Treating Higher-Risk Myelodysplasia Current Concepts: Etiology, Clinical Manifestations, and Treatment Gary Schiller, MD Presentations in Two Patients 86 y.o. male with a 6-y hx of macrocytic anemia referred for a fall in hgb from 10 to 8g/dl requiring monthly transfusion-support. P.E. without significant findings. P.B.: WBC12.7, Hgb 8.7 MCV 95.1, Plt 282K; BM showed RARS, karyotype: 45,X,-Y[2] 46,XY[18] 53 y.o. male with a 1-m hx of fatigue referred for evaluation of pancytopenia. P.E. revealed splenomegaly. P.B.: WBC 2.4, Hgb 7.2, plt 49K; BM showed RAEB, karyotype: 47,XY,+8[11]/46,XY[9] Myelodysplasia- Definition Catenacci DVT, Schiller, G: Blood Rev. 2005 An oligoclonal disorder of hematopoiesis characterized by: Ineffective hematopoiesis Cytopenias Variable clonal cytogenetic abnormalities Variable tendency toward evolution to acute leukemia Page 1
Pathophysiology Bone Marrow Microenvironment Increased pro-apoptotic signals- soluble factors» TNF-α, VEGF Dysregulation of immune response» Over-expression of HLA-D15 Genomic Instability of the Clone Jackson et al., Nature 2002 Lachner, Current Biology 2002 Cytogenetic Abnl Distinct Cytogenetic Findings Olney HJ, LeBeau MM: Best Practice & Res. Clin. Haem. 14:479-95; 95; 2001 Percent of MDS/t- MDS Risk of progression to AML/prognosis Region of chromosome involved/gene Del 20 q 5% / 7% Low/ good Gene-rich CDS 20q11.2-q12 Monosomy Y - Low if isolated/good Monosomy 5/5qdel 10-20% / 40% High/poor Two separate CDS regions Monosomy 7/del7q 5% / 55% High/poor 7q22 and 7q32-33 17p- 7% MDS High/poor Tumor-suppressor p53 11q23 5-6%/ 2-3% Intermediate/med. MLL gene Trisomy 8 10% MDS Intermediate/med. Unknown Complex karyotypes 10-20% / 90% High/poor Multiple 5 q - syndrome Low/good Q 31 and q 333 Page 2
Bone Marrow Findings in MDS Erythropoiesis Megaloblastic; nuclear cytoplasmic asynchrony Nuclear atypia of erythroid precursors» Budding nuclei, multi-lobed, multinuclear, etc. Ringed sideroblasts» Abnormal iron distribution/utilization Megakaryopoiesis Micromegakaryocytes Nuclear atypia» Mononuclear; multiple small nuclei Bone Marrow Findings in MDS Granulopoiesis Hyposegmented granulocytic precursors Psuedo Pelger-Huet cells Hypogranular granulocytes Loss of orderly maturation» maturation bulge = maturation arrest Abnormal increase in blasts Classification of MDS FAB classification WHO classification Page 3
Prognosis in MDS Shortened survival Infection Bleeding Progression to AML FAB categories poorly predict prognosis Recognizes role of excess blasts in determining outcome Wide range of outcomes/survival in each group Neglects role of cytogenetics, cytopenias Unclassifiable MDS Prognosis in MDS Identification of additional risk factors International Prognostic Scoring System Blasts Cytogenetics Cytopenias Survival Evolution to AML Cytogenetics Acquired chromosomal abnormalities are found in 40-60% of primary MDS patients Abnormalities in 80% of therapy-related MDS Alkylators induce multiple abnormalities, particularly in chromosomes 5 and 7 Topoisomerase inhibitors induce MLL gene fusions, usually involving 11q23 Page 4
International Prognostic Scoring System Points Marrow Blasts < 5% 0 5-10% 0.5 11-20% 10 1.0 21-30% 1.5 Cytopenias 0 or 1 0 2 or 3 0.5 Cytogenetics good (normal; 5q-; Y-; 20q-) 0 intermediate (others) 0.5 poor (7; or >3 abnormalities) 1.0 International Prognostic Scoring System Overall Score Median Survival Low Risk 0 5.7 years Intermediate-1 0.5-1.0 Intermediate-2 1.5-2.0 High Risk > 2.5 3.5 years 1.2 years 0.4 years International Prognostic Scoring System Overall Score Evolution to AML Low Risk 0 9.4 years Intermediate-1 0.5-1.0 Intermediate-2 1.5-2.0 High Risk > 2.5 3.3 years 1.1 years 0.2 years Page 5
Treatment of Myelodysplasia-- Difficulties in Assessing the Data Paucity of randomized trials Endpoints Cytopenias, transfusion requirement Survival Trial populations Age Prognostic group Baseline studies Inclusion of de novo AML Myelodysplasia Treatment Curative approaches Transplantation Disease control Low intensity therapy High intensity therapy Supportive care Hematopoietic growth factors Transfusion Antibiotics Iron chelation Risk-Adapted Therapy in Myelodysplastic Syndromes Appropriately identify and treat different subcategories of disease Identify high-risk disease in patients who are candidates for aggressive therapy Allogeneic stem cell transplant Cytotoxic chemotherapy Prognosticate Improve complications and quality of life Page 6
Intensive Chemotherapy in MDS Combination chemotherapy AML remission induction regimens» 3 + 7 (anthracycline + cytarabine) with or w/out etoposide» Topotecan with or w/out cytarabine» Fludarabine with cytarabine» Decitabine in clinical trials <50% remission rates» 90% of patients relapse» Co-morbid disease Remission durations < 1 year» Bridge to autologous transplant Suitable for young patients Stem Cell Transplantation Myeloablative therapy High-dose chemotherapy + radiation Rescue infusion of hematopoietic stem cells Bone marrow Peripheral blood (apheresis) Umbilical cord blood Stem Cell Transplantation in Myelodysplasia Allo SCT outcome correlates with IPSS score 251 patients with MDS, FHCRC 5 year disease-free survival» 60% for low risk and intermediate-1 t» 36% for intermediate-2» 28% for high risk Allo SCT for intermediate or high risk patients Appelbaum & Anderson. Leukemia 1998;12 (Suppl 1): S25- S29 Autologous stem cell transplant Recovery of polyclonal hematopoiesis in some cases Page 7
Stem Cell Transplantation in Myelodysplasia Benefit (survival) exceeds risk for IPSS intermediate or high risk patients who are physiologically suitable for allogeneic transplant Non-myeloablative transplant Fludarabine, TBI preparative regimen Decreased regimen-related mortality Up to age 75 Azacytidine in Myelodysplasia Silverman LR, Demakos EP, Peterson BL et al. J Clin Oncol. 2002;20:2429 RNA and DNA methylation inhibitor given subcutaneously in monthly cycles Response rate and Survival compared to best- supportive care with potential to cross-overover Response Rate 23% vs. 0% Complete remission in 7% Response Duration 15 months with time-to-response of 64 days Diminished rate of transformation to AML but improvement in survival not significant Azacitidine: DNA Hypomethylation and Gene Activation DMT A : T C : G G : C mc : G G Aza C : C m DMT D M T A za A : T C : G G : C C : G G : C Azacitidine inhibition of DNA methyltransferase (DMT) results in hypomethylation. Hypomethylation may restore normal function to genes critical for differentiation and proliferation. Silverman, LR. The Oncologist. 2001;6(suppl 5):8-14. Page 8
Study 9221 A Randomized Phase III Controlled Trial of Subcutaneous Azacitidine in Myelodysplastic Syndromes RA RARS RAEB RAEB-T CMML S t r a t i f y No R 1) Supportive Exit a Care* Criteria + n Yes d o m i 2) Aza C 75mg/m z 2 /d x 7 days q28 x 4 e Continue until Endpoint + Aza C (dose as per arm #2) A S Response - Continue Rx S E No Response S - Off Study S M M M 0 29 57 113 * Minimum duration of supportive care = 4 months unless Day M = Bone Marrow transform to AML; death or plts < 20 x 10 9 /L at week 8 or later Silverman L. The Oncologist 2001. 6 (S5): 8-14. Silverman LR, et al. J Clin Oncol. May 2002;20(10):2429-2440. Kornblith AB, et al. J Clin Oncol 2002. 18:2427-39 Aza C Azacitidine S.C. Study 9221: Study Design A randomized, open-label, phase III study comparing the safety and efficacy of subcutaneous VIDAZA (azacitidine for injectable suspension) plus supportive care, versus supportive care alone 53 US sites Patients with any of the 5 FAB subtypes of MDS were included in the study. Patients with AML diagnosis were excluded from analysis (N=19). For purposes of assessing efficacy, the primary endpoint was response rate (CR+PR) Per protocol, patients achieving complete response (CR) with VIDAZA therapy were to receive 3 additional treatments before completing the study. VIDAZA full prescribing information. Study 9221: VIDAZA (azacitidine for injectable suspension) Dosing 75mg/m 2 SC daily x 7 days Cycles should be repeated every 4 weeks Recommended starting dose for the first treatment cycle, regardless of baseline hematology laboratory values is 75mg/m 2 SC daily for 7 days Dose could be increased to 100 mg/m 2 if no beneficial effect was observed after two treatment cycles, and no toxicity other than nausea and vomiting Premedicated for nausea and vomiting Page 9
Gender (n%) Male Female Race (n%) White Black Hispanic Asian/Oriental Age (years) N Mean ± SD Range Study 9221: Baseline Demographics Azacitidine (N=99) 72 (72.7) 27 (27.3) 93 (93.9) 1 (1.0) 3 (3.0) 2 (2.0) 99 67.3 ± 10.39 31-92 Observation (N=92) 60 (65.2) 32 (34.8) 85 (92.4) 1 (1.1) 5 (5.4) 1 (1.1) 91 68.0 ± 10.23 35-88 Study 9221: Baseline Characteristics Azacitidine (N=99) Observation (N=92) Adjudicated MDS diagnosis at study entry (n%) RA 21 (21.2) 18 (19.6) RARS 6 (6.1) 5 (5.4) RAEB 38 (38.4) 39 (42.4) RAEB-T 16 (16.2) 14 (15.2) CMMoL 8 (8.1) 7 (7.6) AML* 10 (10.1) 9 (9.8) Transfusion product used in 3 mos before study entry (n%) Any transfusion product 70 (70.7) 59 (64.1) Blood cells, packed human 66 (66.7) 55 (59.8) Platelets, human blood 15 (15.2) 12 (13.0) * Not intended to be included Study 9221: Additional Endpoints Improvement Benefit in peripheral counts not meeting criteria for PR Patients achieving at least a single lineage response defined as:» 50% restoration in the deficit from normal of baseline WBC, hemoglobin, or platelets (if abnormal at baseline) or» 50% reduction in PRBC or platelet transfusion requirements VIDAZA Transfusion requirements (azacitidine for injectable suspension) full prescribing information. Data on file, Pharmion Corporation. Page 10
Study 9221: Response Rates* VIDAZA (azacitidine for injectable suspension (N=89) Observation before Crossover (N=83) Response n (%) n (%) p-value Overall (CR+PR) 14 (15.7) 0 (0.0) <0.0001 Complete (CR) 5 (5.6) 0 (0.0) 0.06 Partial (PR) 9 (10.1) 0 (0.0) --- *Excludes patients with adjudicated baseline diagnosis of AML Approximately 24% of Vidaza patients were considered improved VIDAZA (azacitidine for injectable suspension) full prescribing information. VIDAZA (azacitidine for injectable suspension): Proven treatment for MDS patients with excess bone marrow blasts According to the IPSS, excess blasts are the strongest predictor of poor outcomes More than half of all patients who participated in study 9221 had excess blasts prior to treatment Patients with RAEB or RAEB-T responded to VIDAZA therapy, as did those without excess blasts Patients who achieved CR had complete normalization of peripheral and bone marrow blasts Patients who achieved PR had a 50% or greater reduction in bone marrow blasts and no peripheral blasts VIDAZA full prescribing information. Data on file, Pharmion Corporation. Study 9221: Time to Response 90% of responding patients had an increase in platelets, hemoglobin, or WBC, or a decrease in bone marrow blasts by the 5 th cycle Achievement of PR was reported between the 2 nd and 19 th cycles Achievement of CR was reported between the 8 th and 15 th cycles PR or CR may require more than 4 treatment cycles with VIDAZA (azacitidine for injectable suspension) VIDAZA full prescribing information. Data on file, Pharmion Corporation. Page 11
Study 9221: Efficacy Summary Response was independent of FAB subtype Patients with RAEB or RAEB-T responded as did those without excess blasts Approximately half of all responding patients (CR or PR) achieved a trilineage response Responders experienced a decrease in bone marrow blasts, and/or an increase in platelets, hemoglobin, or WBC No overall differences in efficacy were observed between older patients and younger patients Survival benefit or delay in progression to AML, despite persistence of decreased bone marrow blasts percentages during PR or CR, could not be established for VIDAZA (azacitidine for injectable suspension) because cross over of control patients to the active treatment arm confounded these time-to-event end points Decitabine in Myelodysplasia Wijermans P, Lubbert M, Verhoef G, et al. J Clin Oncol. 2000;18:956 Potential Mechanism of Action Inhibition of methylation; targe may be p15 since hypermethylation of p15 is correlated with progression Unique characteristics Dose and Schedule Intravenously over 3 hours every 8 hours for three days each cycle Phase III Decitabine Study Design Open-label, 1:1 randomized, multi-center study in the US and Canada Eligible Patients (n = 170) R A N D O M I Z E D D St tifi ti Stratification IPSS Classification Prior Chemotherapy Study Center Decitabine + Supportive Care* (n = 89) Supportive Care* (n = 81) * Antibiotics, Growth Factors and/or Transfusions Page 12
Decitabine Dose and Administration Schedule: 3 hour infusion q 8 hrs x 3 days Three Consecutive Days 15 mg/m 2 3 hour 15 mg/m 2 3 hour 15 mg/m 2 3 hour 8 hours 8 hours 8 hours Cycle 135 mg/m 2 3 days 6 week cycle Median number of cycles/patient: 3 (Range = 1-9) Response* to Decitabine (ITT) IWG Response Rate, Onset & Duration Decitabine (n = 89) Supportive Care (n = 81) Overall Response Rate (CR+PR) 15 (17%)** 0 (0%) **p-value <0.001 from two-sided Fisher s Exact Test Onset & Duration of Response in Months Median time to (CR+PR+HI) response Median Duration of (CR+PR+HI) response 3.2 (2.0-5.5) 9.5 (4.7-12.4) Best response observed after 2 cycles (median number of cycles = 3) *IWG MDS criteria, Blood 2000 96:3671-3674. Response Rates of Phase 2 and Phase 3 Trials of Decitabine (DAC) in patients with myelodysplastic syndrome abstract 2515 Page 13
Response Rates of Phase 2 and Phase 3 Trials of Decitabine (DAC) in patients with myelodysplastic syndrome abstract 2515 Myelodysplasia- final points. Therapeutic response to novel therapy and the need for new diagnostic groups (Schiller Leukemia 17: 1183-1185; 1185; 2003) Clinical responses occur within a narrow statistical band for a variety of heterogeneous disorders Hematological improvement is typically erythroid Time to response is typically prolonged Response duration is not known Rarely, agents affect transformation, but not survival Future Directions in MDS Monoclonal antibodies Anti-CD33 conjugates Immunotherapy Vaccines Dendritic cells Differentiation therapy Other combination therapies Targeted therapies Must identify molecular targets! Farnesyltransferase inhibition Flt3 antagonists Page 14
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