Treating Minimal Residual Disease in Acute Leukemias: How low should you go?

Treating Minimal Residual Disease in Acute Leukemias: How low should you go? Ramsie Lujan, Pharm.D. PGY1 Pharmacy Practice Resident Methodist Hospital, San Antonio, Texas Pharmacotherapy Education and Research Center The University of Texas Health Science Center at San Antonio November 7, 2014 Learning Objectives 1. Define minimal residual disease 2. Describe the techniques for measuring minimal residual disease 3. Analyze studies demonstrating minimal residual disease as a prognostic factor 4. Evaluate current literature on minimal residual disease in acute lymphoblastic leukemia and acute myeloid leukemia 5. Discuss current strategies for treating minimal residual disease

Acute Leukemia I. What is acute leukemia? 1 A. Acute leukemia: Cancer that begins in blood-forming tissue, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the bloodstream. 1 The word "acute" refers to the disease s rapid progression and creation of immature blood cells, rather than mature ones. 2 i. Consist of two categories a) Acute myeloid leukemia (AML): clonal proliferation of myeloid precursors with a reduced capacity to differentiate into more mature cellular elements 1,4 b) Acute lymphoblastic leukemia (ALL): malignant transformation of B or T cell progenitor cells. It is the most common cancer in children but can occur at any age 1,3 ii. Figure 1: Demonstrates the lineage of both ALL and AML. 1,2 II. Traditional assessment of acute leukemia 1 A. Goal: achieve complete remission (CR) i. Complete remission is defined as: a) <5% leukemia cells (blasts) in the bone marrow b) Normal hematopoiesis a. absolute neutrophil count >1,000 cells/µl, platelets >100,000 cells/µl, red blood cell transfusion independence c) No other signs or symptoms of disease R. Lujan Page 2

B. Prognostic factors for acute leukemias 3,4,5 i. Table 1: AML 3,5 ii. Table 2: ALL 4,6 C. Treatment outline: 3,4,7 i. Initial therapy for both AML and ALL patients is termed induction therapy. The goal is to induce complete remission. ii. Following induction, patients in remission receive consolidation/maintenance chemotherapy to eliminate remaining leukemic clones R. Lujan Page 3

iii. Figure 2: Illustrates the treatment algorithm for leukemia patients D. Evaluating response to chemotherapy i. Bone marrow aspirate and biopsy examined microscopically and analyzed for leukemic blasts ii. Pathologist counts the leukemic cells a) If <5% = CR b) If >5% = refractory or relapsed disease Minimal Residual Disease (MRD) I. Why is minimal residual disease important? 8 A. AML i. 70-80% of adult patients will achieve a CR ii. 60-70% of patients in CR will relapse B. ALL i. 85-90% of adult patients will achieve a CR ii. 40-50% of patients in CR will relapse C. Relapse is associated with a poor survival rate II. What is minimal residual disease (MRD)? 8 Residual leukemic cells detected using molecular techniques after treatment is completed. MRD can be assessed following induction and/or consolidation/maintenance III. How is MRD measured? 9-14 A. Two main assays are used to measure MRD i. Flow cytometry (FC): Detects abnormal immunophenotypes R. Lujan Page 4

a) In normal cells, antigens present in a constant and reproducible pattern. Leukemic cells can have increased or decreased antigens in an aberrant pattern b) FC integrates three systems: fluids, optics and electronics a. Fluids carry particles in front of a laser (optics) b. A signal is sent to electronics to produce a picture c) Detection capability: 0.01-0.1% d) Does not always distinguish leukemic cells from normal hematopoietic cells. Increased number of targets increases specificity. ii. Polymerase chain reaction (PCR): amplifies leukemia specific DNA (if present) a) Heat is used to split DNA strands a. DNA primers are added b. DNA polymerase synthesizes new strands of DNA starting from primers c. DNA target is amplified millions of times b) Detection capability: 0.00001-0.01% B. Table 4: FC vs. PCR 8 C. Table 5: Summary of traditional vs. minimal residual disease assessment 1 R. Lujan Page 5

Clinical Significance of MRD I. MRD as a prognostic factor: literature review (Tables 6 and 7) Citation Trial Design Objectives Inclusion Criteria Exclusion Criteria GENERAL STUDY OVERVIEW (Table 6) Buccisano F, Maurillo L, Gattei V et al. The kinetics of reduction of minimal residual disease impacts on duration of response and survival of patients with acute myeloid leukemia. Leukemia. 2006; 20:1783 89. 16,17 Randomized, prospective trial Determine the effect of MRD on clinical outcome and correlate MRD with other recognized prognostic factors, such as multidrug resistance 1 (MDR1) phenotype and cytogenetic findings METHODS Diagnosis of AML with expression of leukemia-associated phenotype; eligibility for intensive chemotherapy; achievement of a morphologic CR after induction therapy Patients who did not achieve CR after induction, less than 18 years of age Interventions Patients ages 18-60 entered into EORTC/GIMEMA AML-10 group Induction with cytarabine, etoposide and anthracycline; consolidation with cytarabine & same anthracycline as induction Patients ages >60 entered into EORTC/GIMEMA AML-13 group Induction with mitoxantrone, etoposide and cytarabine; consolidation with cytarabine, etoposide and idarubicin Outcome Measures Relation between MRD and response to treatment relation between the level of MRD after consolidation and time to relapse Overall survival (OS) and relapse free survival (RFS) Statistics Response to treatment was assessed with use of a 2-sided t-test or Fisher exact test. A p-value of < 0.05 was considered significant. RESULTS Enrollment 56 patients enrolled, baseline characteristics only available in 49 out of 50 Outcomes Conclusion 5-year probability overall survival(os): Post induction therapy: MRD + vs. MRD - : 25% vs. 51% (P=0.017) Post consolidation therapy: MRD + vs. MRD - : 16% vs. 61% (P <0.001) Relapse free survival (RFS): Post induction: MRD + vs. MRD - : 7 vs. 12 month median relapse (P=0.01) Post consolidation: MRD + vs. MRD - : 10 vs. 15 months median relapse (P<0.001) 5-year probability of RFS Post induction: MRD + vs. MRD - : 22% vs. 51% (P=0.003) Post consolidation: MRD + vs. MRD - : 13% vs. 71% (P<0.001) MRD is an independent variable that significantly correlates with OS and RFS R. Lujan Page 6

Citation Trial Design Objectives Inclusion Criteria Exclusion Criteria Interventions Outcome Measures Statistics Enrollment Outcomes Conclusion GENERAL STUDY OVERVIEW (Table 7) Gokbuget N, Kneba M, Raff T, et al. Adult patients with acute lymphoblastic leukemia and molecular failure display a poor prognosis and are candidates for stem cell transplantation and targeted therapies. Blood. August 30, 2014;120:1868-76. 18 Prospective, risk stratified trial Evaluate the prognostic effect of molecular response within risk groups defined according to conventional prognostic factors and the outcome of patients with molecular failure. METHODS Patients with BCR-ABL negative ALL, ages 15-55 years old Patients BCR-ABL positive ALL, < 15 or > 55 years old Standard risk(sr): Patients who did not meet below criteria High risk(hr): WBC count >30,000/µL in B-lineage ALL, pro-b-all, early or mature T-cell ALL, MLL-AF4/t(4;11) translocation, or no achievement of cytologic CR after induction Treatment: All patients received intensive 7-drug induction therapy with phase 1 and 2, followed by one uniform consolidation that was mainly based on high-dose methotrexate and high-dose cytarabine, starting at day 71 SR group received further consolidation HR group were candidates for allogeneic stem cell transplants MRD measured: Days 11, 26, 46, 71, week 16, and at further time points during consolidation < 0.001% = MRD negative Cytologic response = looked at blast in the bone marrow (traditional assessment) 5-year probability of continuous CR and overall survival (OS) Categorized variables were compared with the chi square test and medians with the Wilcoxon test to estimate significant differences. Survival analysis was performed with the Kaplan-Meier method. A p-value of < 0.05 was considered significant. RESULTS 1648 patients enrolled from 130 centers 5-year probability of continuous CR Standard risk group: o MRD - vs. MRD + : week 16 was 70% vs. 12% (P <0.0001) 5-year probability of overall survival (OS) High risk group: o MRD - vs. MRD + : 81% vs. 33% (P <0.0001) MRD is an independent variable that significantly correlates with continuous CR and OS R. Lujan Page 7

II. MRD as a prognostic factor: A. Standard framework for risk stratification is largely based off pre-treatment prognostic factors B. Minimal residual disease is an independent prognostic factor. MRD negative individuals have increased RFS and OS C. The optimal time to measure MRD is post consolidation therapy D. Implementation of MRD measurement is challenging because of technological and quality control issues Utilization of MRD I. Possible utilization of MRD: A. Identify patients at high risk for relapse and refer for allogeneic hematopoietic stem cell transplant (allo-hsct) earlier i. Traditionally, patients are transplanted in the second CR B. Decrease intensity of therapy C. Use MRD as an endpoint to evaluate treatment efficacy II. Literature review (Tables 8 and 9) Citation Trial Design Objectives Inclusion Criteria Exclusion Criteria Interventions GENERAL STUDY OVERVIEW (Table 8) Zhu H, et al.mrd-directed risk stratification treatment may improve outcomes t(8;21) AML in the first complete remission: results from the AML05 multicenter trial. Blood. May 16, 2013;121:4056-62. Prospective, non-randomized, multicenter cohort study We aimed to improve the outcome of t(8;21) AML in the first complete remission (CR1) by applying risk-directed therapy based on MRD determined by RUNX1/RUNX1T1 transcript levels. METHODS Newly diagnosed AML (ages 14-60) with t(8;21), in CR after 2 induction cycles and no contraindications to consolidation therapy or allogeneic hematopoietic stem cell transplant (Allo-HSCT) Previously diagnosed AML patients, < 14 or > 60 years old Low risk (LR): patients who achieved major molecular remission (MMR) after the second consolidation and maintained MMR for >6 months High risk (HR): patients who did NOT achieved MMR after the second consolidation or did not maintain MMR for >6months Used these categories to direct therapy (risk directed therapy) MMR: 3-log reduction in RUNX1/RUNX1T1 transcripts (<0.4%) compared with the pretreatment R. Lujan Page 8

Outcome Measures Statistics Enrollment Outcomes Treatment: Induction: 1-2 cycles of 7 +3 Consolidation: 1-2 cycle of IDAC with or without anthracycline Allogeneic HSCT Primary outcome: Relapse rate and disease free survival (DFS) Overall power of 80% for a 2-sided test to detect a difference of 25% between the 2 groups, assuming that 1 group had a relapse rate of 45%. Survival analysis was performed with the Kaplan-Meier method. A p-value of < 0.05 was considered significant. RESULTS 137 patients enrolled from three centers in Beijing Relapse rate: DFS: Allo-HSCT vs. chemotherapy for HR patients o Cumulative incidence of relapse (CIR)- 22.1% vs 78.9% (P<0.0001) Allo-HSCT vs. chemotherapy for LR patients o CIR- 14.7% vs. 5.3% (P=0.33) Allo-HSCT vs. chemotherapy for HR patients o DFS- 61.7% vs. 19.6% (P=0.001) Allo-HSCT vs. chemotherapy for LR patients o DFS- 70.3% vs. 94.7% (P=0.024) Risk directed vs. guideline based therapy o DFS- 74.7% vs. 53.1% (P=0.01) Conclusion MRD risk directed therapy improved relapse rate and DFS. Citation Trial Design Objectives GENERAL STUDY OVERVIEW (Table 9) Vora A, Goulden N, Wade R et al. Treatment reduction for children and young adults with low-risk acute lymphoblastic leukaemia defined by minimal residual disease (UKALL 2003): a randomised controlled trial. The Lancet. February 7, 2013;14:199-209 Prospective, randomized controlled trial To determine whether adjustment of treatment intensity according to MRD risk stratification is feasible METHODS Inclusion Criteria Children and young adults diagnosed with BCR-ABL negative ALL (ages 1-24) Exclusion Criteria Patients <1 or patients with mature B-cell ALL and/or BCR-ABL (+) Interventions Patients stratified according to initial clinical risk of relapse using: National Cancer Institute (NCI) risk criteria Early response to induction R. Lujan Page 9

Patients were assigned 1:1 to treatment groups Patients were categorized by MRD after induction Low Risk(LR): MRD <0.01% at the end of induction and before maintenance High Risk (HR): MRD >0.01% at the end of induction Outcome Measures Statistics Enrollment Outcomes Conclusion Treatment: MRD - : One (reduced) or two (standard) delayed intensifications MRD + : standard or an intensive schedule (additional chemotherapy) Primary outcome: Event free survival (EFS) Secondary outcomes: cumulative risk of relapse, overall survival, and treatment related toxic effects Overall power of 80% with a one-sided p-value. P-value <0.05 considered significant. RESULTS 3092 patients enrolled from 45 centers in the UK and Ireland 5-year EFS MRD low risk group (reduced vs. standard treatment) o 94.4% vs. 95.5% (CI: -5.6-2.5) MRD high risk group (intensive vs. standard treatment) o 98.5% vs. 97.9% (CI: 0.19-2.3) Improvement of EFS when compared to benchmark UKALL 99 study All patients with 11.5% improvement MRD + group benefited most with 12% improvement in 5 year probability of EFS vs. NCI high risk group Demonstrates that a reduction of post-remission treatment for low risk patients does not affect EFS III. Table 10: Summary of Zhu and Vora et al R. Lujan Page 10

IV. Ongoing Trials: 30,31 A. Gruppo Italiano Malattie E Matologiche dell'adulto: i. Purpose: Assess MRD directed therapy for newly diagnosed AML and OS ii. Design: Open label, parallel assignment iii. Estimated completion date: July 2016 B. Peking University People's Hospital i. Purpose: Evaluate the efficacy of interferon-alpha in transplant patients using MRD as the endpoint ii. Design: Open label, single assignment trial iii. Estimated completion date: July 2016 Summary I. MRD is an independent prognostic factor II. MRD should be used to stratify therapy A. First CR and/or after consolidation B. Could support decisions for or against transplant III. Ongoing trials are utilizing MRD to tailor treatment Remaining Questions I. What number of abnormal cells should be used to define MRD status? II. How does the information gained from MRD testing differ among various ALL subtypes? A. T cell versus B cell ALL, Philadelphia chromosome positive ALL III. What is the best test to measure MRD? IV. Generalizability of MRD testing between different hematological malignancies? R. Lujan Page 11

References 1. National Cancer Institute at the National Institutes of Health. Leukemia. Available from: http://www.cancer.gov/cancertopics/types/leukemia. Accessed on November 1, 2014. 2. Mayo Clinic. Acute Lymphocytic Leukemia. Available from: http://www.mayoclinic.org/diseasesconditions/acute-lymphocytic-leukemia/basics/definition/con-20042915. Accessed on November 1, 2014. 3. National Cancer Institute at the National Institutes of Health. Adult Acute Lymphoblastic Leukemia Treatment. Available from: http://www.cancer.gov/cancertopics/pdq/treatment/adultall/healthprofessional. Accessed on November 1, 2014. 4. National Cancer Institute at the National Institutes of Health. Adult Acute Myeloid Leukemia Treatment. Available from: http://www.cancer.gov/cancertopics/pdq/treatment/adultall/healthprofessional. Accessed on November 1, 2014. 5. Uptodate. Classification of Acute Lymphoblastic Leukemia. Available from: http://www.uptodate.com/contents/classification-of-acute-myeloid leukemia?source=search_result&search=acute+myeloid+leukemia+adult&selectedtitle=1%7e150. Accessed on October 5, 2014. 6. Uptodate. Classification of Acute Myeloid Leukemia. Available from: http://www.uptodate.com/contents/classification-of-acute-myeloid leukemia?source=search_result&search=acute+myeloid+leukemia+adult&selectedtitle=1%7e150. Accessed on October 5, 2014. 7. Medscape. Acute Myelogenous Leukemia Treatment & Management. Available from: http://emedicine.medscape.com/article/197802-treatment#aw2aab6b6b8. Accessed on October 6, 2014. 8. Campana D. Minimal Residual Disease Studies in Acute Leukemia. Am J Clin Pathol. 2004;122(Suppl 1):S47-S57. 9. Bassan R, Hoelzer D. Modern Therapy of Acute Lymphoblastic Leukemia.J Clin Oncol. 2011;29:532-43. 10. Campana D and Coustan-Smith E. Detection of Minimal Residual Disease in Acute Leukemia by Flow Cytometry. Cytometry (Communications in Clinical Cytometry). 1991; 38:139 152 11. Integrated Oncology Lab Corp. Flow Cytometry. Available from: https://www.labcorp.com/wps/wcm/connect/intoncologylib/integratedoncology/home/our+services/on cology+testing/flow-cytometry-immunophenotyping-by-flow. Accessed on November 1, 2014. 12. Introduction to Flow Cytometry: A Learning Guide. Available from: http://www.d.umn.edu/~biomed/flowcytometry/introflowcytometry.pdf. Accessed on November 1, 2014 13. Knight Diagnostic Laboratories. BCR-ABL RNA PCR Quantitation for Leukemia. Available from: http://www.knightdxlabs.com/home/test-details?id=bcr-abl+rna+pcr+quantitation+for+leukemia. Accessed on November 1, 2014. 14. Velden V, Hochhaus A, Cazzaniga G et al. Detection of Minimal Residual Disease in Hematologic Malignancies by Real-Time Quantitative PCR: Principles, Approaches, and Laboratory Aspects. Leukemia. 2003;17: 1013 34. 15. NCBI. Polymerase Chain Reaction. Available from: http://www.ncbi.nlm.nih.gov/probe/docs/techpcr/. Accessed on November 1, 2014. 16. Bruggemann M, Raff T, Kneba M. Has MRD Monitoring Superseded Other Prognostic Factors in Adult ALL? Blood. November 29, 2012;120:4470-4481. R. Lujan Page 12

17. Buccisano F, Maurillo L, Gattei V et al. The Kinetics of Reduction of Minimal Residual Disease Impacts on Duration of Response and Survival of Patients with Acute Myeloid Leukemia. Leukemia. 2006; 20:1783 89. 18. Vindetti A, Buccisano F, Del Poeta G et al. Level of Minimal Residual Disease after Consolidation Therapy Predicts Outcome in Acute Myeloid Leukemia. Blood. December 1, 2000;96:3948-52. 19. Gokbuget N, Kneba M, Raff T, et al. Adult Patients with Acute Lymphoblastic Leukemia and Molecular Failure Display a Poor Prognosis and are Candidates for Stem Cell Transplantation and Targeted Therapies. Blood. August 30, 2014;120:1868-76. 20. Zhu H, et al. MRD-Directed Risk Stratification Treatment may Improve Outcomes t(8;21) AML in the First Complete Remission: results from the AML05 multicenter trial. Blood. May 16, 2013;121:4056-62. 21. Vora A, Goulden N, Wade R et al. Treatment Reduction for Children and Young Adults with Low-Risk Acute Lymphoblastic Leukaemia Defined by Minimal Residual Disease (UKALL 2003): a randomised controlled trial. The Lancet. February 7, 2013;14:199-209 22. Spinelli O, Tosi M, Peruta B et al. Prognostic Significance and Treatment Implications of Minimal Residual Disease Studies in Philadelphia-Negative Adult Acute Lymphoblastic Leukemia. Mediterr J Hematol Infect Dis. September 1, 2014;6:Open journal system. 23. Buccisano F, Maurillo L, Ilaria Del Principe M et al. Prognostic and Therapeutic Implications of Minimal Residual Disease Detection in Acute Myeloid Leukemia. Blood. January 12, 2012;119:332-41. 24. Maurillo L, Buccisano F, Ilaria Del Principe et al. Toward Optimization of Postremission Therapy for Residual Disease Positive Patients with Acute Myeloid Leukemia. J Clin Oncol. October 20, 2008;26:4944-51. 25. Estey EH. Acute Myeloid Leukemia: 2014 Update on Risk-Stratification and Management. Am. J. Hematol. 2014;89:1064 81. 26. Forida Y, Mortuza, Papaioannou M et al. Minimal Residual Disease Tests Provide an Independent Predictor of Clinical Outcome in Adult Acute Lymphoblastic Leukemia. Journal of Clinical Oncology. February 15, 2002;20: 1094-1104. 27. Paietta E. Assessing Minimal Residual Disease (MRD) in Leukemia: a Changing Definition and Concept? Bone Marrow Transplantation. 2002;29:459 65. 28. San Miguel JF, Vidriales MB, Lopez-Berges C et al. Early Immunophenotypical Evaluation of Minimal Residual Disease in Acute Myeloid Leukemia Identifies Different Patient Risk Groups and may Contribute to Postinduction Treatment Stratification. Blood. September 15, 2001;98:1746-51. 29. Determination of Minimal Residual Disease in Leukemia Patients. British Journal of Haematology. 2003; 121:823 38. 30. Gruppo Italiano Malattie E Matologiche dell'adulto. Risk-adapted, MRD-directed Therapy for Young Adults With Newly Diagnosed Acute Myeloid Leukemia. GIMEMA Protocol AML1310. EudraCT Number 2010-023809-36. Available from: http://clinicaltrials.gov/ct2/show/nct01452646?term=gruppo+italiano+malattie+e+ematologiche+dell% 27Adulto&rank=11. Accessed on October 29, 2014. 31. Huang XJ et al. Interferon α for the Therapy of Minimal Residual Disease Following Hematopoietic Stem Cell Transplantation. Available from: http://clinicaltrials.gov/ct2/show/nct02185261?term=minimal+residual+disease&rank=2. Accessed on November 3, 2014. R. Lujan Page 13

R. Lujan Page 14