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M inimal R esidual D isease in AML. Steven M. Kornblau, M.D. Department of Leukemia Department of Stem Cell Transplantation and Cellular Therapy. The MRD Concept. Most patients achieve remission Most relapse Cure rate 20-25% overall therefore 2/3 rd relapse
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Minimal Residual Disease in AML Steven M. Kornblau, M.D. Department of Leukemia Department of Stem Cell Transplantation and Cellular Therapy
The MRD Concept • Most patients achieve remission • Most relapse • Cure rate 20-25% overall therefore 2/3rd relapse • What if we could predict who will eventually relapse ? • Could we act on this information to benefit the patient?
Goals for MRD • Residual disease detectable at some time point • When? • Which marker? • MRD detection adds prognostic information to presentation features • Should not be something measureable at diagnosis • A threshold that predicts relapse vs. CCR can be defined • What level is actionable? • There is a therapeutic response that can be taken • MRD detected more or different therapy • Not detected less therapy needed, less toxicity. • Serve as a surrogate marker for efficacy?
Barriers to MRD in AML • Defined marker to follow not always present • Cytogenetics • Mutations • Flow • Standardized methodology not available • Standardized threshold not defined • Continuous variables measured, dichotomized endpoints desired. • A therapy that will improve things may not exist. Co-occurrence is frequent creates added complexity When multiple events are present which do you follow? Are effects: Additive, cancel each other out, synergistic?
Methods for MRD detection • Multiparameter flow • limit of detection 1:10-4 • More rapid • RT-PCR • limit of detection varies by assay, target gene etc. • Experimentally on cell lines “spiked” 1:10-3 to 10-7 • Practical on patient samples 1:10-4 to 10-5 • Takes longer • Good markers PML-RARα, NPM1, MLL, CEPBA, WT1 EVI1(Mecom) PRAME • Normal Marrow will give a positive signal for nearly all mutations at some level • Regenerating marrows are not the same as “Normal” marrows • Literature often incorrectly uses “sensitivity” when they mean the “limit of detection” or “lowest possible threshold” Hokland Blood 2011; 117:2577-84
When to monitor for MRD? • One time • When? • Immediately post induction • at CR1, at 3 month? …. • Serially • Starting when? • How often? • Repeat in ~ 2 weeks • Same or Rising Consider as molecular relapse Act ? • Down or gone, repeat in 2 weeks How to respond to (conversion ) MRD? Hokland Blood 2011; 117:2577-84
Problems with using mutations • Variation in mutation site, insertion site, length • Multiclonality at DX or relapse • Expansion of minor clones • Mutation status can change between DX and relapse • Mutational shift e.g. FLT3-ITD • Loss or gain of mutations • Instability can affect usefulness of these markers for MRD • Use of Next Generation Sequencing to follow clonal evolution over time. Probably u$eful but expen$ive.
Kinetics of relapse affect frequency of monitoring and source SLOWER FASTER NPM1 NPM1-WT & FLT3-ITD NPM1-mut & FLT3-ITD PML-RARα WT1 RUNX1 CBFB-MYH11 Monitor with: Peripheral Blood Bone Marrow
MRD in APL- Take Home • PML/RARα measured by Quantitative RT-PCR is Standard of care • for all or just high risk? • After induction • ATRA & Anthracycline -useless due to residual apoptotic and differentiated cells • ATO – Any positive is bad • After consolidation it is clearly bad • Conversion to positive predicts relapse. False positive is rare • Rising PCR at rate of 1 log per month predicts relapse. • Outcome better if treated after conversion instead of waiting for relapse • ATRA + Chemo era: PETHEMA Leukemia 2007, 21:446-52 • Arsenic Era: Grimwade , JCO 2009, 27:3650-8 & Leuk Res 2011;35:3-7 • Affects quality of Autograft , if MRD positive don’t use (GIMEMA) • Persistent positive can be salvaged by allograft. • Sequential monitoring. • Follow the Eur Against Ca program (Leukemia 2003, 14:2318-57) • Marrow better than blood. 1.5 Log more sensitive. • Q 3 month for 36 mopost consolidation • Economically advantageous $4-11K/QALY
APL Treated with ATO alone 151 patients treated with ATO single agent. 2 step Nested Q-PCR, used BIOMED-1 methods, Quantified by Eur Against Ca protocols Sensitivity 10-3 after 1st round, 10-4 after 2nd round Ct = PML-RARα/ABL * 100 Negative if beyond 40 20.5% relapsed, median 15 mo %+ 100 63% 18% 0% RR 4.8 NS Sensitivity 86.7% Specificity 42.3% Lead time provided by detection of conversion 31 relapses 15 > 4 months 10 never pos 6 not done False Positive conversion 4.6% (8/151) Chendamarai Blood v119:3143 2012
How much lead time? Did it matter? • AML N=79, Median age 42.5 (20-67), Standard TX • Frequent monitoring by RQ-PCR • median 74 samples PER patient!, range 10-237 • but not set schedule over 6-60 months. • Fusion Gene: N=24, CR=23, Molecular CR (PCR-) in 11/24 • Molecular relapse N=33 in 17 patients • 12 Not treated at PCR conversion . 100% relapsed. • Median lead time was 25.5 days, range 8 to 79 days • 21 treated at molecular relapse (N=12 patients) Chemo, GO, DLI • CR= 7 molecular PR=7 No response =8 • 4 “cured” 8 Relapse, Median 119 days • PB and BM- strongly correlated (R= 0.8) • Whole BM and CD34+ and CD34- strong correlation (R=.9) • Pre-emptive therapy salvaged ~33%, delayed relapse 66%. • Doubek (ExpHem2009;37:659-672)
CBFβ AML • False Positive rare in inversion 16 • qRT-PCR -Standardized Europe Against Cancer assay ratio w.r.t. β2M • 53 with inversion 16, age 16-60 • 13 samples per patient, blood vs. BM, • Diagnosis, Induction cycle #1 and #2, • Consolidation #1,2,3, • Follow up 3 6 9 12 15 18 24 36 72 mo • Marrow more sensitive • Pre TX correlated with % BM blasts, not other clinical features • Kinetics of decline after induction did not correlate with outcomes • After consolidation 59% negative, 2Yr RFS 70% in neg vs. 54% positive • 14 Positive, 10 relapsed- they never achieved negativity (Median 1190) • 35 negative, 3 relapsed, 2 converted to >10 copies • Follow Up- 29 Neg at some point, 10 converted, 6 of these relapsed. Lead times were 3, 5 , 6mo for 3, but 3 others at relapse. During Consolidation Early Follow-up Early Follow-up Corbaciaglu JCO 28:3724-3729 2010
Wilms Tumor 1 • Overexpressed in 90% of AML, mutated ~ 10% • Phase I- tested 9 RQ-PCR protocols in 11 labs, cut 3 • Phase II tested 6 in 11 labs, selected best 3 • Phase III tested 3 protocols on several standards, picked the best • Established reference from normals-Often Expressed • 118 PB, 61 BM , 25 G-CSF stim PB • Tested • Diagnosis 238 PB, 382 BM, 15 with WT1 mutation • After Anthra+ ara-C therapy N=129, 16 repetitively • Results • Blood = BM at Dx and MRD • Mutant = wild type • High levels in Inv16, FLT3itd, NPM1 Magnitude of decline after induction predictive, >2 log Level after consolidation also predictive Cilloni JCO 2009;27:5195-5201
NPM1 • Potentially a great target as 30% mutated • 17 different mutations measured by PCR. • Type A= 80%, B ,D = 6% each • Limit of detection 1:10,000 to 1:100,000 • 252 NPM1 mutated AML followed 84 relapsed • 47 MRD+ 15-221 days (median 62) before relapse • 15 never MRD- Failure to get 3 log reduction = relapse • 31 MRD never + before relapse • All relapses had the same NPM1 mutation • Sensitivity = 62/93 =66%, • Specificity? Not stated. • Many time points prognostic • Prognostic after Allo SCT Schnittger Blood 2009;114:2220-31
Multiparameter Flow Cytometry • Only 50% have suitable molecular markers for PCR • 80-94% have a flow detectable pattern • Leukemia Associated ImmunoPhenotype, define at diagnosis • “Different from Normal” define at diagnosis • Gives a quantitative result • When to assess? • What threshold to use? • Ranges used from 0.035 to 1% • 0.1% commonly chosen. • No predictive benefit using 0.01% (Leung Blood 2012;120:468-472) • How many cells to analyses? • Clusters of as few as 20 cells can define MRD • 200,000 events 1:10:000 = 20 cells • Recommended to study 1 million as not all blast express the pattern. • Almost all studies use levels derived retrospectively and lack a validation cohort. • See Ossenkoppele Br J Haem 2011;153:421-436 for review of literature
The Leukemia Associated ImmunoPhenotypeVs. the “Different from Normal” approach • Must detect the LAIP at the time of DIAGNOSIS to follow later • May be more than one LAIP • Must follow all of them to pick out minor clones that expand. • Different from Normal -Use a panel of ab and look for characteristic pattern. • Asynchronous expression very useful. E.g CD34+ and CD123+ • Lineage infidelity useful. E.g. CD7 (Lymphoid) expression on AML blasts • Aberrant expression associated with cytogenetic abnormalities • AML1-ETO : CD19+, CD11a- CD56+/- cCD79a = poor prognosis • CBFβ –MYH11: CD2+ • T(15:17) : CD56 in 20%= bad • NPM1: CD13, CD117 CD110 CD123 • CEBPA: 7+ • S&S best with 6+ color flow, Abs to LSC & multiple lymphoid Ags • Leukemia Stem Cell frequency • CD34+ CD38- CD123 CLL-1 CD44 CD47 CD96 & the same aberrant markers. • Low frequency can be a disadvantage
Multiparameter Flow Cytometry Potential Problems • Background = expression on normal cells • limits both sensitivity & specificity, • Can raise limit of detection to 0.1% to 1% • Background lower in PB vs. BM • Not all blasts express the aberrant marker • Lowers sensitivity • Immunophenotype shifts- can be as high as 91% • Most cases have multiple LAIPs reducing the false negative rate. • But looking for the diagnostic pattern will miss newly emergent patterns • Flow subject operator expertise • Standardized protocols and automated analyses may help • SchuurheisExpert Rev Hem 2010;3:1-5)
LSC by FLOW for MRD • CD34+CD38- & • Positive for CD123 CD117 CD25 • Negative for HLA-DR • Frequency at diagnosis predictive of relapse • Persistence after therapy predictive of relapse • Rarity make BM better than blood • Rarity might decrease sensitivity • Aberrant markers exist • C-type lectin like (CLL-1), not seen on normal
MRD by Flow in Adults AML >1% • 233 consecutive Adults • Median age 42+ 18 • Cytogenetics • Fav n=49 (Includes 43 APL) Int = 35 Unfav =10 Unk=32 • 3 color + FSC, SSC at diagnosis and remission. • 15K event followed by live gate on larger # of cells • Looked for SAME phenotype as at diagnosis 175 aberrant IP 126 CR with 3+7 x 2 + HDAC+ anthra x 2 16 to Auto SCT 12 to Allo >0.1% >0.01% <0.01% >0.01% >0.1% >1% San Miguel Blood 2001;98;1746-51
MRD By Flow adds to cytogenetics Survival % in Remission MRD - • Favorable & Intermediate cytogenetics • But not to unfavorable or FLT3-ITD • FLT3 WT • MRD+ adds • FLT3-ITD • Doesn’t add MRD + MRD - MRD + Buccisano Blood 2012;119(2);332-341
Summary of Studies of Prognostic Value of MPFC in AML Ossenkoppele Gr J Haem 2011:153;421-436
MRD in Pedi AML- AML02 Study • Induction 1 with high vs. low dose ara-C + Dauno and etoposide • MRD#1 on day 22, if >1% positive then immediately to induction 2, otherwise wait for recovery of counts then to induction 2 • Induction 2 ADE +/- Gemtuzumab-ozogamicin • MRD#2 by Flow measurement after 2ndindution • Low HDAC x 3. Good cyto more often negative • High Allo (n =59). Bad cyto more often positive • 216 AML enrolled 202 evaluable for MRD #1, 193 for MRD#2 • Use of high dose ara-C no effect. Use of GO increased conversion to MRD- MRD most powerful in multivariate CBF, 11q23 and FLT3 stay in the model Triage to ALLO didn’t seem to help the high risk group
Does early intervention in CR1 help ? • Chemotherapy. • Delayed but didn’t prevent • More trials underway • Pedi- Clofarabine + ara-C for MRD >0.1% • Adults • Ceplene + low dose IL2 • Anti CD33-gemtuzumab • Dendritic cell vaccination • Azacitidine or Decitabine • Allo SCT- questionable benefit • Adults • Walter JCO 2011; 29:1190-97 • Pedi • Rubnitz. Lancet Oncology 2010;11:534-552 • WT1 Jacobson Br J Haem 2009:146:2709-16 • Leung Blood 2012; 120:468-72
MRD Post ALLO SCT • Rise in MRD presages relapse • Follow a molecular marker if available • Change in Chimerism: • Ratio recipient to donor, especially in CD34+ cells • VernerisCurr Het Malig Rep 2010;5:157-162 • Rapid dynamics of relapse makes MRD use difficult • Hypomethylating agent can be beneficial • Platzbecker Leukemia 2012;26:381-89 • Azacitadine75mg/m2/day for 7 days. Median 4 (1-11 ) cycles • N=20 • 16 50% increasing donor chimerism , 30% stable • Despite this 13 relapsed Median @ 231 days • Bolanos-Meade Biol Blood Marrow Transplant 2011;17(5) 754-758 • Azacitadine75mg/m2/day for 7 days. • N= 10 • Best BM response = CR in 6, 3 progressed, 1 revert to MDS • 2 CR got DLI, 1 developed cGVHD • 4 CR lost all host chimerism 2 with MRD • 1 relapsed • Median survival = 422 Days
MRD- Meeting the goals? • Detectable Markers Yes • Definable thresholds Yes, but variable • Prognostic Yes • Action improves Outcome? • APL Yes • Molecular relapse after Allo Yes for 30-40% • All others Not Yet…
MRD- what is needed • Standardized assays and cutpoints • Prospective studies to validate • Multicenter • Multiple central labs • Clinical studies demonstration that action based on MRD improves outcome • Markers needed for poor prognosis AML • New Therapies that work