1. Overview of Methotrexate Clinical Evaluations Malcolm Smith, MD, PhD Cancer Therapy Evaluation Program National Cancer Institute FDA Pediatric ODAC Meeting - March 2006

2. 50 Years of Randomized Trials Evaluating Methotrexate for ALL Acute Leukemia Group B trial Acute Leukemia Group B trial Remission induction with prednisolone and vincristine, followed by randomization.Remission induction with prednisolone and vincristine, followed by randomization. Comparison of 3 mg/m 2 daily oral MTX versus 30 mg/m 2 twice-weekly IV MTXComparison of 3 mg/m 2 daily oral MTX versus 30 mg/m 2 twice-weekly IV MTX Median CR duration: 17 months versus 3 months favoring IV MTXMedian CR duration: 17 months versus 3 months favoring IV MTX 50 years later still trying to learn how to use methotrexate 50 years later still trying to learn how to use methotrexate JAMA 194: 187-193, 1965

3. Complexities of Studying Methotrexate Standardizing high-dose methotrexate? Standardizing high-dose methotrexate? 1 gm/m 2 over 24 hours (POG),1 gm/m 2 over 24 hours (POG), 2 gm/m 2 over 24 hours (Dutch)2 gm/m 2 over 24 hours (Dutch) 5 gm/m 2 over 24 hours (BFM)5 gm/m 2 over 24 hours (BFM) 8 gm/m 2 over 24 hours (NOPHO)8 gm/m 2 over 24 hours (NOPHO) Optimal timing of leucovorin rescue? Optimal timing of leucovorin rescue? 36 hours? 42 hours? 48 hours?36 hours? 42 hours? 48 hours? Number of courses of high-dose methotrexate (from 1 to 12)? Number of courses of high-dose methotrexate (from 1 to 12)? Capizzi escalating dose methotrexate and role of asparaginase “rescue”? Capizzi escalating dose methotrexate and role of asparaginase “rescue”?

4. Childhood ALL Collaborative Group Overview – Methotrexate Efficacy Meta-analysis: 8 randomized trials asking an IV MTX (+/-) question of therapy Meta-analysis: 8 randomized trials asking an IV MTX (+/-) question of therapy MTX doses from 0.5 gm/m2 to 8 gm/m2 MTX doses from 0.5 gm/m2 to 8 gm/m2 Addition of IV MTX to long-term IT therapy or radiotherapy with IT therapy reduced event rate by 17% Addition of IV MTX to long-term IT therapy or radiotherapy with IT therapy reduced event rate by 17% IV MTX reduced non-CNS relapse rate IV MTX reduced non-CNS relapse rate No effect of IV MTX on CNS relapses No effect of IV MTX on CNS relapses Clarke, et al. J Clin Oncol 21:1798-1809. 2003

5. Childhood ALL Collaborative Group Overview – IV Methotrexate Efficacy Clarke, et al. J Clin Oncol 21:1798-1809. 2003

6. Recent Methotrexate Randomized Studies – POG-9005 B-precursor ALL – Standard risk B-precursor ALL – Standard risk IV MTX 1.0 gm/m 2 versus PO MTX 30 mg/m 2 every 6 hours for six doses IV MTX 1.0 gm/m 2 versus PO MTX 30 mg/m 2 every 6 hours for six doses CCR rate superior for IV MTX compared to PO MTX (p=0.013) CCR rate superior for IV MTX compared to PO MTX (p=0.013) Caveat: Too much leucovorin in the PO MTX arm?? Caveat: Too much leucovorin in the PO MTX arm?? Mahoney, et al., J Clin Oncol, 16: 246-254, 1998

7. Recent Methotrexate Randomized Studies – POG-9404 T-cell ALL & lymphoblastic lymphoma T-cell ALL & lymphoblastic lymphoma Addition of IV MTX 5.0 gm/m 2 to consolidation therapy Addition of IV MTX 5.0 gm/m 2 to consolidation therapy 3 EFS (SE) of 72.2% (SE 6.7%) vs. 86.0% (SE 5.6%) for the No HD-MTX and HD- MTX groups 3 EFS (SE) of 72.2% (SE 6.7%) vs. 86.0% (SE 5.6%) for the No HD-MTX and HD- MTX groups Primary difference in arms for CNS events Primary difference in arms for CNS events Caveat: Delay of radiation in no HD-MTX arm may have increased CNS event rate for control patients Caveat: Delay of radiation in no HD-MTX arm may have increased CNS event rate for control patients Asselin, et al. Proc Am Soc Clin Oncol 20, Abstr #1464. 2001

8. Recent Methotrexate Randomized Studies – CCG-1882 & CCG-1961 Evaluated “Capizzi methotrexate” during “interim maintenance” as per “augmented” BFM regimen: Evaluated “Capizzi methotrexate” during “interim maintenance” as per “augmented” BFM regimen: MTX escalating from 100 mg/m 2 q 10 days x 5MTX escalating from 100 mg/m 2 q 10 days x 5 Asparaginase 24 hours after MTXAsparaginase 24 hours after MTX Vincristine q 10 days x 5Vincristine q 10 days x 5 CCG-1882: Improved outcome for SER patients with augmented BFM compared to standard interim maintenance CCG-1882: Improved outcome for SER patients with augmented BFM compared to standard interim maintenance CCG-1961: Improved outcome for the “augmented” strategy with RER patients CCG-1961: Improved outcome for the “augmented” strategy with RER patients Caveat: Augmented BFM differs from standard COG BFM in ways other than “Capizzi methotrexate”. Caveat: Augmented BFM differs from standard COG BFM in ways other than “Capizzi methotrexate”. Seibel, et al. Blood 102 (11), Abstr #787, 2003 Nachman, et al., N.Engl.J.Med., 338: 1663-1671, 1998

9. Recent Methotrexate Randomized Studies – EFS for CCG-1961 Years Followed 5 Yr EFS RHR Augmented BFM 80.5% Baseline Standard BFM 70.7% 1.42 Log rank p =.01 Seibel, et al. Blood 102 (11), Abstr #787, 2003

10. The Question of the Day In 2006, what is the best way to administer MTX during the post- remission, pre-maintenance phase of therapy???? In 2006, what is the best way to administer MTX during the post- remission, pre-maintenance phase of therapy????

11. ALL0232 Treatment Schema

12. Standard ALL Treatment Schema INDUCTION CONSOLIDATION INTERIM MAINTENANCE DELAYED INTENSIFICATION MAINTENANCE 8 week treatment block: Capizzi MTX: IV 100 mg/m 2 MTX q10d x 5 VCR q10d x 5 PEG-Asparaginase x 2 High-dose Methotrexate 5 gm/m 2 MTX x 4 VCR X 4 6MP x 56 days

13. ALL0232 for High-Risk B-Precursor ALL 2 x 2 factorial design using an augmented intensity BFM backbone. 2 x 2 factorial design using an augmented intensity BFM backbone. Activated December, 2003 Activated December, 2003 Approximately 2000 randomized patients to enroll in 4+ years of accrual Approximately 2000 randomized patients to enroll in 4+ years of accrual Randomization 1: Dexamethasone 10 mg/m 2 /d x 14 days versus prednisone 60 mg/m 2 /d x 28 days during Induction Randomization 1: Dexamethasone 10 mg/m 2 /d x 14 days versus prednisone 60 mg/m 2 /d x 28 days during Induction Randomization 2: HD-MTX (5 gm/m 2 ) block versus Capizzi escalating methotrexate block during Interim Maintenance I. Randomization 2: HD-MTX (5 gm/m 2 ) block versus Capizzi escalating methotrexate block during Interim Maintenance I.

14. ALL0434 for T-cell ALL 2 x 2 factorial design using an augmented intensity BFM backbone. 2 x 2 factorial design using an augmented intensity BFM backbone. To be activated in 2nd Quarter 2006 To be activated in 2nd Quarter 2006 Approximately 1200 randomized patients to enroll in 6 years of accrual Approximately 1200 randomized patients to enroll in 6 years of accrual Randomization 1: +/- nelarabine during the Consolidation, Delayed Intensification and Maintenance phases of therapy. Randomization 1: +/- nelarabine during the Consolidation, Delayed Intensification and Maintenance phases of therapy. Randomization 2: HD-MTX (5 gm/m 2 ) blocks versus Capizzi escalating methotrexate blocks during Interim Maintenance I. Randomization 2: HD-MTX (5 gm/m 2 ) blocks versus Capizzi escalating methotrexate blocks during Interim Maintenance I.

15. Potential Mediators of Methotrexate- Associated Neurotoxicity Vezmar, et al. Chemotherapy, 49: 92-104, 2003

16. Methotrexate Neurological Toxicity Acute neurological toxicity (e.g., seizure) with HD-MTX Acute neurological toxicity (e.g., seizure) with HD-MTX Acute neurological toxicity can also be observed with low-dose oral MTX (Winick, et al. JNCI, 84: 252-256, 1992 ) Acute neurological toxicity can also be observed with low-dose oral MTX (Winick, et al. JNCI, 84: 252-256, 1992 ) Chronic neurological toxicity severity ranges from severe leukoencephalopathy to subtle findings on neuropsychological testing Chronic neurological toxicity severity ranges from severe leukoencephalopathy to subtle findings on neuropsychological testing With BPCA support, evaluation of neurological toxicity to become an important secondary objective of both AALL0232 and ALL0434 With BPCA support, evaluation of neurological toxicity to become an important secondary objective of both AALL0232 and ALL0434

17. Summary Despite more than 50 years of evaluation and treatment refinements, important questions remain to be addressed about how best to use methotrexate for children with ALL. Despite more than 50 years of evaluation and treatment refinements, important questions remain to be addressed about how best to use methotrexate for children with ALL. Future use of methotrexate should be based on data from phase 3 trials evaluating both efficacy and neuropsychological endpoints. Future use of methotrexate should be based on data from phase 3 trials evaluating both efficacy and neuropsychological endpoints.