A New Strategy for Discontinuation of Dual Antiplatelet Therapy: Real Safety and Efficacy of 3-Month Dual Antiplatelet Therapy Following Zotarolimus-Eluting Stent Implantation: RESET Trial Myeong-Ki Hong, MD. Ph D, on behalf of RESET investigators Professor, Division of Cardiology, Severance Cardiovascular Hospital Yonsei University College of Medicine, Seoul, Korea RESET ClinicalTrials.gov identifier: NCT01145079

Funding sources Supported by the Cardiovascular Research Center, Seoul, Korea, Medtronic Inc. and grants from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (No. A085012 and A102064), the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (No. A085136).

Background - I Because one of strong predictor for stent thrombosis is early discontinuation of clopidogrel, prolonged dual antiplatelet therapy (DAPT) is highly recommended. However, prolonged use of clopidogrel is associated with many potential risks; bleeding, higher cost, and poor patient compliance or premature discontinuation. Reports from several trials of the Endeavor zotarolimus-eluting stent (E-ZES) have shown beneficial efficacy and safety, despite a relatively short duration of DAPT. Iakovou I, et al. JAMA 2005;293:2126-30. Pfisterer M, et al. J Am Coll Cardiol 2006;48:2584-91. Brar SS, et al. J Am Coll Cardiol 2008;51:2220-7. Bhatt DL, et al. N Engl J Med 2006;354:1706-17. Grines CL, et al. Circulation 2007;115:813-8. Stone GW, et al. Am J Cardiol 2008;102:1017-22. Fajadet J, et al. Circulation 2006;114:798-806. Meredith IT, et al. Am J Cardiol. 2007;100:S56-S61. Leon MB, et al. J Am Coll Cardiol 2010;55:543-54.

Background - II Recent OCT study reported sufficient strut coverage following E-ZES implantation as early as 3 months post-procedure. Kim JS, et al. J Am Coll Cardiol Intv 2009;2:1240-7.

Background - III A recent registry study reported that low-risk patients with E-ZES + 3-month DAPT (n=661) showed a favorable long-term clinical outcomes after cessation of clopidogrel 3 months post intervention. Hahn JY, et al. Circ J 2010;74:2314-21.

Hypothesis & Objective Three-month DAPT after E-ZES implantation (E-ZES+3-month DAPT) may be non-inferior to 12-month DAPT after implantation with other DES (standard therapy). Objectives; To compare the safety and efficacy between patients treated with E-ZES+3-month DAPT and patients treated with the standard therapy, in the RESET (REal Safety and Efficacy of a 3-month dual antiplatelet Therapy following E-ZES implantation) trial.

Study design and patients Prospective, open label, randomized trial Participating centers; conducted at 26 sites in Korea Randomization Using an interactive web-based response system, study participants were randomly assigned in a 1:1 ratio to receive either the E-ZES or another currently available DES. Stratified by participating center and four clinical or lesion characteristics;

Inclusion criteria Exclusion criteria Patients with stable angina, unstable angina, or acute MI Diameter stenosis ≥ 50% and reference vessel diameter of 2.5 to 4.0 mm by visual estimation Elective PCI, eligible for participation Exclusion criteria Prior history of cerebral vascular accidents, peripheral artery diseases, thromboembolic disease or stent thrombosis Left ventricular ejection fraction < 40% Lesions with in-stent restenotic lesion, chronic total occlusion, or significant left main disease requiring intervention Cardiogenic shock Acute ST-elevation MI within 48 hours after onset of symptoms Contraindication to antiplatelet agents Severe hepatic (≥3 times normal values) or renal dysfunction (serum creatinine >2.0 mg/dl)

Primary end-points A composite of 1) death from cardiovascular cause, 2) myocardial infarction, 3) stent thrombosis *, 4) ischemia-driven target-vessel revascularization or 5) bleeding † at 1 year post-procedure. * Stent thrombosis, defined as definite or probable stent thrombosis by ARC definition † Bleeding, defined as TIMI-defined major or minor bleeding Post-procedure clinical follow-up; in-hospital, and after 1, 3, 6 and 12 months either by clinic visit or by telephone interview

Sample size calculation A non-inferiority comparison Overall incidence of the primary endpoint of two groups; E-ZES+3-month DAPT; 10% Standard therapy; 11% We hypothesized that the clinical outcome of E-ZES+3-month DAPT would be non-inferior to the other group with a non-inferiority margin of 4% for the absolute difference in risk at 12 months.  Assuming a 10% drop out rate, this required an estimated sample size of 2,120 patients (1,060 for each group) to achieve 80% power for non-inferiority test and a one-sided type I error of 5%.

Statistical analysis All comparisons, according to the intention-to-treat allocations. Cumulative event rates, estimated by the Kaplan-Meier method (using log-rank test) and calculated the absolute differences and 95% confidence intervals (CI). P-value <0.05 were considered statistically significant. Statistical Analysis System software (SAS; 9.1.3., SAS Institute, NC) and R version 2.12.2 (R Development Core Team, Vienna, Austria).

Study organization Principal investigator; Professor Myeong-Ki Hong, MD, Ph D, Yonsei University College of Medicine, Seoul, Korea Steering committee; Myeong-Ki Hong, MD, Yonsei University College of Medicine, Seoul, Korea Yangsoo Jang, MD, Yonsei University College of Medicine, Seoul, Korea Joo-Young Yang, MD, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea Hyuck-Moon Kwon, MD, Kangnam Severance Hospital, Seoul, Korea Jung-Han Yoon, MD, Yonsei University Wonju College of Medicine, Wonju, Korea Dong-Woon Jeon, MD, National Health Insurance Corporation Ilsan Hospital, Goyang, Korea Seung-Whan Lee, MD, Wonju Christian Hospital, Wonju, Korea Byung-Ok Kim, MD, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea Bum-Kee Hong, MD, Kangnam Severance Hospital, Seoul, Korea Coordinating center; Cardiovascular Research Center, Seoul Korea Data safety monitoring board (DSMB); Chul-Min Ahn, MD, Korea University College of Medicine, Seoul, Korea Hyuck-Jai Chang, MD, Yonsei University College of Medicine, Seoul, Korea Seong-Hoon Choi, MD, Hallym University College of Medicine, Seoul, Korea Deok-Kyu Cho, MD, Kwandong University College of Medicine, Goyang, Korea Clinical event committee (CEC); Eui-Young Choi, MD, Kangnam Severance Hospital, Seoul, Korea Ji-Young Shim, MD, Yonsei University College of Medicine, Seoul, Korea Se-Jung Yoon, MD, NHIC Ilsan Hospital, Koyang, Korea Jang Young Kim, MD, Wonju Christian Hospital, Wonju, Korea Data management and biostatistical analysis; Jung Mo Nam, Ph D, Department of Preventive Medicine and Biostatistics, Yonsei University College of Medicine, Seoul, Korea Dong-Ho Shin, MD, MPH, Yonsei University College of Medicine, Seoul, Korea

Study at a glance & Final Enrollment 2,148 patients enrolled and randomized Divided into 4 subsets and 1:1 randomization was performed. E-ZES + 3-month DAPT Standard Therapy: Other DES with 12-month DAPT 31 patients excluded - 16 Withdrawal of consent - 15 Met exclusion criteria E-ZES + 3-month DAPT (n=1059) Standard therapy (n=1058) Diabetes mellitus subset (N=292) Acute coronary syndrome subset (N=601) Short-length DES Subset (N=681) Long-length DES Subset (N=543) E-ZES (n=146) R-ZES (n=146) E-ZES (n=301) R-ZES (n=300) E-ZES (n=341) SES (n=340) E-ZES (n=271) EES (n=272) R-ZES = Resolute zotarolimus-eluting stent ; SES = sirolimus-eluting stent; EES = everolimus-eluting stents 13

Baseline clinical characteristics Variables E-ZES+3-month DAPT (n=1,059) Standard therapy (n=1,058) P Age (year) 62.4±9.4 62.4±9.8 0.94 Male sex, n (%) 682 (64.4) 665 (62.9) 0.47 Body mass index, kg/m2 25.0±3.2 24.9±3.1 0.50 Hypertension, n (%) 660 (62.3) 650 (61.4) 0.69 Diabetes mellitus, n (%) 316 (29.8) 305 (28.8) 0.63 Dyslipidemia, n (%) 611 (57.7) 634 (59.9) 0.31 Current smoker, n (%) 267 (25.2) 241 (22.8) 0.20 Congestive heart failure, n (%) 120 (11.3) 125 (11.8) 0.74 Ejection fraction, % 64.2±9.4 63.9±9.4 0.45 Prior myocardial infarction, n (%) 19 (1.8) 17 (1.6) 0.87 Prior percutaneous coronary intervention, n (%) 37 (3.5) 32 (3.0) Prior coronary bypass surgery, n (%) 2 (0.2) 6 (0.6) 0.18 Clinical presentation, n (%)   0.66 Stable angina 471 (44.5) 490 (46.3) Unstable angina 432 (40.8) 422 (39.9) Acute myocardial infarction 156 (14.7) 146 (13.8) Medications at discharge Statins, no. (%) 923 (87.2) 914 (86.4) 0.61 Beta blockers, no. (%) 712 (67.2) 730 (69.0) 0.40 ACE inhibitors, no. (%) 331 (31.3) 349 (33.0) Angiotensin receptor blockers, no. (%) 323 (30.5) 301 (28.4) 0.32

Baseline angiographic characteristics Variables E-ZES+3-month DAPT (n=1,059) Standard therapy (n=1,058) P No. of lesions 1341 1346   Treated vessel, LAD, n (%) 707 (52.7) 722 (53.6) 0.54 ACC/AHA class B2/C C, n (%) 910 (67.9) 932 (69.2) 0.46 Lesion length, mm 19.6±10.1 20.1±10.8 0.21 Type of drug-eluting stent, n (%) Endeavor zotarolimus-eluting stents 1341 (100.0) - Cypher sirolimus-eluting stents 383 (28.5) Xience everolimus-eluting stents 404 (30.0) Resolute zotarolimus-eluting stents 559 (41.5) Multi-vessel intervention / patients, n (%) 233 (22.0) 248 (23.4) 0.44 Number of lesions per patient 1.27±0.53 1.27±0.68 0.88 Stent diameter, mm 3.18±0.42 3.17 ± 0.83 0.63 Stent length per lesion, mm 22.7±10.1 22.9±10.7 0.35 Adjuvant post-dilation, n (%) 539 (40.2) 540 (40.1) 0.97 Maximum stent pressure, atm 16.2±3.7 16.5±3.6 Use of GP IIb/IIIa inhibitors/patient, n (%) 20 (1.9) 21 (2.0) 0.89 Procedure success, no. (%) 1339 (99.9) 1345 (99.9)

Quantitative Angiographic analysis Variables E-ZES+3-month DAPT (n=1,059) Standard therapy (n=1,058) P No. of lesions 1341 1346   Pre-intervention Reference vessel diameter, mm 3.0±0.5 0.13 Minimum luminal diameter, mm 1.1±0.5 1.0±0.5 0.23 Percent diameter stenosis, % 65.0±14.1 65.5±13.8 0.36 Post-intervention In-stent 2.7±0.4 0.28 In-segment 2.2±0.5 2.1±0.5 0.58 11.2±7.8 11.1±8.1 0.65 30.7±11.7 0.83

Clinical follow-up at 1 year Clinical follow-up at 1 year was completed for 2,086 of 2,117 patients (98.5%): 1,044 of 1,059 patients (98.6%) in E-ZES+3-month DAPT vs. 1,042 of 1,058 patients (98.5%) in standard therapy group (p=0.99).

Primary endpoint, by Kaplan-Meier method * Primary end-point; A composite of death from CV cause, MI, stent thrombosis, TVR or bleeding at 1 year 8 Standard therapy E-ZES + 3-month DAPT Difference = 0.0% 95% CI, -2.5 to 2.5; p = 0.84 6 4.7% 4.7% p-value for non-inferiority < 0.01 Cumulative event rate (%) 4 2 6 12 Months No. at Risk E-ZES +3-month DAPT 1059 1049 1037 1027 945 Standard therapy 1058 1046 1032 1024 920

Any death, MI, or stent thrombosis 8 Standard therapy E-ZES + 3-month DAPT p-value by log-rank test = 0.48 6 4 Cumulative event rate (%) 2 1.3% 0.8% 6 12 Months No. at Risk E-ZES+ 3-month DAPT 1059 1051 1045 1041 966 Standard therapy 1058 1042 1037 937

Individual component of primary endpoint (ITT) Variables E-ZES+3-month DAPT (n=1,059) Standard therapy (n=1,058) Difference (95% CI) p Death, n (%)   From any cause 5 (0.5) 8 (1.0) -0.5% (-1.4 – 0.4) 0.39 From cardiovascular cause 2 (0.2) 4 (0.4) -0.2% (-0.6 – 0.3) 0.41 MI, n (%) -0.2% (-0.7 ~ 0.3) TVR, n (%) 31 (3.9) 27 (3.7) 0.2% (-2.3 – 2.6) 0.70 Non-TVR, n (%) 15 (1.5) 11 (1.5) 0.0% (-1.3 – 1.4) 0.52 Stent thrombosis, n (%) 3 (0.3) -0.1% (-0.5 – 0.3) 0.65 < 1months 2 1-3 months 3-12 months 3 Bleeding, n (%) Major or minor 10 (1.0) -0.5% (-1.2 – 0.2) 0.20 Major 6 (0.6) -0.4% (-0.9 – 0.1) 0.16 CVA, n (%) 6 (0.7) 0.1% (-0.1 – 1.0) 0.96

Subgroup analysis

Duration of dual antiplatelet therapy Mean duration of DAPT; E-ZES+3-month DAPT group: 93±28 days (median, 93 day) Standard therapy group: 364±31 days (median, 363 day) Interruption of DAPT regimen in E-ZES + 3-month DAPT group occurred in 62 / 1,059 patients (5.9%) (mean duration of DAPT, 196±63 days; median, 173 day for the 62 patients). Reasons for interruption of the DAPT regimen; physicians’ mistake or failure of monitoring (n=26) physicians’ discretion (n=22) patients’ disagreement (n=13) repeat revascularization (n=1)

Clinical outcomes of both groups, *per protocol analysis Characteristics E-ZES+3-month DAPT (n=997) Standard therapy (n=1,058) Difference (95% CI) p Primary endpoint, n (%) 36 (4.6) 41 (4.7) -0.1% (-2.7–2.4) 0.69 Any death, MI, or ST, n (%) 6 (0.6) 11 (1.3) -0.7% (-1.6–0.3) 0.27 CV Death or MI, n (%) 4 (0.4) 7 (0.7) -0.3% (-0.9–0.4) 0.42 Each components   Death, n (%) From any cause 3 (0.3) 8 (1.0) -0.7% (-1.5–0.2) 0.15 From cardiovascular cause 2 (0.2) -0.2% (-0.6–0.3) 0.46 MI, n (%) -0.2% (-0.7–0.3) TVR, n (%) 27 (3.7) 0.0% (-2.5–2.4) 0.94 Non-TVR, n (%) 14 (1.5) 11 (1.5) 0.0% (-1.4–1.4) 0.55 Stent thrombosis, n (%) -0.1% (-0.5–0.3) 0.70 < 1months 2 1-3 months 3-12 months 3 Bleeding, n (%) Major or minor 5 (0.5) 10 (1.0) -0.5% (-1.2–0.3) 0.24 Major -0.4% (-0.9–0.2) 0.18 CVA, n (%) 6 (0.7) -0.2% (-0.9–0.6) 0.80 ; * Analysis after exclusion of the patients with interrupting 3-month DAPT

Summary E-ZES+3-month DAPT was non-inferior to the standard therapy for the primary endpoint (defined as a composite of death from CV cause, MI, stent thrombosis, TVR or bleeding at 1 year). The occurrence of stent thrombosis was similar between the two groups: From 3 months through 12 months following the index procedure, there were no stent thrombosis events in the E-ZES+3-month DAPT group. There were no significant difference of the other composite events or individual component of primary endpoint.

Limitations One year of clinical follow-up may not be sufficient to assess the fatal late outcomes (e.g, very late stent thrombosis). Because the patients with very high risks were not included, the generalized application of these results to the entire population demands careful attention. The comparator group was not treated with a single DES type. There was no 3-month vs. 12-month DAPT either within E-ZES or within other DES. - However, hypothesis of protection by E-ZES was the main objective of this trial and the 1:1 matched randomization between E-ZES and the comparative DES was performed.

Conclusion E-ZES + 3-month DAPT could be safe and beneficial for the selected patients with coronary artery disease who may need to stop DAPT early after DES implantation.

Clinical implications As an alternative PCI strategy, E-ZES + 3-month DAPT could be useful for the selected patients, those at risk for bleeding complications those at risk of poor compliance with medication, especially in the elderly population those with a high probability of unexpected non-cardiac surgery or invasive procedures those with a low risk of stent thrombosis