or 300 mg on days 1 and 90) of inclisiran or placebo. This prespecified analysis reports the percentage reductions in non–high-density lipoprotein cholesterol (non–HDL-C), apolipoprotein (apo) B, very-low-density lipoprotein cholesterol, lipoprotein(a), triglycerides, HDL-C, and apo A1 at the primary efficacy time point (day 180) with mixed-effect models for repeated measures. Additional prespecified analyses report time course of changes from baseline at each visit to day 210, interindividual variation in response, and lipid goal attainment. Results: The mean age of the 501 participants was 63 years, 65% were male, 69% had atherosclerotic cardiovascular disease, 73% used statins, and mean low-density lipoprotein cholesterol was 128 mg/dL. A single dose of inclisiran reduced apo B, non–HDL-C, and very-low-density lipoprotein cholesterol over 210 days. A second dose of inclisiran provided additional lowering of these lipids. At day 180, non–HDL-C was lowered dose-dependently: by 25% from 148±43 to 110±45 mg/dL in the 200-mg single-dose group and by 46% from 161±58 to 91±58 mg/dL in the 2-dose 300-mg group. For the same dosing regimens, apo B was reduced by 23% from 101±23 to 78±29 mg/dL and by 41% from 106±31 to 65±33 mg/dL ( P <0.001 for all groups versus placebo). In the 300-mg 2-dose group, all individuals experienced apo B and non–HDL-C reductions. There was larger interindividual variation in very-low-density lipoprotein cholesterol, triglycerides, and lipoprotein(a) reductions. In the 300-mg 2-dose group, the percentages of patients achieving guideline-recommended apo B goals for high- and very-high-risk patients at day 180 were 78% and 90%; 68% and 83% of participants achieved non–HDL-C <100 and <130 mg/dL. Conclusions: Inclisiran produces significant and prolonged reductions in atherogenic lipoproteins, suggesting that inhibiting the synthesis of protease proprotein convertase subtilisin/kexin type 9 through siRNA may be a viable alternative to other approaches that target protease proprotein convertase subtilisin/kexin type 9. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02597127.