Dominick J. Angiolillo, MD, PhD, FACC, FESC Director of Cardiovascular Research Assistant Professor of Medicine Antiplatelet Resistance: What Does it Mean and What Should/Can we do About it? CRT 2008 Wednesday February 13 th, 2008

Presenter Disclosure Information Name: Dominick J Angiolillo Within the past 12 months, the presenter or their spouse/partner have had a financial interest/arrangement or affiliation with the organization listed below. Company Name:Relationship: Bristol Myers SquibbConsultant/Speaker bureau Sanofi-AventisConsultant/Speaker bureau Eli LillyConsultant/Speaker bureau Daiichi SankyoConsultant/Speaker bureau PortolaConsultant GSKEducational Grant

Antiplatelet Resistance  - What does it mean?  - What should/can we do?

 - What does it mean?  - What should/can we do? Antiplatelet Resistance

Long-term Efficacy of ASA in Reducing Death or MI in Patients with Unstable Angina Wallentin LC et al JACC 1991;18:1587– Months Probability of death or MI Placebo ASA 75 mg Risk ratio after 1 year % Cl 0.37–0.72 (p=0.0001) ?

Definition(s) of “APT Resistance?” The fact that some patients may experience recurrent vascular events despite the use of APT should be properly defined as “treatment failure” rather than “APT resistance” (multiple pathways mediate thrombotic events). APT Resistance/Non-responsiveness = Failure to inhibit the target APT Resistance/Non-responsiveness ≠ Clinical failure

Gurbel, P. A. et al. Circulation 2007;115: ASPECT study: Individual platelet aggregation data measured after stimuli by 3 concentrations of AA by LTA at 3 different doses of aspirin

Gurbel, P. A. et al. Circulation 2007;115: ASPECT study: Effects of Assay and Dose on Measurement of Aspirin Resistance

ASA-R: mean aggregation ≥70% with 10 µM ADP & ≥20% with 0.5 mg/ml AA Clinical Outcomes: Aspirin Responsiveness Days after Treatment Not Aspirin Resistant, N = 309 Aspirin Resistant, N = 17 % Death, MI, CVA Log rank  2 =5.05, p=0.03 Gum, P. JACC 2003;41:961-5

P2X 1 P2Y 12 ATP Shape change Angiolillo DJ et al JACC 2007 P2Y 1 GqGq Initiation of Platelet Aggregation IP3 PKC GP IIb/IIIa receptor activation G 12 DAG + Shape change Granule secretion Stabilization of Platelet Aggregation βγβγ GP IIb/IIIa receptor activation Rap1b PKB/Akt αiαi AC cAMP VASP VASP-P cAMP GiGi PI3K Clopidogrel 15% active metabolite HOOC * HS N O Cl OCH 3 N S O Cl O CH 3 C 85% inactive metabolites (Esterases in blood) Gastro-intestinal absorption ADP Ca 2+ flux Ca 2+ mobilization PLCβ MLCK-P “Rho” Hepatic CYP Biotransformation AC GsGs GP IIb/IIIa receptor activation PGE 1 PIP2

Adapted from Angiolillo DJ et al. Am J Cardiol. 2006;97: Individual Response Variability to Dual Antiplatelet Therapy in the Steady State Phase of Treatment % Platelet Aggregation (LTA-ADP 20  mol/L) Number of Patients Bleeding risk Ischemic risk

NFunctional ParameterClinical Relevance Matezky et al. Circulation ↑ platelet aggregation (4 th quartile) Post-primary PCI ischemic events (6 months) Gurbel et al. JACC ↑ periprocedrual platelet aggregation Post-PCI ischemic events (6 months) Gurbel et al. Circulation ↑ periprocedrual platelet aggregation Myonecrosis and inflammation marker release Cuisset et al. J Thromb Haemost ↑ platelet aggregation Post-PCI ischemic events (30 days) Lev et al. JACC ↑ clopidogrel/aspirin-resistant patients Post PCI-myonecrosis Cuisset et al. JACC ↑ platelet aggregation Post-PCI ischemic events (30 days) Hocholzer et al. JACC 2006 Geisler et al. Eur Heart J 2006 Bliden et al. JACC 2007 Angiolillo et al. JACC ↑ platelet aggregation (3 rd & 4 th quartiles) ↓ platelet inhibition ↑ platelet aggregation ↑ platelet aggregation (4 th quartile) Post-PCI ischemic events (30 days) Post-PCI ischemic events (3 months) Post-PCI ischemic events (12 months) Ischemic events (24 months) adapted from Angiolillo DJ et al. Am J Cardiov Drugs Post-Stent Ischemic Events and Periprocedural Infarction Clinical Relevance of Clopidogrel Non-responsiveness

NFunctional ParameterClinical Relevance Mueller et al. Thromb Haemost ↓ inhibition of platelet aggregation Stent thrombosis Barragan et al. CCI ↑ P2Y 12 reactivity ratio (VASP-levels) Stent thrombosis Gurbel et al. JACC ↑ P2Y 12 reactivity ratio; ↑platelet aggregation; ↑ stimulated GPIIb/IIIa expression Stent thrombosis Ajzenberg et al. JACC 2005 Buonamici et al JACC ↑ shear-induced platelet aggregation ↑ platelet aggregation Stent thrombosis adapted from Angiolillo DJ et al. Am J Cardiov Drugs Stent Thrombosis Clinical Relevance of Clopidogrel Non-responsiveness

Platelet Reactivity in Patients and Recurrent Events Post-Stenting: Results of the PREPARE POST-STENTING Study Gurbel PA et al. J Am Coll Cardiol. 2005; 46: LTA (20  M ADP) Therapeutic target for P2Y 12 inhibition (?) 50%

High platelet reactivity and MACE in T2DM % Log Rank, p = <62% non-HPR (n=128) >62% HPR (n=45) Months % Event-Free Survival HR: 3.35; 95% CI, ; p= % 86.8% MACE (CV death, STEMI, UA/NSTEMI, stroke) Angiolillo DJ et al. J Am Coll Cardiol 2007; 50: ROC defined cut-off value

Antiplatelet Resistance  - What does it mean?  - What should/can we do?

Aspirin Resistant Patient Management  - Educate patient on importance of compliance

Tantry U et al. JACC 2005 Overestimation of Aspirin Resistance: Key Role of Compliance

Aspirin Resistant Patient Management  - Educate patient on importance of compliance  - Eliminate interfering substances (ibuprofen)  - Increase aspirin dose (?) (.....increasing the dose of aspirin does not enhance COX-1 inhibition)  - Switch to other anti-platelet medications (?) (.....no evidence that switching to alternative treatment strategies improves outcomes)

Cellular Factors Accelerated platelet turnover Reduced CYP3A metabolic activity Reduced CYP3A metabolic activity Increased ADP exposure Increased ADP exposure Up-regulation of the P2Y 12 pathway Up-regulation of the P2Y 12 pathway Up-regulation of the P2Y 1 pathway Up-regulation of the P2Y 1 pathway Up-regulation of P2Y–independent pathways Up-regulation of P2Y–independent pathways (collagen, epinephrine, TXA 2, thrombin) (collagen, epinephrine, TXA 2, thrombin) Clinical Factors Failure to prescribe/poor compliance Under-dosing Under-dosing Poor absorption Poor absorption Drug-drug interactions involving CYP3A4 Drug-drug interactions involving CYP3A4 Acute coronary syndrome Acute coronary syndrome Diabetes mellitus/insulin resistance Diabetes mellitus/insulin resistance Elevated body mass index Elevated body mass index Genetic Factors Polymorphisms of CYP Polymorphisms of GPIa Polymorphisms of GPIa Polymorphisms of P2Y 12 Polymorphisms of P2Y 12 Polymorphisms of GPIIIa Polymorphisms of GPIIIa Clopidogrel Response Variability Angiolillo DJ et al. J Am Coll Cardiol. 2007; 49:

ACC/AHA/SCAI 2005 Guideline Update for PCI Oral Antiplatelet Adjunctive Therapies In patients in whom subacute thrombosis may be catastrophic or lethal (unprotected left main, bifurcating left main, or last patent coronary vessel), platelet aggregation studies may be considered and the dose of clopidogrel increased to 150 mg per day if less than 50% inhibition of platelet aggregation is demonstrated. IIIaIIbIII C Adapted from Smith SC Jr, et al. Available at:

* >50% ADP (20  mol/L)-induced post-treatment platelet reactivity Type 2 diabetes mellitus patients with coronary artery disease on aspirin (81 mg) + clopidogrel (75 mg) therapy for ≥1 month Platelet function assessment to identify suboptimal and optimal responders Study Time Point 1 Platelet function assessment Study Time Point mg clopidogrel/day for 30 days (n=20) 75 mg clopidogrel/day for 30 days (n=20) Randomization Not eligible for randomization Platelet function assessment Study Time Point 2 75 mg clopidogrel/day for 30 days Inclusion Criteria Optimal responders Suboptimal responders * OPTIMUS Study: (Optimizing anti-Platelet Therapy In diabetes MellitUS) Angiolillo DJ et al. Circulation. 2007;115:

T1T2 T1 P=0.5 P< mg 150mg T2 P=0.32 P= ±9 67.4±6 52.3± ±7 Angiolillo DJ et al. Circulation. 2007;115: Primary Endpoint: Maximal ADP (20  mol/L) Platelet Aggregation Maximal ADP (20  mol/L) platelet aggregation (%) OPTIMUS Study: (Optimizing anti-Platelet Therapy In diabetes MellitUS)

OPTIMUS Prevalence of Patients Reaching Therapeutic P2Y 12 Target Levels (20  mol/L-induced Agg max ≤50%) 75 mg 150 mg Agg max >50% Agg max ≤50% 100%40% 60% Angiolillo DJ et al. Circulation. 2007;115: %

CILOSTAZOLPLACEBO p< OPTIMUS-2 P2Y 12 reactivity index (PRI) Impact of Cilostazol on P2Y 12 inhibition in T2DM on aspirin and clopidogrel therapy (%) Angiolillo DJ et al. TCT 2007

What’s in the pipeline????

ASCET trial (ASpirin non-responsiveness and Clopidogrel Endpoint Trial)

Tailoring Treatment with Tirofiban in patients showing Resistance to aspirin and/or Resistance to clopidogrel Patients with stable, unstable low risk CAD undergoing elective PCI being ASA and/or clopidogrel resistance using Verify Now Patients with stable, unstable low risk CAD undergoing elective PCI being ASA and/or clopidogrel resistance using Verify Now SHBD Tirofiban PlaceboPlacebo Double blind 1:1 N=250 pts 3T/2R3T/2R

GRAVITAS Design DESIGN: Prospective, randomized, 3-arm, multi-center trial of tailored antiplatelet therapy after DES. OBJECTIVE: To evaluate whether clopidogrel dose-adjustment based on the VerifyNow P2Y12 assay reduces thrombotic events after DES implantation. PRINCIPAL INVESTIGATOR Matthew J. Price, MD Scripps Clinic La Jolla, CA DESIGN: Prospective, randomized, 3-arm, multi-center trial of tailored antiplatelet therapy after DES. OBJECTIVE: To evaluate whether clopidogrel dose-adjustment based on the VerifyNow P2Y12 assay reduces thrombotic events after DES implantation. PRINCIPAL INVESTIGATOR Matthew J. Price, MD Scripps Clinic La Jolla, CA 7800 Patients with successful implantation of DES at 50 sites in US and Canada Pre-Discharge VerifyNow Platelet Function Assessment 30d, 6M, and 1 yr Clinical FU R 150mg/day75mg/day 30 day VerifyNow Assessment NonRespResp 75mg/day Primary Endpoint: 6-mo CV Death, Non-Fatal MI, ARC definite/prob ST 150mg/day75mg/day

DrugTypeRouteActionDose Mean platelet inhibition (time required) (time required)Trials (phase III) Prasugrel(CS-747) Thienopyridine (3 rd generation) - requires hepatic conversion to active metabolite Oral Irreversible binding 60 mg loading dose, 10 mg maintenance dose ≈ 70% (< 1 hour) TRITON Cangrelor(ARC MX) ATP analogue- Direct inhibition Parenteral Competitive binding 4 μg/kg/min ≈ 95% (few minutes) CHAMPION AZD-6140 Cyclopetyl- triazolopy- rimidine- Direct inhibition Oral Competitive binding 90 mg/twice daily ≈ 95% (2-4 hours) PLATO Novel P2Y 12 ADP receptor antagonist More potent and less variability!! Angiolillo DJ et al. J Am Coll Cardiol Better Clinical Outcomes??

Take Home Messages Variability in individual response to antiplatelet therapy is a true phenomenon and has clinical implications. UNSOLVED ISSUES HOW and WHEN to measure antiplatelet drug responsiveness? WHAT do we do with the results coming from the “test tube”? (No demonstration of an association with clinical events conditioning cost-effective changes in treatment).

Responsiveness to antiplatelet therapy should be evaluated for investigational purposes only!!!!! Conclusions