Effect of the PCSK9 Inhibitor, Evolocumab, on the Composition of Coronary Atherosclerosis: Insights from the GLAGOV Trial SJ Nicholls, H Kassahun, DM Brennan, K Wolski, J Yang, R Somaratne, SM Wasserman and SE Nissen

Disclosures Research support: AstraZeneca, Amgen, Anthera, Eli Lilly, Esperion, Novartis, Cerenis, The Medicines Company, Resverlogix, InfraReDx, Roche, Sanofi-Regeneron and LipoScience Consulting and honoraria: AstraZeneca, Eli Lilly, Anthera, Omthera, Merck, Takeda, Resverlogix, Sanofi-Regeneron, CSL Behring, Esperion, Boehringer Ingelheim

Amgen Proprietary - Confidential Background The PCSK9 inhibitor, evolocumab, lowers LDL-C, induces plaque regression on IVUS and reduces CV events in statin-treated ASCVD patients The impact of PCSK9 inhibition on the composition of coronary atheroma has not been investigated. Virtual histology is an experimental technique which characterizes plaque composition and may have utility in assessing effects of anti-atherosclerotic therapies.

GLAGOV Trial Schematic Amgen Proprietary - Confidential GLAGOV Trial Schematic 968 patients with angiographic CAD, stable statin dose and LDL-C ≥80 mg/dL OR 60-80 mg/dL and 1 major or 3 minor risk factors Screening, placebo run-in period Coronary Angiogram Baseline IVUS Up to 4 week lipid stabilization period Placebo SC monthly Randomization End of Study IVUS Evolocumab 420 mg SC monthly 2-4 weeks Max. 6 weeks Week 4 12 24 36 52 64 70 76 80

Amgen Proprietary - Confidential GLAGOV VH Substudy Amgen Proprietary - Confidential Determine if evolocumab produced changes in VH- derived plaque components (dense calcium, fibrous, fibrofatty, necrotic core) compared with placebo in 331 patients with evaluable VH imaging. The prespecified statistical plan sought to compare changes in volumetric measures, adjusting for baseline values and multiple comparisons. The primary endpoint was the absolute change in dense calcium volume from baseline to week 78.

Baseline Demographics and Statin Usage Characteristic Placebo (n=167) Evolocumab (n=164) Age 59.7 59.3 Male Gender 76.0% 70.7% BMI (kg/m2) 29.5 29.7 Diabetes 16.2% 18.9% Smoking 22.2% 29.9% Baseline statin use 99.4% 98.8% High intensity 57.5% 59.8% Moderate intensity 41.3% 37.8% Baseline LDL-C (mg/dL) 92.0 90.9 Baseline CRP (mg/L) 1.5 1.7

Percent Change in Biochemical Parameters Amgen Proprietary - Confidential Percent Change in Biochemical Parameters Characteristic Placebo (n=167) Evolocumab (n=164) P Value LDL Cholesterol +0.6% -62.8%*** <0.0001 HDL Cholesterol +7.5%*** +11.6%*** 0.02 Triglycerides +2.7%* -11.5%** 0.0002 CRP -21.4% -6.7%** 0.11 Lp(a) -2.5% -22.7%*** * P<0.05, ** P<0.01 and *** P<0.0001 compared with baseline

Change in Measures of Plaque Burden Amgen Proprietary - Confidential Characteristic Placebo (n=167) Evolocumab (n=164) P Value PAV (%) +0.17 -1.20* <0.0001 TAV (mm3) -0.8 -3.6* 0.04 PAV regressors (%) 46.1 68.3 TAV regressors (%) 53.3 64.6 PAV: percent atheroma volume; TAV: total atheroma volume. * P<0.0001 compared with baseline

Primary Endpoint: Change in Normalized Dense Calcium Volume 0.6* 1.0** P=0.49*** Statin Monotherapy Statin + Evolocumab * P<0.05 and ** P<0.001 compared with baseline (exploratory analysis). *** Hochberg adjusted p value

Secondary Endpoint: Change in Volume of Other VH Parameters -3.0* P=0.49*** -5.0** -2.4** -3.0** -0.6 -0.1 Statin Monotherapy Statin + Evolocumab Fibrofatty Necrotic Core Fibrous * P<0.01 and ** P<0.001 compared with baseline (exploratory analysis). *** Hochberg adjusted p value

Amgen Proprietary - Confidential Secondary Endpoint: Absolute Change in VH-Derived Percentage Plaque Measures Amgen Proprietary - Confidential Characteristic Placebo (n=167) Evolocumab (n=164) P Value** Dense calcium (%) +1.00.4* +2.20.4* 0.10 Fibrofatty (%) -0.91.1 -1.61.1 0.67 Fibrous (%) -0.60.8 -1.40.8 Necrotic core (%) +0.40.5 +0.90.6 * P<0.01 compared with baseline (exploratory analysis) **Hochberg adjusted

Correlation Between Change in VH Measures and Biochemical Parameters Characteristic Change LDL-C Change CRP Dense calcium r = -0.15 r = 0.07 Fibrofatty r = 0.03 r = -0.04 Fibrous r = 0.06 r = -0.01 Necrotic core

Amgen Proprietary - Confidential Exploratory Analysis: Change in VH-Derived Plaque Measures and Regression Amgen Proprietary - Confidential Characteristic Tertiles of Change PAV (%) P Value <-1.57 -1.57 – 0.57 >0.57 Dense calcium (mm3) 0.50.3 0.90.3** 1.00.3** 0.65 Fibrofatty (mm3) -6.31.2** -3.71.2** -2.01.2 0.03 Fibrous (mm3) -6.30.7** -2.30.7** 0.50.8 <0.001 Necrotic core (mm3) -2.60.6** 0.10.6 1.30.6* * P<0.05 and ** P<0.01 compared with baseline

Exploratory Analysis: Baseline LDL-C <70 mg/dL Amgen Proprietary - Confidential Characteristic Placebo (n=26) Evolocumab (n=35) P Value Dense calcium (mm3) +0.40.8 -0.31.7 0.54 Fibrofatty (mm3) -6.03.1 -6.72.6** 0.87 Fibrous (mm3) -0.82.0 -3.41.7* 0.32 Necrotic core (mm3) +0.41.4 -2.91.2* 0.08 * P<0.05 and ** P<0.01 compared with baseline

Amgen Proprietary - Confidential Conclusion Evolocumab on a background of optimal statin therapy produced robust lowering of LDL cholesterol and plaque regression by conventional IVUS. However, VH imaging failed to detect any difference between treatment groups for individual plaque components. These findings further fuel uncertainty regarding the utility of VH imaging in drug development to assess the effect of anti-atherosclerotic therapies.

Amgen Proprietary - Confidential Final Thoughts Amgen Proprietary - Confidential The inverse correlation between changes in LDL cholesterol and plaque calcium supports prior reports in studies of high intensity statins. While the underlying mechanism remains uncertain, it questions the use of serial calcium scoring to monitor responses to lipid lowering interventions. VH yields predictable, but not incremental information, in the setting of plaque regression. It will be of interest to see if other modalities can provide better insights.