Optimization of Generx (Ad5FGF-4) Clinical Trial Design for Refractory Angina: Interim Results of the Phase 3 ASPIRE Trial Gabor M Rubanyi, MD. PhD. Angionetics Inc., San Diego, CA ASGCT, New Orleans, LA May 15, 2015
Significant Medical Need Exists in Refractory Angina Pectoris 900,000 patients in the US have no or poor existing therapeutic options (Mukherjee et al, 1999; Losordo et al, 2013) 20% of the approximately 1 million angina patients who undergo angiographic evaluation a year have no large coronary artery disease (<70% stenosis) (Vermeltfort et al, 2010): Microvascular Angina (e.g. Cardiac Syndrome X) No-Option Patients : Need New Treatment Paradigm
Therapeutic Angiogenesis: The use of angiogenic growth factors (recombinant proteins or genes) to expedite and/ or augment collateral artery development in myocardial or hind-limb ischemia to improve blood flow and function. J.M. Isner et al., JCI 1994, 93:662-670
Coronary Collateral Network Well-developed Collateral Network Poorly-developed Collateral Network Well-developed Coronary Collateral Network Reduces Stress-Induced Myocardial Ischemia Downstream of Large Artery Narrowing
Benefits of Coronary Collaterals in Heart Disease Well developed coronary collateral network (CFI>0.25) is associated with reduced: - Myocardial ischemia (Steg et al, 2010) - Infarct size (Habib et al, 1991) - CV mortality (Meier et al, 2007) - All-cause mortality (Meier et al, 2012)
However Only 20-30% of patients with CAD (Seiler, 2010) and 50% of patients with refractory angina (Yetkin et al, 2015) have well-developed coronary collateral network
Therapeutic Modalities for Stimulation of Coronary Collateral Growth Mechanical (ECP) Protein Therapy (VEGF,FGF) 2011 Cardium Therapeutics, Inc. Gene Therapy Cell Therapy
Gene and Cell Therapy Clinical Trials in Patients with Refractory Angina (ClinicalTrials.gov) Gene Therapy: 1. KAT301 (Phase 1, Ad5VEGF-D, i.m./noga, Finland) 2. VM202 (Phase 1/2, phgf, i.m., ViroMed, South Korea) 3. ASPIRE (Phase 3, Ad5FGF-4, i.c., Cardium, International Trial- Active) 4. AWARE (Phase 3, Ad5FGF-4, i.c., Cardium, US Trial Not Active) Cell Therapy: RENEW (Phase 3, autologous CD34+ cells, Baxter)
ASPIRE Study Product: Ad5FGF-4 Recombinant angiogenic gene transfer product First generation E1-deleted recombinant adenovirus (human serotype 5) Human fibroblast growth factor-4 (FGF-4) transgene driven by CMV promoter Adenovector construct carries the FGF-4 Gene for Cardiac Delivery
Generx [Ad5FGF-4] Clinical Studies Year Study Name Region / County Clinical Study Phase Patient Status Clinical Endpoint Number Patients Recruited 1999 AGENT-1 U.S. Phase 1/2 Dose finding & safety Class 2 3 Angina Exercise Treadmill Time 79 2001 AGENT-2 North America Phase 2a Mechanism of Action Study >9% Reversible Reperfusion Defect SPECT Imaging 52 2004 AGENT-3 North America Phase 2b/3 Class 2 4 Angina Exercise Treadmill Time 300 2004 AGENT-4 Western Europe & South America Phase 2b/3 Class 2 4 Angina Exercise Treadmill Time 252 TOTAL 683
New Insights 1. Mechanism of adaptive functional collateral network formation provided guidance for: a. biological processes to be stimulated b. target sites for product delivery 2. FGF-4 Biology 3. Ad5 Vector and Its Delivery
Dog/Human Single Vessel Disease Pig/Human Multi Vessel Disease van Royen et al., Cardiovasc. Res. 49:543-553, 2001
What Biological Processes to Stimulate and Where? Therapeutic angiogenesis should stimulate / facilitate both angiogenesis and arteriogenesis TA product should reach both the peri-ischemic regions and also pre-existing collaterals
FGF Biology FGF-2 is involved in both arteriogenesis and angiogenesis during adaptive collateral growth FGF-4 has biology similar to FGF-2, but it has a signal sequence, facilitating its paracrine function FGF-2 and FGF-4 stimulate local production of other angiogenic growth factors (VEGF, HGF, PDGF, MCP- 1, NO)
Upregulation of Endogenous VEGF by Ad5FGF-4 in Rabbit Hindlimb Rissanen et al. FASEB J, 17:100-112, 2000
FGF-4 (4 ng/ml) Stimulates the Release of VEGF from Fibroblasts (NHDF) but not from Endothelial Cells (HUVEC) in a Co-Culture System (Essen Biosciences) Rubanyi GM. J Cardiovasc Pharmacol. 64:109-119, 2014
Is Ad5 an Appropriate Vector? Short-term (2-3 weeks) gene expression is ideal for clinical applications in which the goal is to build new biologic structures. (such as) the expression of angiogenic genes in the myocardium to generate new coronary vasculature. Crystal RG, Human Gene Therapy, 25:3-11, 2014
Optimal Route of Ad5 Delivery to the Heart Antegrade Intracoronary Artery Infusion
19
Optimizing Intracoronary Artery Delivery Method to Increase Ad5 Transduction of Cardiac Myocytes
Barriers to Effective Intravascular Delivery of Ad5 Vector to the Heart
Animal Studies: Myocardial Ischemia Enhances Ad5 Gene Transfer Author Species Ischemia Logeart (2001) Rabbit Yes Transfection / Increase Yes, >3500% Yap (2001) Rat Yes, PA occlusion Yes, >1300% Emani (2003) Piglet Yes Yes, >1000% Muhlhauser (1996) Pig No, Normal Pig No Giordano (1996) Pig Ameroid Yes, >1000% Vinten-Johanson (2010) Pig, Infarct Yes Yes, >1000%
Generx Historical Data: Myocardial Ischemia Is Required for Efficacy Pig ameroid model: ischemia during stress AGENT-1: Large inter-patient variability in Ad5 myocardial uptake (0-100%) AGENT-3&4: Efficacy only in patients with more severe disease (CCS Class 3&4, >55 yrs old, limited exercise capacity, women) 23
Transient Coronary Occlusion Pig Study 1. Control i.c. Ad5Luc 2. Double Occlusion 3 Occlusion 5 i.c. Ad5Luc 3 Occlusion 3. Double Occlusion + NTG 3 Occlusion 5 i.c. Ad5Luc 3 Occlusion i.c. NTG
Effect of Two 3-min Coronary Artery Balloon Occlusions (+/- NTG) on Luciferase Expression in Pig Heart (Intracoronary 10e 11 vp Ad5Luc) (n=5) 100 * p<0.05 vs. N.O. * 82.3+39.6 75 Pg Luc / g tissue 50 25 35.9+27.5 0 0.1 No Occlusion Double Occlusion Double Occlusion + NTG Shi et al, Human Gene Therapy 23:204-212, 2012
The ASPIRE Trial A randomized, controlled, parallel group, multicenter phase 3 study to evaluate the efficacy and safety of Ad5FGF-4 using SPECT myocardial perfusion imaging in patients with stable angina pectoris (Similar to AGENT-2)
Changes in Protocol vs AGENT-2 Trial Ad5FGF-4 dose 3x higher (3x10e10 vp; 30x lower than MTD) Modified intracoronary product delivery (similar to that used in pig study) Control group: ongoing standard medication, but no placebo infusion
Patient Population Patients with refractory angina pectoris who are not candidates for coronary interventions and have Reversible Perfusion Defect Size (RPDS) of 9% by SPECT imaging (Poor Collateral Development) Total enrollment: 100 patients (1:1 randomization to Group A (Generx) and Group B (Control))
Primary Clinical Efficacy Endpoint: Change in Collateral-Dependent Myocardial Perfusion Well-developed Collateral Network Poorly-developed Collateral Network Therapeutic Goal: Improve Collateral-Dependent Flow to Reduce Stress-Induced Ischemia (Angina) in Patients with Poorly Developed Collateral Network (RPDS>9%)
AGENT-2 SPECT Clinical Efficacy Endpoint Improvement in Reversible Perfusion Defect Size as Measured by SPECT Imaging Baseline Pre-Generx Treatment 4 Weeks Following Generx Administration 8 Weeks- 77% Improvement in Perfusion (RPDS) Grines et al., JACC 42: 1339-47 (2003)
Secondary Clinical Efficacy Endpoints Angina diary Nitroglycerin use Seattle Angina Questionnaire Clinical assessment of CCS angina class
Clinical Endpoints: Safety Day 0: complications of product administration Week 1, 4 and 8: adverse events clinical laboratory evaluations Long-term follow-up (12 month)
ASPIRE: Generx Infusion Protocol i.c. Ad5FGF-4 5 2 Occlusion 3 Occlusion i.c. NTG (200ug)
ASPIRE Clinical Study Design 9% Reversible Perfusion Defect Size (RPDS) Baseline SPECT Imaging Initial pilot study confirm new delivery method is safe and effective N=10-12 Main Study N = 90 Group A One time Generx Infusion N = 45 Group B Standard of Care N = 45
Pre-Specified Interim Analysis 11 patients completed 8 week protocol: Active (n=7) Control (n=4)
ASPIRE Interim Analysis: Safety No untoward clinical or laboratory findings New product delivery procedure well tolerated
ASPIRE Interim Analysis: Efficacy Primary Endpoint % Improvement in SPECT Reversible Perfusion Defect Size 30.00% 20.00% 10.00% 0.00% -10.00% -20.00% -30.00% -40.00% -50.00% -60.00% +24.4% P<0.05 Generx N=7-51% Control N=4
Summary ASPIRE trial design was optimized based on mechanistic insights and new experimental studies Pre-specified interim analysis confirmed safety of new delivery method and provided encouraging efficacy results Next steps: Completion of ASPIRE trial in Russia and restart of AWARE trial in the US