AGGRENOX TM Development Rationale AGGRENOX TM  Development Rationale Head of Haemostasis Laboratory Blood Transfusion Center of the German Red Cross Oldenburg, Germany Thomas Müller, MD, PhD

Haemostatic Repair

Mural Thrombus Formation

BloodSample(anticoagulated) Flow Formation of Platelet Aggregates Platelet Aggregates Form Under Flow on Subendothelial Matrix Müller et al. (1990) Br J Clin Pharmac.

Inhibition of the Growth of All Aggregates Müller et al. (1990) Br J Clin Pharmac. 40 PlaceboER-DP 400 mg/d ASA 50 mg/d ASA/ER-DP 50 mg mg/d Relative Reduction in Mean Area of ALL Thrombi (%) N = 23 N = 22 N = 23 N = 24

Inhibition of the Growth of Very Large Aggregates 2 Placebo ER-DP 400 mg/d ASA 50 mg/d ASA/ER- DP 50 mg mg/d Reduction of VERY LARGE Thrombi Müller et al. (1990) Br J Clin Pharmac.

Mural Thrombus Formation

AA TxA 2 Cyclooxygenase Generates Thromboxane A 2

Weksler B et al. (1985) Stroke. 16:1–9. AA TxA 2 AA ASA Irreversibly Inhibits Cyclooxygenase 40 mg ASA/d in stroke patients X

Collagen Thrombin Thrombin Shear Shear Adrenaline Adrenaline PAF PAF TxA 2 ADP ? Platelet Activation Aggregation Platelet Activation Aggregation X ASA Inhibits Only a Single of Multiple Pathways

Adenosine ADP is Degraded to Adenosine ADP

ADP Adenosine PlateletInhibition X DP Inhibits the Adenosine Uptake IC 50 = 0.25 µg/mL Human Plasma

Extended Release Dipyridamole DP Plasma Plasma Conc. Conc. (µg/mL) (µg/mL) Time (hours)

Summary and Conclusions Dipyridamole and ASA inhibit platelet aggregation by independent mechanisms Doses and formulations Doses and formulations No evidence for pharmacokinetic interaction No evidence for pharmacokinetic interaction

Summary and Conclusions Dipyridamole and ASA inhibit platelet aggregation by independent mechanisms Doses and formulations optimized Doses and formulations optimized No evidence for pharmacokinetic interaction No evidence for pharmacokinetic interaction Combining ASA with DP in AGGRENOX TM Additive inhibition of platelet thrombus formation Additive inhibition of platelet thrombus formation

AGGRENOX TM bid Plasma Conc. (µg/mL) Time (hours) ER Dipyridamole 200 mg bid Mean DP Plasma Levels AGGRENOX TM vs ER Dipyridamole

Development Rationale for AGGRENOX TM DP and ASA extensively studied DP and ASA extensively studied Different mechanisms of platelet inhibition Different mechanisms of platelet inhibition – Pharmacokinetic implications – Additive platelet inhibition – Without increased bleeding

Aspirin Inhibition of platelet activation and aggregation Mechanisms of Action COX AdenosinePDE Dipyridamole

cGMP GMP EDRF PlateletInhibition Bult H et al. (1991) Thromb Haemostas. 66:343–9. DP Inhibits the cGMP-Phosphodiesterase IC 50  0.8 µg/mL X

Mean Salicylate Plasma Levels AGGRENOX TM vs ASA Source: Brickl et al (U ) Time (h) AGGRENOX™ bid Aspirin 25 mg bid Concentration (µg/mL)

Conclusions AGGRENOX TM PK / PD ER-DP provides sufficient DP plasma levels over the entire 12 h dosing interval ER-DP provides sufficient DP plasma levels over the entire 12 h dosing interval ASA and ER-DP DO NOT have a PK interaction ASA and ER-DP DO NOT have a PK interaction

Mural Thrombus Formation

Stroke Reduction in ESPS-2 (%) Reduction of Very Large Aggregates (%) DP ASA D+A Antithrombotic Efficacy vs Inhibition of Very Large Platelet Aggregates +

Placebo 4.5 DP ER4.7 ASA8.2 Aggrenox TM 8.7 Diener et al, J Neurological Sciences. ESPS-2 Frequency of Bleeding %

Summary and Conclusions AGGRENOX  combines two extensively studied drugs: ASA and DP AGGRENOX  combines two extensively studied drugs: ASA and DP Each component inhibits platelet aggregation by independent mechanisms Each component inhibits platelet aggregation by independent mechanisms –Doses and formulations optimized –No evidence for pharmacokinetic interaction

Summary and Conclusions Combining ASA with DP in AGGRENOX  Combining ASA with DP in AGGRENOX  – Additively inhibits platelet aggregation – Does not increase bleeding

What is the Scientific Rationale for AGGRENOX TM ? DP and ASA both effective in preventing arterial thrombosis DP and ASA both effective in preventing arterial thrombosis DP and ASA widely used; safety profile well-defined DP and ASA widely used; safety profile well-defined Differing mechanisms of action for inhibiting platelet aggregation and thrombosis effects should be additive Differing mechanisms of action for inhibiting platelet aggregation and thrombosis – effects should be additive

Mechanisms of Action AspirinDipyridamole Inhibition of platelet activation and aggregation Inhibits cyclooxygenase & thromboxane A 2 Increases plasma adenosine Inhibits platelet phosphodiesterase

Hours DP Concentration (  g/mL) Blood Concentration of DP vs Extended-Release DP 4 x 100 mg/day (instant release) 2 x 200 mg/day (extended release) Doses administered at arrows Repeated Dosing in Volunteers Goal is to maintain plasma level at or above 1 Goal is to maintain plasma level at or above 1µg/ml

Time [h] Inhibition of Platelet Cyclooxygenase by ASA 56 mg b.i.d. 100 mg b.i.d. 178 mg b.i.d. 316 mg b.i.d.     mg b.i.d. 10 mg b.i.d. 32 mg b.i.d. 18 mg b.i.d.

Secondary Prevention of Stroke: Aspirin Relative risk reduction for TIA, stroke, and/or death FDA analysis:  13% to 18% (21 CFR ) FDA analysis:  13% to 18% (21 CFR ) Algra and van Gijn 1996 (Meta-analysis of 10 studies): 14% Algra and van Gijn 1996 (Meta-analysis of 10 studies): 14% Lanes 1998 (Meta-analysis): 15% Lanes 1998 (Meta-analysis): 15%

Relative Risk Reductions for Vascular Death, Stroke, MI from ASA Trials vs Placebo All  100 UK-TIA All  %0.640%0.820%10%1.2-20%1.4-40%1.6-60% RR and 95% CI ASA  100 mg ASA  900 mg ASA 300 mg ALL Algra and van Gijn (1996) J Neurol Neurosurg Psychiatr. 60: Algra and van Gijn (1996) J Neurol Neurosurg Psychiatr. 60:197–199. RR = 13% RR = 9% RR = 14% RR = 13%

Optimal Dose Combination of Dipyridamole With Aspirin Maintain DP plasma level at or above 1mg/mL Achieved with 200 mg extended release DP b.i.d. Achieved with 200 mg extended release DP b.i.d. Provide ASA at dose that will inhibit platelet cyclooxygenase with minimal inhibition of endothelial cyclooxygenase Appropriate cyclooxygenase inhibition achieved with doses of 18 to 25 mg ASA b.i.d. Appropriate cyclooxygenase inhibition achieved with doses of 18 to 25 mg ASA b.i.d.

Optimal Dose Combination of DP with ASA 10:18:1 1:1 Inhibition of Thrombus 4:1 Maintain dose ratio at 8:1 (DP:ASA) or higher Maintain dose ratio at 8:1 (DP:ASA) or higher

Pharmacokinetic Considerations Additive inhibitory effects cannot be realized if ASA and DP negatively interact Additive inhibitory effects cannot be realized if ASA and DP negatively interact Small, clinically insignificant differences seen in AUC and peak concentration of DP and ASA when administered in combination Small, clinically insignificant differences seen in AUC and peak concentration of DP and ASA when administered in combination Pharmacokinetics of combination support independent action of each agent Pharmacokinetics of combination support independent action of each agent

Immediate Release Dipyridamole DP Plasma Plasma Conc. Conc. (µg/mL) (µg/mL) Time (hours) IR 75 mg tid

Reduction in Platelet Aggregation After Four Days of Treatment PlaceboER-DPASAASA/ER-DP Relative Reduction in Mean Area (%)

Secondary Prevention of Stroke: Previous Findings DP + ASA: Relative risk reduction for stroke Combination never adequately tested prior to ESPS-2 Combination never adequately tested prior to ESPS-2 Previous studies found no significant effects (sample sizes too small; lacked adequate power) Previous studies found no significant effects (sample sizes too small; lacked adequate power) Meta-analyses suggest DP + ASA more effective than ASA alone (Lowenthal, 1994; Stachenko, 1991; Sze, 1988) Meta-analyses suggest DP + ASA more effective than ASA alone (Lowenthal, 1994; Stachenko, 1991; Sze, 1988)

15% 23% 34% 9% 15% 38% NF Stroke/Death Fatal/NF Stroke DP + ASA ASARRR ESPS-1: Main Results ITT Analysis Percent

How ESPS1 Provided Guidance for the Design of ESPS-2 Results of ESPS-1 demonstrated utility of DP and ASA in combination Results of ESPS-1 demonstrated utility of DP and ASA in combination Several important questions unanswered Several important questions unanswered –Contribution made by each of the active agents (DP and ASA) compared with the combination drug to the overall observed efficacy –Efficacy of low-dose ASA