Significance Of Minimal Residual Disease Research Articles

Improved Post-Induction Chemotherapy Does Not Abrogate Prognostic Significance of Minimal Residual Disease (MRD) for Children and Young Adults with High Risk Acute Lymphoblastic Leukemia (ALL). A Report From Children's Oncology Group (COG) Study AALL0232

Abstract 1440Improved Post-Induction Chemotherapy Does Not Abrogate Prognostic Significance of Minimal Residual Disease (MRD) for Children and Young Adults with High Risk Acute Lymphoblastic Leukemia (ALL). A Report from Children's Oncology Group (COG) Study AALL0232.Minimal residual disease is one of the strongest prognostic factors in pediatric ALL. COG AALL0232 was a phase 3 randomized trial for patients 1–30 years old with newly diagnosed NCI HR B precursor ALL that used a 2×2 factorial study design comparing dexamethasone (DEX) versus(vs.) prednisone(PRED) during induction, and high dose methotrexate (HD-MTX) vs. Capizzi methotrexate (C-MTX) during interim maintenance 1(IM-1). We previously reported improved event-free survival (EFS) for patients receiving HD-MTX vs. C-MTX (J Clin Oncol 29: 6s, 2011) and for DEX vs. PRED among patients <10 years old randomized to HD-MTX(J Clin Oncol 29: 586s,2011). MRD was measured by 6 color flow cytometry in two central labs (MJB and BLW) to a level of sensitivity of 0.01% at end induction. Patients with >=0.1% MRD at end induction, as well as patients with morphologic slow early response or specific adverse genetic features received intensified therapy including IM-2 and a second delayed intensification, and then had MRD determined at end consolidation, (about 13 weeks post diagnosis). End induction MRD > =0.01% was highly predictive of inferior outcome, though patients with 0.1–1% MRD who received intensive therapy had very low rates of early relapse and a much higher rate of late relapse. [Display omitted] 5 year EFS for end-induction MRD positive (>=0.01%) patients was 63±5% vs. 86±2% for MRD negative patients. However, patients who were MRD positive at end induction who became negative by end consolidation had improved 5y EFS of 79±9%(n=136) compared to 52±14% for those who remained MRD positive(n=52) (p=.0012). Both end induction MRD positive and negative patients benefitted from HD-MTX vs. C-MTX, though the effect was small and did not reach statistical significance for MRD positive patients. By contrast, end-induction MRD was highly predictive of outcome for patients receiving either HD-MTX or C-MTX.5 y EFS as a function of MRD status and IM regimen.End induction MRDCapizziHDMTXP value<.01%84 ± 3%88 ± 2%.04>.01%59 ± 6%67 ± 7%.12P value<.0001<.0001End induction MRD negative patients <10y receiving DEX had better outcome than those getting PRED (5 y EFS 92±3% vs. 87±4% P=.027) while MRD positive patients or those>10y showed no difference. However, DEX patients <10y if anything had a slightly higher rate of end induction MRD positivity than those given PRED (22% vs. 17%, p=.073). In multivariate analysis, end consolidation MRD was the most powerful prognostic factor for the small subset of patients in whom this was assessed. Excluding this, end induction MRD was the most significant variable; age, white blood cell count, day 15 marrow morphology and HD-MTX vs. C-MTX were also significant. We conclude that MRD remains the most powerful prognostic factor even in the context of improved therapy. Additionally, for those patients who were MRD positive at end induction, achieving MRD negative status by end consolidation improved outcome significantly. The higher frequency of MRD in younger patients receiving DEX calls into question the validity of using end induction MRD as a surrogate for outcome when testing novel interventions during induction therapy. Disclosures:Borowitz:BD Biosciences: Research Funding. Wood:BD Biosciences: Research Funding.

Significance of Minimal Residual Disease Monitored by Quantitative Assessment of WT1gene in Patients in First Remission of Acute Myeloid Leukemia Before Allogeneic Stem Cell Transplantation

Abstract 4485 PurposeThanks to the development of knowledge in the field of molecular biology, the great progress has been done in risk stratification of patients with acute myeloid leukemia (AML) at diagnosis, in recent years. Based on the recommendations of international expert groups there were identified the patients who may benefit from the allogeneic stem cell transplantation (allo-SCT) as a consolidation of first complete remission (CR). In the absence of an universal marker for minimal residual disease (MRD) measurements, there is still little information about the importance of MRD prior to allo-SCT. Our department has a very good experience with quantitative monitoring of WT1 gene expression as a marker of MRD during treatment of AML. The aim was to retrospectively evaluate the significance of MRD in patients indicated for allo-SCT in 1.CR. Patients and methodsOverall 35 patients (pts) in the first morphological CR were transplanted from April 2005 - July 2011. Median age was 46 years (range; 20–63), mens 14, women 21, three good risk, intermediate risk 23, high risk 7 (NA 3). A total of 19 pts achieved CR after second induction (salvage), 11 pts were in 1st iCR. Induction 3+7 was given to 31 pts (4x other), as consolidation has been used HIDAC in 28 pts (7x other). As the graft, peripheral blood stem cells were used in 27 pts, bone marrow in 8 pts. The donor was identical sibling in 15 pts (1x mismatched sibling), matched unrelated donor (MUD) in 10 pts and mismatched UD in 9 pts. Conditioning regimen was myeloablative in 29 pts, reduced-intensity in 6 pts. Median follow-up was 18 months (range; 2–56). The expression of WT1 gene was measured by real-time polymerase chain reaction in peripheral blood according to the European Leukemia Net recommendations. The WT1 expression was related to the expression of a reference gene and the results were calculated with a number of WT1 copies related to 104 copies of ABL gene. The upper limit of normal WT1 expression was set as 50 copies of WT1 to 104 copies of ABL. Before allo-SCT, 25 pts were WT1-negative, ten pts were WT1-positive. ResultsWhen comparing the two groups according the MRD status, there was not significant difference in terms of age, risk groups, first induction failure, number of iCR, induction or consolidation type. Also, type of graft, conditioning regimen, or HSCT-CI was not significantly different. The group of WT1-positive pts had more unrelated donors, more aGVHD and shorter follow-up. In terms of cGVHD, the groups were comparable.When comparing the overall survival (OS) and cumulative relapse incidence (RI) of the entire group in terms of: risk group, first induction failure, iCR, consolidations number and incidence of aGVHD, we found no significant difference. Pts with cGVHD had a better OS, lower RI with comparable non-relapse mortality (NRM).In contrast, the MRD status measured by WT1 gene expression appears as clearly significant factor. The outcome of WT1-positive pts is significantly worse in terms of OS (55% vs 83% at 3 years, p = 0.03), RI (50% vs 11% at 3 years, p = 0.008), and there is a trend toward higher NRM (23% vs 5% in 3 years, p = 0.08). ConclusionOur results show that MRD status measured by WT1 gene expression in patients with AML in 1.CR significantly affects their future prognosis. Opportunities to influence the unfavorable prognosis of MRD-positive patients may be more intensive pre-transplantation therapy or earlier immunomodulatory intervention after allo-SCT (pre-emptive DLI). The larger prospective studies are necessary to confirm this hypothesis.The study was supported by scientific project MZ 00023736 granted by the Ministry of Health, Czech Republic. Disclosures:No relevant conflicts of interest to declare.

小児白血病における微少残存腫瘍 (MRD) の臨床的意義

小児白血病における微少残存腫瘍 (MRD) の臨床的意義

Conventional Cytogenetics, Molecular Profiling, and Flow Cytometric Response Data Allow the Creation of a Two-Tiered Risk-Group System for Risk-Based Therapy Allocation In Childhood AML- a Report From the Children's Oncology Group

AbstractAbstract 761Conventional cytogenetics and morphologic response to induction chemotherapy have historically provided the tools for predicting outcome in patients with acute myeloid leukemia (AML). Several mutations are predictive of clinical outcome and have provided additional tools to help predict outcome in patients with AML without other risk features. Despite these recent advances, our ability to identify specific risk groups has been limited to a subset of patients, and nearly half of the patients with AML are regarded as having standard-risk (SR) disease. We inquired whether adding response by multidimensional flow cytometry (MDF) to data from conventional cytogenetics analysis and presence/absence of genomic alterations of FLT3 (FLT3-ITD), CEBPA, and NPM would provide a more robust risk-stratification system for risk-based therapy allocation. COG AML protocol AAML03P1 collected comprehensive cytogenetics characteristics, mutation profile (FLT3/ITD, CEBPA, and NPM mutation status), and MDF data on most of the 340 eligible patients enrolled on the study. Molecular and cytogenetic data were available for 275 of the 293 (94%) patients with responsive disease at the end of induction I. Disease-free survival (DFS) from the end of induction I was determined based on a combined molecular and cytogenetic risk profile. Risk status was defined based on the presence of t(8;21), inv(16), NPMc, and CEBPA mutations (favorable risk, FR) or the presence of monosomy 7, monosomy 5/del5q, and high allelic ratio FLT3-ITD (high risk, HR). On the basis of this allocation, 88 (32%) patients had FR AML, and 26 (10%) had HR AML. The remaining 161 (59%) patients without specific risk features were considered to have SR AML. DFS at 2 years from the end of induction I was 70%±12% for the FR cohort, 55% ±9% for the SR cohort, and 17%±20% for the HR cohort (p<0.001). The prevalence and prognostic significance of minimal residual disease (MRD) were assessed in the 103 patients with SR disease; 31 (30%) had evidence of MRD by MDF. DFS at 3 years from the end of induction I was significantly worse for those with MRD than for those without it (26%±21% vs. 67%±13%, p=0.01). Corresponding relapse risk in patients with or without MRD was 69%±21% and 30%±13%, respectively (p=0.011). We assessed the clinical impact of MRD in patients with HR or FR disease. Of the 18 patients with HR AML who had MRD data, 8 (44%) had MRD. DFS at 2 years for patients with HR disease with or without MRD was not significantly different (13%±23% vs. 36%±40%; p=0.127). Of the 73 patients with FR AML, MRD was detected in 12 (16%); MRD did not significantly influence DFS at 3 years from the end of induction I in those patients (45%±33% vs. 72%±17%, p=0.138). Thus, although the presence of MRD was significantly associated with worse outcome in patients with SR AML, similar significance could not be demonstrated in the FR or HR cohorts. Clinical outcomes of risk groups were reassessed after combining the MRD data with specific cytogenetic and molecular risk groups, i.e., patients with SR AML and MRD were added to the HR cohort, and those without MRD were added to the FR cohort. In the new risk-stratification system, 57 of 217 (26%) patients were in the HR cohort, and the remaining 160 (74%) patients were in the FR cohort. DFS at 3 years from induction I was 68%±9% for the FR cohort and 20%±16% (p<0.001) for the HR cohort. Cumulative incidence of relapse at 3 years from the end of induction I for those with FR or HR disease was 27%±9% and 71%±17%, respectively (p<0.001). Cytogenetics, molecular genotyping, and post-induction MDF analysis provide a robust means of stratifying all pediatric patients with AML into 2 risk groups with significantly different outcomes. This novel risk-allocation schema will be implemented in the upcoming COG Phase III AML trial. Disclosures:No relevant conflicts of interest to declare.

Significance of Minimal Residual Disease (MRD) by Multiparameter Flow Cytometry (MFC) In Adults with De Novo Acute Lymphoblastic Leukemia (ALL) After Therapy with the Modified Hyper-CVAD Regimen

AbstractAbstract 2145The hyper-CVAD regimen is an effective frontline program for de novo adult ALL [Kantarjian, JCO 18:547, 2000; Kantarjian, Cancer 101:2788, 2004]. Intensive cycles of hyper-CVAD (fractionated cyclophosphamide, vincristine [VCR], doxorubicin, dexamethasone) alternate with high dose methotrexate (MTX) and cytarabine every 21 days for 8 courses, followed by maintenance therapy with POMP (6-mercaptopurine, MTX, VCR, prednisone) interrupted with early and late intensifications. The regimen was modified in 1999 in order to improve on the results. Induction chemotherapy was administered in a laminar air flow room for pts aged 60 years or older owing to high induction mortality rate (17%). Rituximab 375 mg/m2 (days 1 & 11 of hyper-CVAD, days 1 & 8 of MTX-cytarabine for 8 total doses) was given if CD20 expression was > 20% owing to association with increased propensity for relapse [Thomas D, Blood 113:6330, 2009]. CNS prophylaxis alternated intrathecal MTX day 2 with cytarabine day 7 of the first 3 courses for low CNS risk and first 4 courses for high CNS risk (in the absence of CNS disease). The maintenance phase was extended from 24 to 30 mos with modifications of the early and late intensifications (hyper-CVAD followed by MTX-L-asparaginase mos 6 & 7 and 18 & 19) in order to reduce incidence of late relapses. Newly diagnosed or primary refractory (1 course only) pts with Philadelphia chromosome negative B-lymphoblastic leukemia (n=126) were treated with this modified hyper-CVAD regimen without anthracycline intensification (pts age 30 years or less have been allocated to treatment with the pediatric-inspired augmented Berlin-Frankfurt-Muenster regimen since 2006). Median age was 43 yrs (range, 15–83). CD20 expression was noted in 49%. Overall CR rate of the group was 93%; the rate of MRD negativity by 4- or 6-color MFC (sensitivity of 0.01%) at the time of CR in 95 evaluable pts was 72%. Overall, MRD positivity by MFC at the time of CR was associated with a higher relapse rate (52% versus 21%, p=.01) and lower 3-yr CR duration rates (45% versus 78%, p=.01). The CD20 positive pts (n=57) who were treated with rituximab had a higher rate of MRD negativity by MFC at CR than their CD20 negative counterparts (81% versus 58%, p=.02). MRD positivity by MFC after hyper-CVAD and rituximab was associated with a significantly lower 3-yr CR duration rate (24% versus 82%, p=.002), but survival rates were not statistically different (27% versus 70%) likely due in part to deaths in CR in the older subset of the MRD-negative group. In contrast, for the CD20 negative subset, presence of detectable MRD by MFC at the time of CR was not associated a with lower 3-yr CR duration rate (58% versus 63%). Dectectable MRD by MFC at the time of CR, despite subsequent eradication with consolidation chemotherapy in the majority of patients, predicts for increased risk of disease recurrence. Strategies to improve the MRD negativity rate at the time of CR (e.g., addition of monoclonal antibodies directed at other lymphoblast antigens such as CD22 for the CD20 negative subset and use of the newer anti-CD20 monoclonal antibodies for the CD20 positive subset) may further improve outcome after frontline therapy with the modified hyper-CVAD regimens. Disclosures:Thomas: Novartis: Honoraria; Bristol-Meyer-Squibb: Honoraria; Pfizer:; Amgen: Research Funding. Off Label Use: Imatinib for de novo Philadelphia positive ALL. Dasatinib for de novo Philadelphia positive ALL. Rituximab for CD20 positive ALL and Burkitt leukemia/lymphoma. Nelarabine for de novo T-lymphoblastic leukemia/lymphoma.

Minimal Residual Disease following Allogeneic Hematopoietic Stem Cell Transplantation

Minimal residual disease (MRD), both before and after transplantation, is a clinically important yet relatively poorly defined aspect of allogeneic hematopoietic stem cell transplantation (alloHSCT). The clinical relevance of MRD in the context of alloHSCT has been demonstrated by its association with the development of clinical relapse. However, with the possible exception of chronic myeloid leukemia (CML), the specific techniques, timing, frequency, and clinical utility, relative to improvement in patient outcomes, for monitoring MRD in the setting of alloHSCT has yet to be clearly defined. A concise overview of monitoring techniques for detecting MRD, as well as treatment strategies and biological and clinical research initiatives for MRD suggested by the National Cancer Institute First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation, is covered in this article.

Clinical significance of minimal residual disease in adult acute lymphoblastic leukemia

Monitoring minimal residual disease (MRD) in patients with acute lymphoblastic leukemia (ALL) is a useful way for assessing treatment response and relapse. We studied the value of MRD and showed a correlation with relapse for 34 adult patients with ALL. MRD was evaluated by real-time quantitative polymerase chain reaction (RQ-PCR) with probes derived from fusion chimeric genes (BCR/ABL) (n = 12) or PCR-based detection of clonal immunoglobulin and T cell receptor gene rearrangements (n = 16), or both (n = 6). We analyzed 27 of the 34 patients who could be examined for MRD on day 100 after induction therapy. The overall survival (OS) rate (45.0%) and relapse-free survival (RFS) rate (40.0%) at 2 years in complete remission (CR) patients with MRD level ≥ 10⁻³ (n = 12) were significantly lower than those in CR patients with MRD level <10(-3) (n = 15) (OS rate 79.0%, RFS rate 79.4%) (log-rank test, P = 0.017 and 0.0007). We also applied multicolor flow cytometry for comparison with MRD results analyzed by PCR methods. The comparison of results obtained in 27 follow-up samples showed consistency in 17 samples (63.0%) (P = 0.057). MRD analysis on day 100 is important for treatment decision in adult ALL.

Prognostic significance of minimal residual disease detected by a simplified flow cytometric assay during remission induction chemotherapy in children with acute lymphoblastic leukemia

PurposeOur study attempted to determine the prognostic significance of minimal residual disease (MRD) detected by a simplified flow cytometric assay during induction chemotherapy in children with B-cell acute lymphoblastic leukemia (B-ALL).MethodsA total of 98 patients were newly diagnosed with precursor B-ALL from June 2004 to December 2008 at the Asan Medical Center (Seoul, Korea). Of those, 37 were eligible for flow cytometric MRD study analysis on day 14 of their induction treatment. The flow cytometric MRD assay was based on the expression intensity of CD19/CD10/CD34 or aberrant expression of myeloid antigens by bone marrow nucleated cells.ResultsThirty-five patients (94.6%) had CD19-positive leukemic cells that also expressed CD10 and/or CD34, and 18 (48.6%) had leukemic cells with aberrant expression of myeloid antigens. Seven patients with ≥1% leukemic cells on day 14 had a significantly lower relapse-free survival (RFS) compared to the 30 patients with lower levels (42.9% [18.7%] vs. 92.0% [5.4%], P=0.004). Stratification into 3 MRD groups (≥1%, 0.1-1%, and <0.1%) also showed a statistically significant difference in RFS (42.9% [18.7%] vs. 86.9% [8.7%] vs. 100%, P=0.013). However, the MRD status had no significant influence on overall survival. Multivariate analysis demonstrated that the MRD level on day 14 was an independent prognostic factor with borderline significance.ConclusionAn MRD assay using simplified flow cytometry during induction chemotherapy may help to identify patients with B-ALL who have an excellent outcome and patients who are at higher risk for relapse.

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

Significance of Minimal Residual Disease in Patients with Chronic Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation.

Abstract 3269Poster Board III-1▪▪This icon denotes an abstract that is clinically relevant.Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a potentially curative treatment for patients (pts) with chronic myeloid leukemia (CML). AlloHSCT is associated with long-term disease-free survival in 40% to 80% pts transplanted in early chronic phase of disease. The probability of relapse for pts transplanted in first chronic phase is 10% to 20% at 5 years, and is even higher (30% – 60%) for pts who received transplant in advanced phases of CML. The significance of minimal residual disease (MRD) in this clinical setting is uncertain. We enrolled 63 consecutive pts with CML who had received an alloHSCT between 1995 and 2007 and had BCR-ABL transcript quantity measured by RQ-PCR method on at least 2 occasions during follow-up in the period starting 6 months after alloHSCT. The reverse transcription was preformed using SuperScriptIII and random hexamers. Quantification of BCR-ABL was performed by RQ-PCR assay according to ‘Europe Against Cancer' protocol. BCR-ABL expression was normalized with endogenous control ABL gene and expressed as a ratio BCR-ABL/ABL. According to the amount of BCR-ABL transcript detected in blood or bone marrow after alloHSCT pts were allocated into 3 categories, including pts with no-detectable or stable very low-level of BCR-ABL transcripts (ratio BCR-ABL/ABL below 0.005%), pts with fluctuating-low level of BCR-ABL transcripts (0.005 – 0.01%) and pts with high-level of BCR-ABL transcripts (0.01 – 0.1%). We didn't find any relationships between different BCR-ABL levels after alloHSCT and clinical parameters at the time of CML diagnosis or transplantation, including Sokal, Hasford and Gratwohl scores. Median time from alloHSCT to molecular relapse (MR) was 38 months (range, 8.5 – 88.5 months). The 3-year progression rate into cytogenetic or hematological relapse of CML since MR was 70%. This progression occurred at a median time of 1.4 months (range, 0 – 3.2 months). We found strong correlation between the levels of BCR-ABL transcripts after alloHSCT and a risk of relapse. The incidence of MR was 0%, 26%, 71% for the low-level, fluctuating-low level and high-level of BCR-ABL transcript (p<.0001), respectively. Similarly the risk of cytogenetic and hematological relapse was 0%, 21%, 43% for these pts (p=.001), respectively. Five-year leukemia-free survival was 100%, 83.9% and 66.7% for the pts with low-level, fluctuating-low level and high-level BCR-ABL transcript (p=.003), respectively. There was no apparent relationship between the level of BCR-ABL transcript and overall survival. We conclude that pts with fluctuating-low and/or high levels of BCR-ABL transcripts are at higher risk of disease progression. Sequential RQ-PCR monitoring coupled with pre-emptive therapy can provide a valid strategy to reduce rates of relapse and development of a more individualized approach to management of pts with CML in major molecular response after alloHSCT. Disclosures:Warzocha:BMS: Consultancy, Honoraria; Celgene: Consultancy; Roche: Honoraria; Pfizer: Honoraria; Amgen: Honoraria.

Clinical significance of minimal residual disease at day 15 and at the end of therapy in childhood acute lymphoblastic leukaemia

Detection of minimal residual disease (MRD) after induction and consolidation therapy is highly predictive of outcome for childhood acute lymphoblastic leukaemia (ALL) and is used to identify patients at high risk of relapse in several current clinical trials. To evaluate the prognostic significance of MRD at other treatment phases, MRD was measured by real-time quantitative polymerase chain reaction on a selected group of 108 patients enrolled on the Australian and New Zealand Children's Cancer Study Group Study VII including 36 patients with a bone marrow or central nervous system relapse and 72 matched patients in first remission. MRD was prognostic of outcome at all five treatment phases tested: at day 15 (MRD > or = 5 x 10(-2), log rank P < 0.0001), day 35 (> or =1 x 10(-2), P = 0.0001), 4 months (> or =5 x 10(-4), P < 0.0001), 12 months (MRD > or = 1 x 10(-4), P = 0.006) and 24 months (MRD > or = 1 x 10(-4), P < 0.0001). Day 15 was the best early MRD time-point to differentiate between patients with high, intermediate and low risk of relapse. MRD testing at 12 and particularly at 24 months, detected molecular relapses in some patients up to 6 months before clinical relapse. This raised the question of whether a strategy of late monitoring and salvage therapy will improve outcome.

Prognostic significance of minimal residual disease in infants with acute lymphoblastic leukemia treated within the Interfant-99 protocol

Acute lymphoblastic leukemia (ALL) in infants younger than 1 year is a rare but relatively homogeneous disease ( approximately 80% MLL gene rearranged, approximately 70% CD10-negative) when compared with childhood and adult ALL. Several studies in children and adults with ALL have shown that minimal residual disease (MRD) status is a strong and independent prognostic factor. We therefore evaluated the prognostic significance of MRD in infant ALL. Ninety-nine infant patients treated according to the Interfant-99 protocol were included in this study. MRD was analyzed by real-time quantitative PCR analysis of rearranged immunoglobulin genes, T-cell receptor genes and MLL genes at various time points (TP) during therapy. Higher MRD levels at the end of induction (TP2) and consolidation (TP3) were significantly associated with lower disease-free survival. Combined MRD information at TP2 and TP3 allowed recognition of three patients groups that significantly differed in outcome. All MRD-high-risk patients (MRD levels > or =10(-4) at TP3; 26% of patients) relapsed. MRD-low-risk patients (MRD level <10(-4) at both TP2 and TP3) constituted 44% of patients and showed a relapse-rate of only 13%, whereas remaining patients (MRD-medium-risk patients; 30% of patients) had a relapse rate of 31%. Comparison between the current Interfant-06 stratification at diagnosis and the here presented MRD-based stratification showed that both stratifications recognized different subgroups of patients. These data indicate that MRD diagnostics has added value for recognition of risk groups in infant ALL and that MRD diagnostics can be used for treatment intervention in infant ALL as well.

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

Quantitative MRD Assessments Predict Progression Free Survival in CLL Patients Treated with Fludarabine and Cyclophosphamide with or without Rituximab – a Prospective Analysis in 471 Patients from the Randomized GCLLSG CLL8 Trial

Data from randomized clinical trials investigating the clinical significance of minimal residual disease (MRD) quantification during and immediately after standard therapy in CLL are still lacking. We therefore related 4-color MRD flow results to progression free survival (PFS) and achievement of complete clinical remission (CCR) in patients (pts) from the GCLLSG CLL8 trial who were randomized to receive 6 cycles of fludarabine and cyclophosphamide (FC) or FC plus Rituximab (FCR). MRD was assessed before therapy, after 3 cycles (interim staging, IS), 1 month (mo) after therapy (initial response assessment, IRA) and 2 mos after IRA (final restaging, FR). 1402 samples from 471 patients who had received at least 3 cycles of therapy were included in the analysis (1162 peripheral blood, PB, 240 bone marrow, BM samples). While initial disease levels were identical between the treatment arms, median PB MRD levels were significantly lower within the FCR arm at IS, IRA, and FR (IS 5.8×10−3 vs. 5.8×1−4, IRA 3.6×1−4 vs. 0, FR 4.4×1−4 vs. 0, all p < 0.0001). Likewise, median BM infiltration was higher after FC than after FCR at IRA (1.6×10−3 vs. 2.1×10−4, p = 0.05) and at FR (8.1×10−4 vs. 1.2×10−4, p<0.0001). The proportion of PB samples with MRD below 10−4 was significantly higher in the FCR arm than in the FC arm (33.6% vs. 6.4% at IS, 67.6% vs. 36.6% at IRA, 66.4% vs. 34.2% at FR, all p < 0.0001). BM samples with MRD levels below 10−4 at FR accounted for 47.6% and 27.3% of samples from the FCR and FC arms, respectively (p=0.005). MRD results were classified into 5 cohorts (<10−4, >=10−4 to < 10−3, >= 10−3 to <10−2, >= 10−2 to < 10−1, and >10−1) in order to assess the prognostic significance of MRD for PFS. Significant differences in median PFS were obtained when PB MRD levels at IS were grouped into <10−2 (70.2% of pts, PFS 44 mos), >= 10−2 to < 10−1 (19.7% of pts, PFS 27 mos) and >10−1 (10.1 % of pts, PFS 11 mos). The PFS of all pts who experienced an MRD reduction below 10−2 was similar, regardless of the exact level. Considering PB MRD levels at FR, clear cut differences in median PFS were observed between pts demonstrating levels < 10−4 (49.6 % of pts, PFS not reached), >= 10−4 and < 10−2 (36.8% of pts, 34 mos) and >= 10−2 (13.6% of pts, 15 mos). Further subdivisions within those 3 cohorts resulted in very similar Kaplan-Meier estimates. BM MRD levels at FR were best classified into two groups, comprising pts with MRD levels of at least 10−2 and below 10−2, respectively. Pts from the former group (11.9 % of pts) experienced a median PFS of 15 mos, compared to a median PFS of 43 mos in the latter group (88.1 %). When MRD levels and treatment regimens were analyzed simultaneously for prognostic significance, only MRD levels were identified as prognostic parameter for PFS using Cox regression in this model. This was tested for PB at IS as well as for PB and for BM at FR. Pts who received FCR achieved up to the FR significantly lower MRD levels and were more often MRD negative. However, once low-level MRD was achieved it had the same prognostic significance in both treatment arms. MRD levels at IS were also associated with the achievement of CCR. Thus, only 14.7% of patients with an MRD level of at least 10−2 achieved a CCR after therapy compared to 49.4% of pts with an MRD level below that threshold (p<0.0001). In summary higher MRD levels were generally associated with shorter PFS whereas lower MRD levels predict longer PFS, regardless of sampling time point, sample material and treatment regimen. Identical MRD levels are associated with similar PFS in both treatment arms. We show that the addition of Rituximab to FC leads to lower median MRD levels compared to FC alone, resulting in longer overall PFS in the FCR group.

Prospective monitoring of BCR‐ABL1 transcript levels in patients with Philadelphia chromosome‐positive acute lymphoblastic leukaemia undergoing imatinib‐combined chemotherapy

The clinical significance of minimal residual disease (MRD) is uncertain in patients with Philadelphia chromosome-positive acute lymphoblastic leukaemia (Ph+ ALL) treated with imatinib-combined chemotherapy. Here we report the results of prospective MRD monitoring in 100 adult patients. Three hundred and sixty-seven follow-up bone marrow samples, collected at predefined time points during a uniform treatment protocol, were analysed for BCR-ABL1 transcripts by quantitative reverse transcription polymerase chain reaction. Ninety-seven patients (97%) achieved complete remission (CR), and the relapse-free survival (RFS) rate was 46% at 3 years. Negative MRD at the end of induction therapy was not associated with longer RFS or a lower relapse rate (P = 0.800 and P = 0.964 respectively). Twenty-nine patients showed MRD elevation during haematological CR. Of these, 10 of the 16 who had undergone allogeneic haematopoietic stem cell transplantation (HSCT) in first CR were alive without relapse at a median of 2.9 years after transplantation, whereas 12 of the 13 who had not undergone allogeneic HSCT experienced a relapse. These results demonstrate that, in Ph+ ALL patients treated with imatinib-combined chemotherapy, rapid molecular response is not associated with a favourable prognosis, and that a single observation of elevated MRD is predictive of subsequent relapse, but allogeneic HSCT can override its adverse effect.

Clinical significance of minimal residual disease in patients with t(8;21) acute myeloid leukemia in Japan

To examine the prognostic significance of minimal residual disease (MRD) in t(8;21) acute myeloid leukemia (AML), 96 bone marrow samples from 26 Japanese patients in complete remission (CR) were analyzed regarding the RUNX1/MTG8 transcript using real-time reverse transcriptase polymerase chain reaction assay. All patients were treated with intensive chemotherapy. The median copy number of the RUNX1/MTG8 transcript, measured after each treatment course decreased over time. However, an increase in the MRD level was documented in three patients after the second consolidation, and all of them subsequently relapsed. The relapse-free survival (RFS) did not differ between the patients whose MRD levels were below or above 1,000 copies/microg after the first consolidation, with respective 2-year rates of 62 and 86% (P = 0.21). With respect to the MRD level after induction therapy, our data also failed to show any favorable effect of a lower MRD on RFS. Although these findings need to be confirmed with a larger number of patients, our data indicate that the MRD level at a given time during the early course in CR does not predict the outcome in Japanese patients.

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia and its relationship to other prognostic factors: a Children's Oncology Group study

AbstractMinimal residual disease (MRD) is an important predictor of relapse in acute lymphoblastic leukemia (ALL), but its relationship to other prognostic variables has not been fully assessed. The Children’s Oncology Group studied the prognostic impact of MRD measured by flow cytometry in the peripheral blood at day 8, and in end-induction (day 29) and end-consolidation marrows in 2143 children with precursor B-cell ALL (B-ALL). The presence of MRD in day-8 blood and day-29 marrow MRD was associated with shorter event-free survival (EFS) in all risk groups; even patients with 0.01% to 0.1% day-29 MRD had poor outcome compared with patients negative for MRD patients (59% ± 5% vs 88% ± 1% 5-year EFS). Presence of good prognostic markers TEL-AML1 or trisomies of chromosomes 4 and 10 still provided additional prognostic information, but not in National Cancer Insitute high-risk (NCI HR) patients who were MRD+. The few patients with detectable MRD at end of consolidation fared especially poorly, with only a 43% plus or minus 7% 5-year EFS. Day-29 marrow MRD was the most important prognostic variable in multi-variate analysis. The 12% of patients with all favorable risk factors, including NCI risk group, genetics, and absence of days 8 and 29 MRD, had a 97% plus or minus 1% 5-year EFS with nonintensive therapy. These studies are registered at www.clinicaltrials.gov as NCT00005585, NCT00005596, and NCT00005603.

Prognostic Significance of Minimal Residual Disease (MRD) in Childhood B-Precursor ALL and Its Relation to Other Risk Factors. A Children's Oncology Group (COG) Study.

Early response to therapy, including assessment of MRD is a powerful prognostic factor in childhood ALL. However, there are many other known prognostic factors, and the precise relationship among these and MRD has been incompletely explored. In COG protocol P9900, patients were assigned to one of 3 risk-directed therapies based on NCI risk group, as well as TEL-AML1 translocations (TEL) and simultaneous trisomies of chromosomes 4 and 10 (DT). Infants and Ph+ patients were excluded. Good risk patients (9904) comprised NCI SR patients with either TEL or DT without CNS disease. Poor risk patients (9906) included a subset of NCI HR patients with particularly unfavorable risk factors based largely on age and white count, while 9905 had both NCI SR and HR patients not eligible for 9904 or 9906, including NCI HR patients with TEL or DT. MRD was satisfactorily measured with at least .01% sensitivity by 4-color flow cytometry in the marrow at end of induction (D29) or in blood at Day 8 (D8). D29 MRD was associated with poor outcome in all studies, and in both HR and SR patients on 9905 as shown:Study4 y EFS ± SE (n)p valueMRD <.01%MRD >.01%9904Overall94±1%(668)75±6%(105)<.0001TEL-AML194±2%(367)68±12%(38)<.0001DT95±1%(316)80±7%(69)<.00019905NCI-Standard Risk89±2%(462)63±6%(119)<.00019905NCI-High Risk83±4%(292)49±9%(73)<.0001990674±6%(156)39±8%(84)<.0001The proportion of D29 MRD positive DT(17.9%) patients was higher than that of TEL patients (9.4%) but MRD was also prognostic when each group was considered separately; similar findings were seen in HR TEL and DT patients. TEL or DT was associated with a significantly better prognosis in both HR and SR patients who were MRD negative, but were not favorable factors in MRD positive patients. D8 blood MRD was also prognostic in all studies, with higher MRD levels generally associated with poorer outcome. Patients who were both D29 and D8 MRD negative had a good outcome overall (93% 4 y EFS); combining all favorable risk factors, including TEL, DT, NCI risk group, D8 and D29 MRD identified a group of patients (about 13% of B-precursor ALL patients) with 98± 1% 4 y EFS. In multivariate analysis, D29 MRD was the most important prognostic factor. NCI Risk group, DT and D8 blood were also significant, but TEL and day 8 morphologic assessment of marrow were not. We conclude that MRD is a major prognostic factor in childhood ALL even accounting for other risk factors. The prognostic significance of TEL and DT depends on MRD status. The combination of good risk clinical and genetic factors, and absence of MRD in both D8 blood and D29 marrow identifies a group of patients with outstanding outcome on limited therapy.

The detection and significance of minimal residual disease in acute and chronic leukemia

Minimal residual disease (MRD) can be detected in many patients with leukemia who have achieved complete remission as defined by conventional pathology examination. The detection of MRD, be it by flow cytometry or by polymerase chain reaction assays, has now been found to be associated with subsequent relapses in most leukemia subtypes, either following chemotherapy or following hematopoietic stem cell transplantation. These assays are now increasingly used in clinical trial design to optimize therapy and provide a novel way to assess treatment efficacy.