scholarly journals Deep Sequencing Approach for Minimal Residual Disease Detection in Acute Lymphoblastic Leukemia

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1388-1388
Author(s):  
Malek Faham ◽  
Jianbiao Zheng ◽  
Martin Moorhead ◽  
Victoria Carlton ◽  
Patricia Lee Stow ◽  
...  

Abstract Abstract 1388 Background: The clinical management of patients with acute lymphoblastic leukemia (ALL) relies on accurate prediction of relapse hazard to determine the intensity of therapy and avoid over- or under-treatment.1 The measurement of minimal residual disease (MRD) during therapy has now emerged as the most important predictor of outcome in ALL.2 We developed the LymphoSIGHT platform, a high-throughput sequencing method, which universally amplifies antigen-receptor gene segments and can identify all leukemia-specific sequences at diagnosis, allowing monitoring of disease progression and clonal evolution during therapy. In this study, we determined the sensitivity and specificity of this method, delineated the extent of clonal evolution present at diagnosis, and compared its capacity to measure MRD to that of flow cytometry and allele-specific oligonucleotide PCR (ASO-PCR) in follow-up samples from >100 patients with ALL. Methods: Using the sequencing assay, we analyzed diagnostic bone marrow samples from 100 ALL patients for clonal rearrangements of immunoglobulin (IgH@) and T cell receptor (TRB@, TRD@, TRG@) genes, as well as the extent of clonal evolution present at diagnosis. We assessed the capacity of the sequencing assay to detect MRD using diagnostic samples from 12 ALL patients carrying 13 leukemic IgH clonal rearrangements. Serial dilutions were prepared in normal peripheral blood mononucleated cells, at a range between <1 in 1 million to >1 in 1,000 cells. We also assessed MRD in follow-up samples from 106 ALL patients and analyzed concordance between MRD results obtained by the sequencing assay, flow cytometry and ASO-PCR. Results: In diagnostic bone marrow samples, we detected the presence of a high-frequency clonal rearrangement of at least one receptor (“calibrating receptor”) in all the 100 ALL samples; 94 samples had at least 2 calibrating receptors at diagnosis, with 51 having 3 or more. We also detected a variable degree of clonal evolution: the number of evolved clones in each sample ranged from 0 to 6933, with 39 (37%) samples having 1–50 evolved clones and 17 (16%) >50 (Figure 1). In experiments with mixtures of normal and leukemic cells, the sequencing assay unequivocally and accurately detected leukemic signatures in all dilutions up to a concentration of at least one leukemic cell in 1 million leukocytes. In direct comparisons with established MRD assays performed on follow-up samples from patients with B-ALL, sequencing detected MRD in all 28 samples positive by flow cytometry, and in 35 of the 36 positive by ASO-PCR; it also revealed MRD in 10 and 3 additional samples that were negative by flow cytometry and ASO-PCR, respectively (Figure 2). Conclusions: The sequencing assay is precise, quantitative, and can detect MRD at levels below 1 in 1 million leukocytes (0.0001%), i.e., represents sensitivity 1–2 orders of magnitude higher than standard flow cytometric and ASO-PCR methods. Our assay also allows monitoring of all leukemic rearrangements regardless of their prevalence at diagnosis, which abrogates the risk of false-negative MRD results due to clonal evolution. Finally, the sequencing assay utilizes a set of universal primers and does not require development of patient-specific reagents. These data, together with the results of our comparison with standard MRD assays in clinical samples, strongly support the use of the sequencing assay as a next-generation MRD test for ALL. Disclosures: Faham: Sequenta: Employment, Equity Ownership, Research Funding. Zheng:Sequenta: Employment, Equity Ownership, Research Funding. Moorhead:Sequenta: Employment, Equity Ownership, Research Funding. Carlton:Sequenta: Employment, Equity Ownership, Research Funding.

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4984-4984
Author(s):  
Norman J. Lacayo ◽  
Li Weng ◽  
Charles Gawad ◽  
Malek Faham ◽  
Gary V Dahl

Abstract Background Detection of minimal residual disease (MRD) in pediatric acute lymphoblastic leukemia (ALL) is a strong predictor of outcome. In addition, MRD testing prior to stem cell transplant for ALL can inform on the risk of relapse. The ClonoSIGHT test uses deep sequencing of immunoglobulin and T-cell receptors to identify and monitor MRD. In retrospective cohorts, we have previously shown this technology is highly correlated with flow cytometry and PCR-based MRD methods, but has even greater sensitivity than both technologies (Faham et al, Blood 2012; Gawad et al, Blood 2012).  Here we report on four clinical cases where we used the ClonoSIGHT assay to prospectively monitor MRD, in both the medullary and extramedullary compartments, to demonstrate the feasibility of this technology for MRD monitoring of children with relapsed ALL. Methods Universal primer sets were used to amplify rearranged variable (V), diversity (D), and joining (J) gene segments from the immunoglobulin heavy and kappa chain (IGH and IGK), as well as T-cell receptor beta, delta and gamma.  The assay was performed on genomic DNA isolated from cells from the bone marrow, cerebrospinal fluid, or testes.  The test was first done at the time of relapse to identify the malignant clonotype, which was monitored at subsequent time points. The patients were ineligible for clinical trials and concurrently underwent MRD testing using flow cytometry. The sequencing assays were performed to show feasibility of the approach. Results  Patient one was a 14 y/o ALL relapse patient who was not in morphologic remission after standard re-induction therapy. The malignant clonotype was identified on a bone marrow aspirate from relapse; follow-up MRD tests were done using both flow cytometry and deep sequencing five times throughout salvage therapy with 5-aza-2'-deoxycytidine, suberoylanilide hydroxamic acid and high dose cytarabine over 75 days; the last two MRD data points showed 0.6% and 6% by ClonoSIGHT MRD and 0.4% and 1.3% by flow cytometry MRD. Morphologic remission with count recovery was used as the criteria to direct this patient to SCT. Patient two was a 9 y/o with ALL, for whom MRD was used to test for relapsed disease in multiple tissues.  This patient experienced three isolated testicular relapses (M1 marrow and no CNS involvement) at the time of each relapse. The ClonoSIGHT assay was used on tissue from a testicular biopsy to identify the malignant clone(s).  Testing of the bone marrow and cerebrospinal fluid did not detect the malignant clones in those sites. This patient underwent therapeutic orchiectomy and 4-week systemic re-induction resulting in a fourth complete remission and now is under evaluation for consolidation therapy with a SCT. A third patient was an 8 y/o with a combined bone marrow and testicular ALL relapse, who was in morphologic remission in the marrow after re-induction therapy and testicular radiotherapy. Prior to undergoing SCT the patient had negative MRD by flow cytometry but had 0.008% MRD using the ClonoSIGHT MRD assay.  The fourth patient was a 15-yo with ALL relapse at 9 years from first remission, treated with a four-drug re-induction and Berlin-Frankfurt-Münster based consolidation and maintenance therapy.  This patient was MRD negative by both flow cytometry and ClonoSIGHT MRD at end of re-induction as well as end of consolidation and remains in remission. Conclusions We have shown the feasibility of using sequencing-based tests for monitoring MRD in children with relapsed ALL in medullary (bone marrow) and extramedullary compartments (testes and CSF).  Further studies are needed to establish the prognostic value of MRD detected by the ClonoSIGHT assay in both medullary and extramedullary sites that are below the limit of detection of PCR and flow cytometry. These sequencing-based tests may provide a useful tool to develop risk stratification schemas for drug development in relapsed childhood ALL. Disclosures: Weng: Sequenta, Inc.: Employment, Equity Ownership. Faham:Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1551-1551 ◽  
Author(s):  
Michael A. Pulsipher ◽  
Xia Han ◽  
Máire Quigley ◽  
Gabor Kari ◽  
Susana Rives ◽  
...  

Abstract Introduction Detection of minimal residual disease (MRD) is an important predictor of patient outcome following treatment of B-cell acute lymphoblastic leukemia (B-ALL). We assessed concordance between two MRD assays, with different assay sensitivities, to determine which MRD detection method could support early relapse detection. Immunoglobulin next generation sequencing (Ig NGS) and flow cytometry (FC) were tested in samples from two clinical trials ELIANA (NCT02435849) and ENSIGN (NCT02228096) for pediatric relapsed and refractory B-ALL patients treated with tisagenlecleucel. We also assessed whether using blood with Ig NGS would be comparable to BM testing with FC. Finally we analyzed whether clonal evolution, as detected by Ig NGS, occurred during of the course of therapy for both CD19+ and CD19- relapse patients. Methods In this analysis, bone marrow and peripheral blood specimens at screening (pre-tisagenlecleucel infusion), post-infusion and relapse were tested. Ig NGS was performed in 300 samples from 88 patients. 237 samples from 83 patients also had FC MRD results available. MRD was measured on fresh blood and bone marrow using a 3-tube FC assay (CD10, CD19, CD13, CD20, CD22, CD33, CD34, CD38, CD45, CD58, CD123). The FC MRD assay has a lower limit of sensitivity of 0.01% of white blood cells. Ig NGS detection of MRD was performed using the Adaptive Biotechnology's NGS MRD assay. MRD quantitative values, along with the qualitative MRD calls at each assay sensitivity level (10-4, 10-5 and 10-6) were reported. At baseline, 85 out of 88 samples had informative clones. Results and Conclusions To examine the comparability of flow cytometry and Ig NGS methods in assessing MRD, baseline and post-treatment samples were tested. Baseline samples, which had a high disease burden, showed 100% MRD concordance between both assays. However, post-treatment, where the leukemic burden was dramatically reduced, Ig NGS detected a greater number of MRD positive samples compared to FC, at each sensitivity level tested (10-4, 10-5 and 10-6). At the highest sensitivity level of 10-6, Ig NGS was able to detect 18% more MRD positive post-treatment samples. Importantly, Ig NGS was able to detect MRD positivity 1-4 months ahead of clinical relapse in a small number of relapsed patients, whether relapse was CD19+ or CD19-. This may provide an important window of opportunity for pre-emptive treatment while a patients' tumor burden is still low. In B-ALL, it has previously been described that MRD levels can be one to three logs lower in blood compared to bone marrow (VanDongen JJ et al. Blood 2015). Our results support these findings whereby MRD burden in bone marrow was higher than in blood using both FC and Ig NGS. We next set out to determine if the increased sensitivity afforded by the Ig NGS assay could provide a level of MRD detection in the blood comparable to FC in the bone marrow. In patients with matching data available, Ig NGS was able to detect more MRD positive blood samples than FC MRD positive bone marrow samples. This suggests that monitoring of MRD using Ig NGS in the blood holds the potential to be used as a surrogate for FC MRD in bone marrow. The relationship between MRD and prognosis was examined. Patients who were MRD negative by both Ig NGS and FC at the end of first month post-infusion had better progression-free survival and overall survival compared to those with detectable MRD. Tumor clonality will be further analyzed to understand sub-clone composition at baseline and clonal evolution following tisagenlecleucel treatment. Taken together, these results highlight the importance of using a highly sensitive assay, such as Ig NGS, when monitoring for MRD. MRD detection by Ig NGS holds the potential to identify early response/relapse in patients, which could provide a window of opportunity for additional intervention before morphological relapse. Ongoing studies with larger patient groups will provide further information on the applicability of Ig NGS MRD detection and its association with long-term outcome in tisagenlecleucel-treated pediatric r/r B-ALL patients. Disclosures Pulsipher: Novartis: Consultancy, Honoraria, Speakers Bureau; CSL Behring: Consultancy; Amgen: Honoraria; Adaptive Biotech: Consultancy, Research Funding. Han:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Quigley:Novartis Pharmaceuticals Corporation: Employment. Kari:Adaptimmune LLC: Other: previous employment within 2 years; Novartis Pharmaceuticals Corporation: Employment. Rives:Shire: Consultancy, Other: Symposia, advisory boards ; Amgen: Consultancy, Other: advisory board ; Novartis Pharmaceuticals Corporation: Consultancy, Other: Symposia, advisory boards ; Jazz Pharma: Consultancy, Other: Symposia, advisory boards . Laetsch:Bayer: Consultancy; Eli Lilly: Consultancy; Pfizer: Equity Ownership; Novartis Pharmaceuticals Corporation: Consultancy; Loxo Oncology: Consultancy. Myers:Novartis Pharmaceuticals Corporation: Consultancy, Honoraria, Research Funding, Speakers Bureau. Qayed:Novartis: Consultancy. Stefanski:Novartis Pharmaceuticals Corporation: Consultancy, Honoraria, Speakers Bureau. Baruchel:Shire: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; Servier: Consultancy; Roche: Consultancy; Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Travel, accommodations or expenses; Celgene: Consultancy. Bader:Cellgene: Consultancy; Riemser: Research Funding; Medac: Patents & Royalties, Research Funding; Neovii: Research Funding; Novartis: Consultancy, Speakers Bureau. Yi:Novartis Pharmaceuticals Corporation: Employment. Kalfoglou:Novartis Pharmaceuticals Corporation: Employment. Robins:Adaptive Biotechnologies: Consultancy, Employment, Equity Ownership, Patents & Royalties. Yusko:Adaptive Biotechnologies: Employment, Equity Ownership. Görgün:Novartis Pharmaceuticals Corporation: Employment. Bleickardt:Novartis Pharmaceuticals Corporation: Employment. Wong:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Grupp:Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy; Adaptimmune: Consultancy; University of Pennsylvania: Patents & Royalties.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2612-2612 ◽  
Author(s):  
Daniel DeAngelo ◽  
Wendy Stock ◽  
Stephen Petersdorf ◽  
Shaw-Ling Wang ◽  
Angela Volkert ◽  
...  

Abstract Abstract 2612 Background: Inotuzumab ozogamicin (INO) is a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic antitumor agent. CD22 is expressed on a majority of B-cell acute lymphoblastic leukemia (ALL). An initial study suggested INO efficacy and tolerability in ALL (Lancet Oncol 2012;13:403-11). Objectives: The current phase 1, multicenter, dose-escalation study was performed to optimize the INO dose and schedule (weekly dosing) based on safety, efficacy, and pharmacokinetic data in CD22+ relapsed or refractory ALL. The safety and efficacy of INO at the recommended dose and schedule will subsequently be further evaluated in a 12-patient (pt) expanded cohort. Methods: Eligible pts were aged ≥18 y with CD22+ ALL (defined as ≥20% blasts CD22+ by flow cytometry) refractory to initial induction or in relapse (≥first relapse), with no evidence of central nervous system disease. INO was administered in 28-d cycles (see Table), with a maximum of 6 cycles. The final dose was to be determined based on both toxicity (ie, rate of dose-limiting toxicities [DLT] at each dose level) and evidence of efficacy using the EffTox V2.10 software (Biometrics 2004;60:684–693). Adverse event (AE) severity was assessed per CTCAE V3 with DLTs defined as any of the following INO-related events during Cycle 1: grade ≥4 non-hematologic toxicity; prolonged myelosuppression (absolute neutrophil count [ANC] <500/μL or platelets <25,000/μL in bone marrow) with no evidence of leukemia persisting >45 d from last dose; grade 3 non-hematologic toxicity persisting >7 d from the last dose; grade ≥3 elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), or bilirubin persisting >7 d; or any toxicity resulting in permanent INO discontinuation. Weekly teleconferences with investigators were used to assess toxicity. Complete response (CR) was defined as <5% bone marrow blasts with absence of peripheral blasts, ANC ≥1,000/μL, platelets >100,000/μL, and no extramedullary disease; incomplete CR (CRi) was similar but permitted ANC <1,000/μL and/or platelets ≤100,000/μL. Results: We report preliminary data for 13 pts (see Table), with a median duration of follow-up of 147 d (range, 30–188 d). Median age was 56 y (range, 23–65 y), and 69% of pts were male. Five (39%) pts were in salvage 1, 2 (15%) were in salvage 2, and 4 (31%) were in salvage ≥3. Two pts had prior allogeneic stem cell transplant. Three (23%) pts were Ph+ and 7 (54%) pts had circulating blasts at baseline; median baseline WBC was 2.01×103/mm3 (range, 0.5–29.11×103/mm3). The single DLT observed to date was transient grade 4 elevated lipase occurring at INO dose level 3. The most frequent (≥10% of pts) treatment-related AEs were thrombocytopenia (31%, all grade 3/4), neutropenia (15%), and elevated ALT (15%). Treatment-related elevated AST and alkaline phosphatase were each reported for 8% of pts. Reported dose delays were due to thrombocytopenia (n = 3), neutropenia (n = 2), elevated LFT (n = 2), bacteremia, increased blood creatinine, periorbital cellulitis, and QTc prolongation (n = 1 each). Fourteen serious AEs were reported for 9 pts, including 2 cases each of febrile neutropenia and septic shock. Responses were observed across all INO doses explored to date (see Table). The preliminary response rate was 82% (9/11 evaluable pts), including 36% of pts with a CR and 45% with a CRi. Median time to response was 43 d (range, 28–56 d). Six of 9 (67%) pts who achieved CR/CRi also achieved minimal residual disease (<1 blast out of 104 mononuclear cells by flow cytometry). Seven pts discontinued treatment, including 1 each due to disease progression and an AE (acute renal failure, not treatment related), and 5 pts who proceeded to transplant. Four deaths were reported, including 1 due to disease progression and 3 due to sepsis occurring within 30 d after stem cell transplantation. Conclusions: INO had a safety profile consistent with prior reports, characterized by hematologic, gastrointestinal, and hepatic events and infection. The remarkable response rate of 82% for single-agent INO in this relapsed/refractory population warrants further exploration in CD22+ ALL. Updated results will be presented at the meeting. Disclosures: Stock: Tau for work done through the CALGB/ALLIANCE: Research Funding. Wang:Pfizer Inc: Employment, Equity Ownership. Volkert:Pfizer Inc: Employment, Equity Ownership. Vandendries:Pfizer Inc: Employment, Equity Ownership. Advani:Pfizer Inc: Consultancy, Honoraria, Research Funding.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 228-228
Author(s):  
Torsten Haferlach ◽  
Manja Meggendorfer ◽  
Susanne Schnittger ◽  
Annette Fasan ◽  
Wolfgang Kern ◽  
...  

Abstract Introduction: The cure rate in AML is dependent on patient´s (pts) age and performance, cytogenetics, early blast clearance and sustainable first complete remission. Investigation of minimal residual disease (MRD) is possible by multiparameter flow cytometry and molecular techniques. Recent findings have further depicted a broad spectrum of molecular markers in AML in 99% of pts (TCGA, NEJM, 2013). This broadens the portfolio of targets for MRD assessment and will hopefully help to better individualize treatment strategies. We here focused - as a paradigm - on the three hallmarks for molecular MRD studies in AML. Aims: To better define the clinical impact and to suggest strategies for MRD monitoring in AML with PML-RARA, CBFB-MYH11, and RUNX1-RUNX1T1. Patients and Methods: Between 2005 und 2015 we at diagnosis investigated 321 PML-RARA, 134 CBFB-MYH11, and 145 RUNX1-RUNX1T1 AML pts. Individual follow-up time points during their course of disease were studied in 2657, 1047, and 890 samples, respectively. Thus, the combined number of investigated samples is 4,594. Molecular techniques applied comprised quantitative real-time PCR and nested PCR. Median age in PML-RARA was 52 years (yrs) (2-86 yrs), in CBFB-MYH11 53 yrs (21-81 yrs), and in RUNX1-RUNX1T1 52 yrs (10-83 yrs). Median time between 2 investigations was 3.0 months (mo) in PML-RARA, 2.1 mo in CBFB-MYH11, and 2.8 mo in RUNX1-RUNX1T1 pts (range for all 0.1-40.4 mo), respectively. All pts were treated with standard protocols according to genotype and age. Allogeneic bone marrow or stem cell transplantation was performed in 85 pts (14%). Results: 294/321 pts (92%) with PML-RARA achieved complete molecular remission (CMR) after a median of 2.9 mo (range: 0.8-9.7 mo). In contrast, in CBFB-MYH11 CMR was reached in 89/134 pts (66%) after a median of 7.4 mo (range: 1.6-16.8 mo), and in RUNX1-RUNX1T1 CMR was reached in 75/145 pts (51%) after a median of 4.7 mo (range: 1.0-11.5 mo). Of note, some of the CBFB-MYH11 pts never reached CMR, always showing low level signals. 95% (278/294) of PML-RARA pts that achieved CMR stayed in first CMR and did not relapse within a median follow-up of 32.6 mo (range: 1.2-134.5 mo). 5% (16/294) relapsed at a median interval after CMR of 8.1 mo. However, a second CMR was reached in 12/16 pts after relapse. Five of these 12 pts suffered from second relapses, whereof 4 pts achieved a third CMR. Third relapses occurred in 2/4 pts. 69/89 (78%) of pts with CBFB-MYH11 stayed in first CMR and never relapsed during a median follow-up of 10.4 mo (range: 1.6-47.1 mo). 20/89 relapsed after 4.0 mo of CMR, whereof 11 achieved second CMR. 3/11 relapsed again. 63/75 (84%) of pts with RUNX1-RUNX1T1 stayed in first CMR and never relapsed during a median follow-up of 10.1 mo (range: 1.0-65.8 mo). However, 12/75 relapsed after a median time of CMR of 5.3 mo. 4/12 achieved another CMR. In 85 patients (10 PML-RARA, 42 CBFB-MYH11, and 33 RUNX1-RUNX1T1) allogeneic bone marrow or stem cell transplantation (Tx) was performed, and 72/85 (85%) were rescued by Tx. However, two patients each with PML-RARA and RUNX1-RUNX1T1 relapsed, respectively, and 9 in CBFB-MYH11 positive AML after Tx. Patients did not experience first relapse later than 50.3 mo in CMR in PML-RARA, later than 30.7 mo in CBFB-MYH11, and later than 35.7 mo in RUNX1-RUNX1T1. Additionally, keeping periods between two MRD samplings at a maximum of 3 mo allowed the detection of nearly all cases of first relapse due to the molecular hint. Addressing the sensitivity levels of the assays applied to bone marrow (BM) versus peripheral blood (pB) samples showed a 1.4 fold higher sensitivity for BM samples (median copies of reference gene, 13,204 vs 9,240). Due to the comparable sensitivities pB can be investigated until a first hint of relapse, followed by BM sampling for confirmation. Conclusions: 1) MRD by molecular techniques reliably defines pts risks in AML with PML-RARA, CBFB-MYH11, and RUNX1-RUNX1T1, respectively. 2) Clinical decisions are reliable within screening intervals of 3 mo using pB. 3) Relapses in first CMR are not detected later than 50.3 mo in PML-RARA, 30.7 mo in CBFB-MYH11, and 35.7 mo in RUNX1-RUNX1T1 AML, respectively. 4) Pts after relapse can be rescued by transplantation in the majority of cases. 5) As the availability of other molecular markers in AML has dramatically increased, more individualized treatment strategies based on specific MRD monitoring are achievable in nearly every patient in the near future. Disclosures Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Fasan:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1976-1976
Author(s):  
Andy Rawstron ◽  
Claudia Fazi ◽  
Neus Villamor ◽  
Julio Delgado ◽  
Remi Letestu ◽  
...  

Abstract BACKGROUND. The detection of minimal residual disease (MRD) at the level of 0.01%/10-4 or above is a strong independent predictor of reduced progression-free (PFS) and overall survival (OS) in patients with CLL treated with chemoimmunotherapy. Although newer agents such as B-cell receptor pathway inhibitors can result in prolonged survival without achieving complete response, there remains a important role for MRD analysis in assessing therapeutic strategies aimed at disease eradication and cure. This is particularly important in front-line trials for fit patients which now require at least five years of follow-up if PFS is used as an endpoint. The feasibility of using MRD as a surrogate or intermediate endpoint for accelerated approval of new treatments is under review by regulatory agencies but further prospective validation is required. At the same time technology is rapidly evolving and high-throughput sequencing (HTS) technologies now detect MRD at the 0.0001%/10-6 level. It is therefore important to determine the most effective approaches for quantifying MRD that are compatible with previous studies but sufficiently sensitive for current treatments. AIMS. This collaborative project had two objectives. First, to identify the simplest and most flexible flow cytometry panel capable of detecting MRD at the 0.01%/10-4 or lower, that is compatible with published data and independent of instrument/reagent manufacturer. Second, to compare the flow cytometry approach with HTS analysis using the ClonoSEQ assay (Adaptive Biotechnologies, Seattle, WA). METHODS AND RESULTS. A core panel of antibodies for MRD detection was identified by testing an 8-marker combination in 52 samples (27 post-treatment and 25 dilution study) and re-analysing data with serial exclusion of single markers to determine redundancy. A 1-tube core panel of CD19, CD20, CD5, CD43, CD79b, and CD81 was identified and validated against the previously published 2-tube 6-marker and 4-tube 4-marker ERIC panels in 76 samples (19 post-treatment and 57 dilution study). The results showed good concordance (for log-transformed data above the LoQ, linearity=0.977, Pearson correlation co-efficient=0.983, average difference=0.026 log, 95% limit of agreement 0.20log) and a limit of detection of 0.001%/10-5 for the 1-tube core panel. Inter-operator variation was similar to CML MRD monitoring with both experienced operators, or inexperienced cytometrists after ~1 hour of specific education, achieving a 95% limit of agreement less than 0.3log in samples with MRD levels ranging from 0.0001 – 100%. The flow cytometry approach was compared with the ClonoSEQ HTS assay in 109 samples (21 dilution study and 88 post-treatment samples, complete data currently available on 13/88). The assay was applicable to the vast majority CLL patients, often with two clonal markers. There was 94% concordance at the 0.01% (10-4) threshold (15 samples with ≥0.01% CLL by both methods, 14 samples with <0.01% by both methods, 1 sample with 0.03% CLL by HTS and <0.003% CLL by flow cytometry, and 1 sample with 0.005% CLL by HTS and 0.012% by flow cytometry. HTS detected CLL IGH sequences in 22% (7/31) samples with no detectable CLL cells by flow cytometry (i.e. CLL level 0.0001-0.001%, 3/13 patient samples and 4/18 dilution samples). HTS demonstrated a relatively high variability in quantification, as seen in previous studies, but with a clear superiority in the limit of detection and good linearity (linearity=0.905, Pearson correlation co-efficient=0.870, average difference=0.078 log, 95% limit of agreement 1.5 log). CONCLUSIONS. The 1-tube 6-marker flow cytometry core panel is compatible with published studies, manufacturer-independent and flexible, providing directly quantitative results to 0.001%/10-5 without requiring a pre-treatment sample. HTS requires further work to standardise the quantitative analysis and prospective validation but the ClonoSEQ assay is applicable to >95% of CLL patients, does not require viable cells and is extremely sensitive, detecting residual disease in a significant proportion of cases with <0.01% CLL. The results indicate that flow cytometry and HTS are complementary technologies with a combined approach offering the most reliable way of quantifying CLL at the 0.01%/10-4 threshold while allowing higher sensitivity in clinical trials aimed at disease eradication. Disclosures Rawstron: Roche: Honoraria; Biogen Idec: Consultancy; Gilead: Consultancy, Honoraria; Abbvie: Honoraria; BD Biosciences: Intrasure reagent Patents & Royalties; Celgene: Honoraria; GSK: Honoraria. Williamson:Adaptive Biotechnologies: Employment, Equity Ownership. Sanders:Adaptive Biotechnologies: Employment, Equity Ownership. Robins:Adaptive Biotechnologies: Consultancy, Equity Ownership, Patents & Royalties. Hallek:Celgene: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GSK: Honoraria; Gilead: Honoraria. Hillmen:Roche: Honoraria, Research Funding; GSK: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Gilead: Honoraria, Research Funding.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1378-1378
Author(s):  
Roger Belizaire ◽  
Olga Pozdnyakova ◽  
Daniel J. DeAngelo ◽  
Betty Li ◽  
Karry Charest ◽  
...  

Abstract Flow cytometry for detection of minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL) has been widely used in pediatric patients to quantify therapeutic response and to assess the risk of relapse. Flow cytometry for MRD provides roughly the same level of sensitivity (0.01%) as molecular methods but at lower cost and with faster turnaround time. MRD assessment in ALL currently requires an evaluation of 20 or more parameters divided among multiple tubes. In part due to the assessment complexity, the use of flow cytometry for MRD detection in adult ALL patients has been relatively limited. We developed a 6-color, single-tube, flow cytometry assay to detect MRD in bone marrow (BM) aspirate specimens from adult ALL patients. The 73 patients included 52 patients with B-ALL (71%), 19 patients with T-ALL (26%) and 2 patients with T/myeloid leukemia (3%) and were treated with one of several standard chemotherapeutic regimens or targeted therapies. Patients were tested for MRD by flow cytometry after induction or re-induction therapy and serially thereafter. The 6-marker MRD panel was customized for each patient based on the 18-20-marker diagnostic immunophenotype. Sixty-three percent of B-ALL patients (n=33) had lymphoblasts with an aberrant immunophenotype; expression of a myeloid marker (e.g., CD13, CD15 or CD33) was the most common aberrancy. The remaining 37% of B-ALL patients (n=19) had disease with a hematogone immunophenotype, which comprised surface expression of CD10, CD19, CD20, CD34, CD38 and CD45; in the majority of these cases, leukemic cells were distinguishable from normal hematogones based on the intensity of surface marker expression. Forty-seven percent of T-ALL patients (n=9) had an aberrant immunophenotype, most often characterized by CD33 expression. One-hundred forty-six consecutive specimens analyzed for MRD by flow cytometry were classified as positive (23%), negative (72%) or uncertain (5%). Of the 34 samples classified as positive, 14 (41%) showed morphologic (i.e., BM aspirate or biopsy) evidence of disease; nineteen (65%) samples did not show morphologic evidence of disease and 1 sample did not have a concurrent morphologic assessment. Of the 105 samples classified as negative by flow cytometry, 103 (98%) were also negative by morphology and 1 sample did not have a concurrent morphologic assessment. One sample that was negative by flow cytometry had morphologic evidence of disease in the biopsy (10-20% blasts) but not the aspirate, suggesting that aspirate sampling artifact was responsible for the discrepancy. None of the 7 samples classified as uncertain by flow cytometry had morphologic evidence of disease; five out of 7 uncertain classifications were in B-ALL patients with hematogone immunophenotypes. Overall, MRD flow cytometry showed 86% concordance with the results of morphologic assessment. We evaluated outcomes in all patients with negative morphologic results and any positive MRD flow cytometry result(s). Of the 73 patients in this study, 61 had morphology-negative results that were either MRD-negative (n=45) or MRD-positive (n=16). Patients in this group were at various points of treatment post-induction or re-induction. Four out of 45 patients (9%) with MRD-negative results relapsed during a median follow-up period of 22 months, and 8 out of 16 patients (50%) with an MRD-positive result relapsed during a median follow-up period of 15 months (odds ratio for relapse 10.3, 95% confidence interval 2.5-42.4, P=0.001). In addition, relapse-related and overall mortality (Figure 1) were higher in patients with MRD-positive results (P=0.0023 and P=0.0016, respectively, by the log-rank test). In summary, we present a simplified, single-tube, flow cytometry assay that can be used to detect MRD in adult ALL at relatively low cost with rapid turnaround time; our approach was applicable to cases with either hematogone or aberrant immunophenotype, yielding a definitive result in 95% of cases. Notably, the presence of MRD was associated with relapse and mortality, suggesting that our method of MRD assessment could be used to guide treatment of adult ALL. Further analysis of the correlations between MRD results, clinical management and patient outcomes is ongoing. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3774-3774
Author(s):  
Sofie J Alm ◽  
Charlotte Engvall ◽  
Julia Asp ◽  
Lars Palmqvist ◽  
Jonas Abrahamsson ◽  
...  

Abstract The translocation t(12;21)(p13;q22) resulting in the fusion gene ETV6-RUNX1, is the most frequent gene fusion in childhood precursor B lymphoblastic leukemia (pre-B ALL), affecting about one in four children with pre-B ALL. In the NOPHO ALL-2008 treatment protocol, treatment assignment in pre-B ALL is based on clinical parameters, genetic aberrations, and results from analysis of minimal residual disease (MRD) at day 29 and 79 during treatment (where MRD >0.1% leads to upgrading of treatment). For pre-B ALL, in this protocol MRD analysis is performed using flow cytometry as the method of choice. In this study, we also analyzed MRD in t(12;21)(p13;q22) cases with quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for the fusion transcript ETV6-RUNX1 in parallel with routine MRD analysis with flow cytometry, to determine if qRT-PCR of the ETV6-RUNX1 fusion transcript would be a reliable alternative to FACS. Bone marrow samples were collected at diagnosis and at day 15, 29 and 79 during treatment from 31 children treated according to the NOPHO ALL-2000 (n = 3) and NOPHO ALL-2008 (n = 28) protocols in Gothenburg, Sweden, between 2006 and 2013. Samples were analyzed in parallel with qRT-PCR for ETV6-RUNX1 fusion transcript and with FACS. For qRT-PCR, mRNA was isolated, cDNA synthesized, and qRT-PCR performed with GUSB as reference gene. MRD-qRT-PCR was defined as the ETV6-RUNX1/GUSB ratio at the follow-up time point (day 15/29/79) divided with the ETV6-RUNX1/GUSB ratio at diagnosis (%). MRD analysis with FACS was performed, after lysis of erythrocytes, using antibodies against CD10, CD19, CD20, CD22, CD34, CD38, CD45, CD58, CD66c, CD123, and terminal deoxynucleotidyl transferase, and when applicable also CD13 and CD33. Results of MRD-FACS were expressed as % of all cells. In total, 83 samples were analyzed with both methods in parallel; 31 from day 15 in treatment, 28 from day 29, and 24 from day 79. Overall, MRD-qRT-PCR showed good correlation with MRD-FACS. In total, 31 samples were positive with qRT-PCR and 24 with FACS, with concordant results (positive with both methods or negative with both methods) in 89% of samples, when the limit of decision (positive/negative MRD) was set to 0.1%. The concordance was especially high at the treatment stratifying time points, i.e. day 29 and 79; 89% and 100%, respectively. No samples at these time points were positive with FACS but negative with qRT-PCR. During the follow-up period (6-81 months), one patient relapsed (with negative MRD with both methods at stratifying time points), and two succumbed from therapy-related causes. Our results show that there is a significant relationship between the results of MRD analysis using FACS and MRD analysis using qRT-PCR of ETV6-RUNX1 fusion transcript. The high concordance between the methods indicates that negative MRD using qRT-PCR is as reliable as negative MRD using FACS, and that qRT-PCR could therefore be an alternative to FACS in cases where FACS is not achievable. In comparison to quantitative PCR of TCR/Ig gene rearrangements, which is the current backup MRD method for cases with pre-B ALL in NOPHO ALL-2008, qRT-PCR of ETV6-RUNX1 is much less time and labor consuming, making it appealing in a clinical laboratory setting. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4908-4908 ◽  
Author(s):  
Giordana Pastori ◽  
Fabio Guolo ◽  
Daniela Guardo ◽  
Paola Minetto ◽  
Marino Clavio ◽  
...  

Abstract BACKGROUND AND AIMS The prognosis of Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) patients has improved since the introduction of tyrosine kinase inhibitors (TKI). The inclusion of TKIs in standard ALL protocols allows a great increase in complete molecular responses, but at the price of non negligible toxicities and high rates of toxic deaths. On the other and TKI monotherapy as induction treatment allows to rapidly achieve complete hematologic remission (CR) but only a minority of patients achieve a complete molecular response with high risk of relapse. On the other hand, In the last years we tested a combination of Fludarabine, Cytarabine, Daunoxome (FLAD) with or without TKIs (mainly Dasatinib) as salvage regimen in relapsed-refractory ALL, with acceptable toxicity and good efficacy. We decided to apply the same schedule in newly diagnosed Ph+ ALL as consolidation treatment after a two months TKI (Dasatinib) monotherapy induction on a minimal residual disease condition. MATERIALS AND METHODS FLAD regimen consisted with a three-days administration of Fludarabine 30 mg/sqm followed four hours later by Cytarabine 2000 mg/sqm and Daunoxome 100 mg/sqm. TKI were suspended during chemotherapy administration and were re-administrated starting from day 5. G-CSF was given to all patients from day 4 to complete hematological recovery. FLAD was administrated for up to two cycles; all patients with available donor proceeded to allogeneic bone marrow transplantation (allo-BMT) after FLAD. Minimal residual disease (MRD) was evaluated in all patients after each FLAD either by RQ-PCR for VDJ rearrangements, multicolor flow cytometry (MFC) and RQ-PCR for BCR/Abl. Ten Ph+ ALL have been treated with FLAD + TKIs from January 2008 to December 2014: six patients received FLAD as salvage regimen, two of them in post allo-BMT setting, whereas four patients were treated frontline, after hematological CR was obtained with Dasatinib + steroids induction. All frontline patients proceeded to allo-BMT after two FLAD. Median age for frontline patients was 50 years (range 29-58), median follow-up was 20 months. RESULTS As salvage regimen, 5/6 patients achieved hematological CR after FLAD, with three patients achieving also MFC MRD negativity and clearance of VDJ and BCR/Abl transcript. All patients who did not receive subsequent BMT relapsed, whereas of the two transplanted patients one is still in CR after a follow-up of 38 months. In the frontline setting, all patients received 70 days induction of Dasatinib + Steroids and achieved CR with complete hematological recovery. BCR/Abl transcript could be detected in all patients on BM samples on day 33 and on day 70 (Fig. 1), two patientshad MFC MRD positivity both on day 33 and on day 70, whereas two patients achieved MFC MRD negativity on day 33. FLAD was very well tolerated, with negligible non hematological toxicity, with a median duration of ANC <500 and PLT <20000 of 7 and 9 days, respectively, slightly higher in the second course. Median time between the beginning of first and second course was 35 days, whereas median time from second course to allo-BM was 44 days. Two patients achieved BCR/Abl negativity after first FLAD. All patients achieved molecular complete response after the second course (Fig. 1). No patient experienced relapse, whereas one patient died in CR on day +289 after allo-BMT due to myocardial viral infection. CONCLUSIONS FLAD has a very good efficacy in adult Ph+ ALL, with an acceptable toxicity profile. Deep responses have been observed in relapsed patients, and all newly diagnosed patients who received FLAD as consolidation regimen had achieved molecular CR before allo-BMT. Achieving complete hematological response with Dasatinib + steroids allowed us to safely administer two FLAD courses. Figure 1. BCR/abl on bone marrow samples at different timepoints for each of the four patients receiving FLAD as consolidation therapy Figure 1. BCR/abl on bone marrow samples at different timepoints for each of the four patients receiving FLAD as consolidation therapy Disclosures Off Label Use: Use of liposomal daunorubicin in the treatment of ALL.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1710-1710
Author(s):  
Torsten Haferlach ◽  
Claudia Haferlach ◽  
Wenke Worseg ◽  
Karolína Perglerová ◽  
Wolfgang Kern ◽  
...  

Abstract Introduction: Investigation of minimal residual disease (MRD) using NPM1 as a target has been proven to be of importance in AML. Guidelines for best schedules and implication on clinical use need to be defined. Aims: To better define the clinical impact and to suggest strategies for MRD monitoring in AML with NPM1 mutation. Patients and Methods: Between 2005 and 2015 we investigated 428 AML patients (pts) with NPM1 mutation at diagnosis and at a minimum of 2 follow-up time points. All pts had to achieve at least once a complete molecular remission (CMR) to be considered for this study. Sensitivity for MRD detection was at least 1:10,000. The median age of the cohort was 57 years (range: 18-85 yrs) and comprised of 198 males and 230 females. 3,039 samples (median number of samples per pts: 7, range: 2-35) were studied during course of disease. Molecular techniques applied included gene scan, sequencing and quantitative real-time PCR at diagnosis and quantitative real-time PCR during follow-up. Median time between 2 investigations was 2.8 months (mo; range: 0.3-71.0 mo). All pts were treated with standard protocols according to genotype and age. Allogeneic bone marrow or stem cell transplantation was performed in 136 pts (31.8%). Results: NPM1 type A mutation was the most frequent mutation type (317/428, 74.1%), followed by type B and D (36/428, 8.4% and 23/428, 5.4%), respectively. 25 other NPM1 types occurred at frequencies between 0.2 and 3.7%, in total demonstrating the expected distribution of NPM1 mutation types in an adult AML cohort. Subgroups of these pts were analyzed for FLT3-ITD (n=421) and mutations in DNMT3A (n=236). 122/421 (29%) pts showed a FLT3-ITD. In 96/236 (41%) DNMT3A was mutated. Further in 33/235 (14%) both genes were mutated. 103/235 (44%) screened for all three genes had a sole NPM1 mutation. All sole NPM1 mutated study pts achieved the CMR after a median of 4.1 mo (range: 1.0-8.6 mo). The presence of an additional DNMT3A mutation (CMR after a median of 4.4 mo, range 1.0-8.7) or a FLT3-ITD (CMR after a median of 2.7 mo, range 1.0-8.7) or both mutations (CMR after a median of 4.1 mo, range 1.1-7.9 mo) had no influence on time to achieve CMR. After achievement of CMR an increase of NPM1 ratio was detected in 185/428 (43%) pts. The median time to loss of CMR was 5.1 mo (range: 0.4-88 mo). In more detail, 42/185 of these patients also had FLT3-ITD, 53/109 had DNMT3A mutations and 13/109 had mutations in both genes. Patients with a DNMT3A mutation showed more often loss of CMR (40/60, 67%), while FLT3-ITD and FLT3-ITD/DNMT3A mutated patients showed no significant influence on loss of CMR ratio (46% and 48%, respectively) maybe due to number of cases. In 152/185 molecular relapses further follow up samples after loss of CMR were available. The median time between detected loss of CMR and the next follow-up sample was 2.0 mo. Due to treatment intervention 46/152 patients achieved a second CMR and 27/152 a decrease in NPM1 ratio. However, in 79/152 a further increase leading to clinical relapse was observed. The increase after loss of CMR was in median 13-fold between first and second sample after CMR was lost. Importantly, keeping periods between two MRD samplings at an interval of 3 mo allowed the detection of nearly all cases of first relapse at the molecular level. Addressing the sensitivity levels of the assays applied to bone marrow (BM) versus peripheral blood (pB) samples showed a 1.6 fold higher sensitivity for BM samples (median copies of reference gene, 14,628 vs 9,363). Due to the comparable sensitivities pB can be investigated until a first increase on the molecular level is detectable, followed by BM sampling for confirmation 4 weeks later. Conclusions: 1) NPM1 has proven to be a good marker for MRD monitoring in AML. 2) Time to CMR is short with a median of 4.1 mo. 3) An increase of NPM1 in all cases is followed by relapse after a median of 5.1 mo, if no treatment intervention has been initiated before. 4) Time intervals for MRD should be no longer than 3 mo, pB can be used. 5) Transplantation should already be planned after first molecular increase is detected. Disclosures Haferlach: MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Worseg:MLL Munich Leukemia Laboratory: Employment. Perglerová:MLL2 s.r.o: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Meggendorfer:MLL Munich Leukemia Laboratory: Employment.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3416-3416 ◽  
Author(s):  
Andy C Rawstron ◽  
Walter Gregory ◽  
Ruth M de Tute ◽  
Faith E Davies ◽  
Susan E Bell ◽  
...  

Abstract Minimal residual disease (MRD), as assessed by flow cytometry is a powerful predictor of outcome in multiple myeloma (MM). We and others have previously demonstrated that such analyses are informative in patients treated with autologous stem cell transplant (ASCT) and non-transplant regimens. It predicts outcome in patients in conventional CR and is applicable to patients with standard and adverse risk cytogenetics. As a consequence MRD assessment is under consideration as a surrogate endpoint for clinical trials. This is urgently needed in MM as >5yrs follow-up is typically required to demonstrate survival differences in trials of upfront therapy. If surrogate end points are to be used in clinical trials it is essential that a reproducible effect is demonstrable using multivariate models. Previous studies have confirmed the effect of MRD on PFS but a consistent effect on OS has been not been definitively shown. This may in part be due to the availability of effective salvage therapy but it is also possible that the traditional threshold of 10-4 for analysis and the categorization of patients as MRD-postive or negative is suboptimal. Flow cytometry does provide a quantitative assessment of residual tumour over a large range and the degree of tumour depletion may be more informative than a positive-negative analysis. 397 patients from the MRC Myeloma IX trial were included in this analysis. Patients were randomly assigned to CTD (cyclophosphamide, thalidomide, and dexamethasone) or CVAD (cyclophosphamide, vincristine, doxorubicin, and dexamethasone) induction for 4-6 cycles followed by standard high-dose melphalan (HDM) ASCT. BM aspirates were obtained at day 100 for MRD analysis. 500,000 cells were evaluated with six-colour antibody combinations including CD138/CD38/CD45/CD19 with CD56/CD27 in all cases and CD81/CD117 in additional cases as required. PFS and OS data analysis was landmarked from the date of the MRD assesment. Of the 397 patients with MRD data available at day 100 after ASCT, 247/397 (62.2%) achieved <0.01% MRD. The level of residual disease varied across four logs in MRD-positive patients (0.01-<0.1% in 49/397, 0.1-<1% in 72/397, 1-<10% in 26/397 and ≥10% in 3/397). The PFS and OS for individuals with ≥1% residual disease was comparable to individuals with a PR/MR/SD confirming that MRD assessment is most relevant in CR. The level of MRD correlated with outcome. The median PFS for patients with ≥10% MRD at day 100 after ASCT was 0.8 years, with 1-<10% MRD was 1.7 years, with 0.1-<1% MRD was 1.9 years, with 0.01-<0.1% MRD was 2.7 years and for patients with <0.01% MRD was 3.1 years (P<0.001). The median OS for these groups was 1 yr, 4 yrs, 5.9 yrs, 6.8 yrs and for patients with <0.01% MRD not reached with >7.5 yrs median follow-up (P<0.001, see figure). A Cox proportional hazards model was used to further evaluate factors influencing outcome. B2M and MRD were log-transformed and along with age were considered as continuous variables. ISS, haemoglobin (<115g/l), platelets (<150x10^9/l) and cytogenetics were used as stratification factors. Cytogenetic groups were classified as unfavourable for patients with gain(1q), del(1p32), t(4;14), t(14;20), t(14;16), and del(17p), or favourable for hyperdiploidy, t(11;14) and t(6;14), or unknown/inevaluable. MRD assessment (χ2 11.8, P=0.0006) and cytogenetics (χ2 35.5, P=<0.0001) were the only factors that retained significance in this multivariate model. Conventional categorical response, ISS and B2M were not predictive of OS (p=0.99, 0.16 and 0.56 respectively). We would conclude that MRD quantitation is more informative than a positive or negative categorization with a 10-4 threshold and independently predicts outcome. In this analysis we were able to demonstrate an approximate 1 year survival benefit per log tumour depletion. A lower cutpoint for predicting improved outcome was not reached and more sensitive assays will likely improve outcome prediction further. This data strongly supports the role of MRD assessment as a surrogate endpoint in clinical trials. Figure 1 Figure 1. Disclosures Rawstron: Celgene: Consultancy; BD Biosciences: Consultancy, Intrasure Patents & Royalties. Gregory:Celgene: Consultancy. Davies:Celgene: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Novartis: Consultancy. Cook:Celgene: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria. Jackson:Celgene: Honoraria; Janssen-Cilag: Honoraria. Morgan:Celgene: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Owen:Celgene: Consultancy, Honoraria, Research Funding.


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