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FDA Presentation to the Oncologic Drugs Advisory Committee Tositumomab Therapeutic Regimen Corixa Corporation BLA 125011 December 17, 2002. Tositumomab Therapeutic Regimen Review Team. Product/Chairperson: Terrye G. Zaremba, Ph.D. Clinical Reviewers: Stephen Litwin, M.D.
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FDA Presentation to the Oncologic Drugs Advisory Committee Tositumomab Therapeutic Regimen Corixa Corporation BLA 125011 December 17, 2002
Tositumomab Therapeutic Regimen Review Team Product/Chairperson: Terrye G. Zaremba, Ph.D. Clinical Reviewers: Stephen Litwin, M.D. George Mills, M.D. Harvey Luksenburg, M.D. Kaushikkumar Shastri, M.D. Biostatistician: Satish Misra, Ph.D. Pharm/Tox: Martin D. Green, Ph.D. Radiochemistry: Leon Epps, Ph.D. BioResearch Monitor: Mary Andrich, M.D. Facilities Specialist: Deborah Trout, B.S. Project Managers: Karen Jones, B.S. Craig Doty, Pharm. D Michael A. Noska, M.S
SubmissionTime-Line • Sept 14, 2000- BLA 125011 submitted • RIT-II-004- 5/31/2000 study report • RIT-II-000 and 001- final study reports • RIT-II-002 and 003-interim study reports • ISS - 286 subjects • Dec 14, 2000 • CP98-020 interim study report • ISS - 308 subjects
Timeline (2) • March 16, 2001 – FDA Action letter #1 • Multiple requests for info on product characterization and manufacture • Inadequate efficacy database -single pivotal trial with substantially different efficacy in transformed vs. non-transformed, some supportive data submitted as interim reports • Inadequate safety database - substantial missing data for acute heme toxicity and delayed hematologic, thyroid and HAMA events
Timeline (3) • August 27, 2001 • RIT-II-003 second interim report through 12/20/2000 • ISS update – 309 patients • Sept 7, 2001 • Final study report CP97-012 • Amended study report RIT-II-002 - MIRROR panel review, data cut-off Jan. 2001
Timeline (4) • Sept 10, 2001- Corixa response to FDA letter • Dec 11, 2001 • RIT-II-004- amended final study report, data cutoff Jan 2001, MIRROR panel review Sept 2001 • ISS update – 620 patients (includes 387 from expanded access) • Long-term responders- various studies- MIRROR panel review • Additional info for CP98-020
Timeline (5) • March 5, 2002 • ISS update: corrected errors & gave additional hematology data collected from audit at clinical study sites in 620 pts • March 12, 2002- FDA action letter #2 • Need to demonstrate a meaningful therapeutic advance over existing treatment (Zevalin approved Feb. 2002) • Additional safety data needed
Timeline (6) • July 2, 2002 • Case report forms and report tabulations for long-term responder subpopulation • July 11, 2002 • Revised proposed indication • Requested accelerated approval for chemo-refractory and standard approval for Rituximab-refractory pts • Amendment 1 to final study report for CP97-012
Timeline (7) • October 4, 2002 • Amendment 2 to final study report for CP97-012 • October 30, 2002 • Independent review for additional patients with transformed histology in CP 97-012 • October 31, 2002 – Corixa completes response to FDA 3/12/2002 letter
Timeline (8) • December 10, 2002 –Responses to Bi Mo inspectional findings • Outstanding issues on clinical trial • identification of dose delivered vs. dose prescribed for patients in efficacy studies • FDA will need to confirm safety profile of proposed dose
Tositumomab Therapeutic Regimen (TTR)Monoclonal Antibody Characteristics • Tositumomab and I-131-Tositumomab • Tositumomab also called “Anti-B1” • Murine IgG2a, l • Recognizes CD20
Characteristics of CD20 • Transmembrane phosphoprotein with a molecular weight of 33-37 kDa • Present on the surface of pre-B and mature B cells • Expressed on >90% of B-cell lymphomas • Not present on stem cells, mature plasma cells, or other nonlymphoid normal tissues • Is not shed or internalized upon antibody binding
MonoclonalAntibody Characteristics (2) • Manufactured by standard tissue culture and purification techniquees • I-131- Tositumomab radiolabeled by the IODO-GEN® method
TTR Components • Unlabeled: -Tositumomab 3 mL vial: 35 mg @ 14 mg/mL -Tositumomab 20 mL vial: 225mg @ 14 mg/mL
TTR Components (2) • Labeleld (I-131-Tositumomab • Dosimetric vial: not less than 20 mL in a 30 mL vial. Protein concentration between 0.10 and 0.25 mg/mL. Calibrated activity of 12-18 mCi. • Therapeutic vial: not less than 20 mL in a 30 mL vial. Protein concentration between 1.1 and 2.5 mg/mL. Calibrated activity of 112-168
TTR Procedure Step 1 – Imaging • Tositumomab 450 mg in 0.9% NaCl injection in total volume of 50 mL IV over 60 minutes • I-131 Tositumomab (dosimetric) 5 mCi + 35 mg Tositumomab in 0.9% NaCl injection in total volume of 30 mL IV over 20 minutes
TTR Procedure Step 2 - Therapy (7-14 days post imaging) • Tositumomab 450 mg in 0.9% NaCl injection in total volume of 50 mL IV over 60 minutes • I-131-Tositumomab (therapeutic) 35 mg containing the patient-specific dose (mCi) IV over 20 minutes
TTR Procedure • Thyroid protective agent is given beginning at least 24 hours prior to the first infusion of I-131 Tositumomab (dosimetric dose) and continues for 14 days following the last infusion of I-131 Tositumomab (therapeutic dose).
Remaining CMC Issues • A number of manufacturing issues remain to be resolved • One contract facility remains to be inspected