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DHHS/FDA/CDRH. Circulatory Support Devices Panel. Boston Scientific Corporation TAXUS ™ Express 2 ™ Paclitaxel-Eluting Coronary Stent System P030025 November 20, 2003. DHHS/FDA/CDRH. Overview of Presentation. FDA Review Team Product Description Non-clinical Evaluation
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Circulatory Support Devices Panel Boston Scientific Corporation TAXUS™ Express2™ Paclitaxel-Eluting Coronary Stent System P030025 November 20, 2003 DHHS/FDA/CDRH
Overview of Presentation • FDA Review Team • Product Description • Non-clinical Evaluation • Clinical & Statistical Evaluation • Panel Questions DHHS/FDA/CDRH
FDA Review Team CDRHJennifer Goode, BS, Biomedical Engineer Stephen Hilbert, MD, PhD, Experimental Pathologist John Stuhlmuller, MD, Clinician Heng Li, PhD, Statistician Raju Kammula, DVM, PhD, Toxicologist Lee Schroeder, PhD, Lead Polymer Chemist Carolyn Vaughan, BS, Mechanical Engineer Lisa Kennell, BS, Microbiologist Steve Wood, PhD, Molecular Biologist Walter Scott, PhD, Patient Labeling Kent Berthold, Manufacturing Hesha Duggirala, PhD, Epidemiologist Sybil Wellstood, PhD, Bioresearch Monitoring DHHS/FDA/CDRH
FDA Review Team CDERNallaperumal Chidambaram, PhD, Chemist Angelica Dorantes, PhD, Pharmacokineticist Belay Tesfamariam, PhD, Toxicologist DHHS/FDA/CDRH
Regulatory History • PMA (P030025) filed on June 19, 2003 • Major Deficiency Letter sent to applicant on September 15, 2003 • Applicant began submitting responses on September 30, 2003 • Interactions continue to resolve outstanding non-clinical issues DHHS/FDA/CDRH
Product Description • Combination Product • Express™ balloon-expandable 316L SS stent • Elective: 3.0 to 5.0mm Ø & up to 18 mm in length • Approved September 11, 2002 NOTE: Does not include an indication for “reducing restenosis” • Catheter delivery systems • Express2™ OTW • Express2™ Monorail NOTE: Slightly different design from the Express™ delivery systems used in TAXUS IV trial DHHS/FDA/CDRH
Product Description • Polymer coating • Translute Non-erodible polymer • Drug substance • Paclitaxel – FDA approved • Leveraged initial drug safety data from Drug Master File (Indena S.p.A.) DHHS/FDA/CDRH
Product Description • TAXUS SR • Proposed product to be marketed • 1 g/mm2 slow release formulation • Used in animal trials and TAXUS I, II, and IV • TAXUS MR • 1 g/mm2 moderate release formulation • Used in animal trials and TAXUS II DHHS/FDA/CDRH
Proposed TAXUS™ Stent Matrix & Nominal Drug Dosage Sizes used in TAXUS IV study Nominal polymer dosages (same across all stent diameters) DHHS/FDA/CDRH
Non-Clinical Evaluation • Pharmacology/Toxicity Testing • In vivo (Animal) Testing • ISO 10993 Biocompatibility of stent + polymer only • Stent/Delivery System Integrity Testing • Shelf Life/Stability • Coating Integrity • Sterility & Package Integrity Testing DHHS/FDA/CDRH
Major OutstandingNon-Clinical Issues • Animal study results • Stability/Shelf life • Finalizing protocols and QC specifications with sponsor • Adequate product has been set aside for testing DHHS/FDA/CDRH
Proposed Indications for Use The TAXUS™ Express2™ Paclitaxel-Eluting Coronary Stent Systems (Monorail and Over-the-Wire) are indicated for improving luminal diameter and reducing restenosis for the treatment of de novo lesions < 28 mm in length in native coronary arteries > 2.5 to < 3.75 mm in diameter. DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Stephen L Hilbert MD, PhD Cardiac Support and Prosthetic Devices Branch Center for Devices & Radiological Health DHHS/FDA/CDRH
Animal Model Justification • Normal swine • Comparable vascular and cardiac anatomy • Vessel diameters suitable for the delivery and deployment of the clinical version of the device • Allows for comparison to historical data DHHS/FDA/CDRH
Non-Clinical In Vivo StudiesSpecific Aims • Device handling characteristics • Safety • Device-tissue responses • General healing response • Device-related pathology • Device-specific findings DHHS/FDA/CDRH
Non-Clinical In Vivo StudiesExperimental Design • Deployment to all three coronary arteries • Dual antiplatelet regimen (ASA + clopidogrel) • 72 hours before implantation through implant duration • Targeted artery-to-balloon ratio • 1:1 to 1:1.2 • Implant duration • 28 to 360 days DHHS/FDA/CDRH
Non-Clinical In Vivo StudiesExperimental Design • Stent platforms evaluated • Bare metal stent • Polymer - coated metal stent • Polymer - drug coated metal stent • Drug dose density - 1 ug/mm2 • MR formulation • SR formulation DHHS/FDA/CDRH
Non-Clinical In Vivo StudiesGraded Pathology Assessment • Mural thrombus • Endothelialization • Neointima • Luminal narrowing • Para-strut amorphous material (PAM) • Medial remodeling • IEL disruption • EEL disruption • Inflammatory response DHHS/FDA/CDRH
Non-Clinical In Vivo StudiesMorphometric Measurements • Luminal area • IEL area • EEL area • Neointimal area • Lumen equivalent diameter • Intimal thickness • Medial area • Stent profile • % stenosis DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Applicable to Safety for This PMA • Bare metal stent • Polymer - coated metal stent • Polymer - drug coated metal stent • Safety Margin • MR - 1 ug/mm2 • Overlapping Stents • MR - 1 ug/mm2 • SR - 1 ug/mm2 DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Study Observations • Similarities in findings across stent platforms • Neointimal formation • Endothelialization • No mural thrombosis • Inflammatory response DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Study Observations • Similarities in findings across stent platforms • Medial remodeling • In-growth of fibrous tissue • Loss of smooth muscle cells • Morphometric measurements • Stable EEL and luminal areas • Reflect medial remodeling DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Study Observations • Differences in findings across stent platforms • Qualitative differences • Medial remodeling • PAM • Dystrophic calcification DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Study Observations • Differences in findings across stent platforms • Magnitude of differences associated with: • Release formulation • MR > SR > polymer, bare metal • Segmental Analysis • Overlapping > Non-overlapping DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Summary • Device handling characteristics satisfactory • Device-tissue response is satisfactory • Neointimal formation • Endothelialization • No mural thrombus DHHS/FDA/CDRH
Non-Clinical In Vivo Studies Summary • Device-related pathology • Medial remodeling • PAM appears to be resolving with time through 360 days • Microscopic dystrophic calcification is variably present • Vessel wall remains structurally intact DHHS/FDA/CDRH
Advisory Panel Question Does the combination of 9 month clinical data from the pivotal TAXUS IV (SR formulation) study and the adjunctive data from TAXUS I (SR formulation) and TAXUS II (SR and MR formulations) adequately address the potential concerns raised by the animal studies? DHHS/FDA/CDRH
Clinical Summary John Stuhlmuller, M.D. Interventional Cardiology Devices Branch Center for Devices & Radiological Health DHHS/FDA/CDRH
Clinical Studies • Pivotal Study • TAXUS IV • Supporting Studies • TAXUS I • TAXUS II • TAXUS V • Peri-Approval Study DHHS/FDA/CDRH
Clinical Studies • Pivotal Study • TAXUS IV • Supporting Studies • TAXUS I • TAXUS II • TAXUS V • Peri-Approval Study DHHS/FDA/CDRH
TAXUS IVStudy Design • Prospective, multicenter and blinded • 1:1 randomization to TAXUS™ stent (SR formulation) or EXPRESS™ stent • Stratified Randomization • 6 month post-procedure antiplatelet regimen DHHS/FDA/CDRH
TAXUS IVStudy Design Stent Length (mm) Stent diameter (mm) 2.50 3.00 3.50 16 24 32 Single Stent Use Small diameters (< 3.0 mm) Long lesions (32 mm stent) Large diameters Not available Multiple Stent Use Provisional overlapping for bail-out stenting DHHS/FDA/CDRH
TAXUS IVPatient Outcome Assessment • Effectiveness • Target Vessel Revascularization at 9 months • Safety • MACE • Stent Thrombosis • Vessel wall structure DHHS/FDA/CDRH
TAXUS IV Patient Outcome Assessment Primary Effectiveness Endpoint TAXUS™ Control Difference [95% C.I.] p-value TVR 4.7% (31/662) 12.0%(78/652) -7.3%[-10.2%, -4.3%] 0.0001
TAXUS IV Patient Outcome Assessment Safety Endpoints Safety Endpoint TAXUS Control p-value MACE to 270 days 8.5% (56/662) 15.0% (98/652) 0.0002 Stent thrombosis to 30 days 0.3% (2/662) 0.6% (4/652) 0.4487 Late thrombosis to 270 days 0.6% (4/662) 0.8% (5/652) 0.7513
TAXUS IV Patient Outcome Assessment Safety Endpoints Incomplete Apposition TAXUS™ Control p-value Post Procedure 11.6% (13/112) 6.4% (7/109) 0.2415 To 270 Days 4.0% (4/99) 3.0% (3/100) 0.7209 Paired Data Resolved 6.4% (6/94) 5.4% (5/93) 1.0000 Persistent 3.2% (3/94) 1.1% (1/93) 0.6210 Late Acquired 1.1% (1/94) 2.2% (2/93) 0.6210
Clinical Studies • Pivotal Study • TAXUS IV • Supporting Studies • TAXUS I • TAXUS II • TAXUS V • Peri-Approval Study DHHS/FDA/CDRH
TAXUS IStudy Design • Prospective, randomized, multicenter and blinded clinical feasibility study • A total of 61 patients enrolled at 3 centers in Germany • NIRx Paclitaxel-Eluting Stent (SR formulation) • Primary study endpoints • MACE at 30 days • Angiographic restenosis at 6 months • Follow-up through 2 years completed DHHS/FDA/CDRH
TAXUS IPatient Outcome Assessment • Effectiveness • Persistent drug effect is maintained through 2 years by angiography and IVUS assessments • Safety • Vessel wall remains structurally intact at 2 years • No safety issues noted DHHS/FDA/CDRH
Clinical Studies • Pivotal Study • TAXUS IV • Supporting Studies • TAXUS I • TAXUS II • TAXUS V • Peri-Approval Study DHHS/FDA/CDRH
TAXUS II Study Design • Prospective, randomized, OUS multicenter, and blinded • NIRx Paclitaxel-Eluting Stent • TAXUS II SR Cohort • 267 patients at 28 centers in 12 countries • TAXUS II MR Cohort • 270 patients at 28 centers in 12 countries • Primary study endpoints • MACE at 6 months • Angiographic restenosis at 6 months • Follow-up through 1 year completed DHHS/FDA/CDRH
TAXUS II SR CohortPatient Outcome Assessment • Effectiveness • Clinical benefit maintained at 1 year • Safety • Vessel wall remains structurally intact in the TAXUS arm compared to control arm at 6 months • No safety issues noted DHHS/FDA/CDRH
TAXUS II MR CohortPatient Outcome Assessment • Effectiveness • Clinical benefit maintained at 1 year • Safety • Vessel wall remains structurally intact in the TAXUS arm compared to control arm at 6 months • No safety issues noted DHHS/FDA/CDRH
TAXUS II SR vs. TAXUS II MRPatient Outcome Assessment • Effectiveness • Similar clinical benefit at 1 year • Safety • Similar vessel wall measurements by angiography and IVUS at 6 months • TAXUS II MR provides preliminary clinical evidence of safety margin for SR formulation • No safety issues noted DHHS/FDA/CDRH
Clinical Studies • Pivotal Study • TAXUS IV • Supporting Studies • TAXUS I • TAXUS II • TAXUS V • Peri-Approval Study DHHS/FDA/CDRH
TAXUS V Study Design • Prospective, multicenter and blinded • 1:1 randomization to TAXUS™ (SR formulation) stent or EXPRESS™ stent • Smaller diameters and longer lesions • Single or overlapping stents DHHS/FDA/CDRH
TAXUS VPatient Outcome Assessment • Study remains blinded • 30-day follow-up on 1080 of 1103 patients enrolled to date • Safety • Total of 122 MACE events • 10 episodes of stent thrombosis in 8 patients • Acute-3, subacute-6 and late-1 • No safety issues noted with broader range of stent use DHHS/FDA/CDRH
Clinical Studies • Pivotal Study • TAXUS IV • Supporting Studies • TAXUS I • TAXUS II • TAXUS V • Peri-Approval Study DHHS/FDA/CDRH
TAXUSPeri-Approval Study • Proposed enrollment of 2000 patients • Phase I – 500 patients • Continued Access Protocol under IDE • Assess format and function of web-based registry • Phase II – 1500 patients • Post-approval web-based registry DHHS/FDA/CDRH