MRD-positive Group Research Articles

Measurable Residual Disease Assessment and Allogeneic Transplantation as Consolidation Therapy in Adult Acute Lymphoblastic Leukemia in Colombia

IntroductionDetectable minimal residual disease (MRD) after therapy for acute lymphoblastic leukemia (ALL) is the strongest predictor of hematologic relapse. The objective of the study was to assess disease-free survival (DFS) and overall survival (OS) of patients with ALL according with MRD status at the end of induction therapy in a Colombian population. Patients and MethodsWe assessed a retrospective cohort to compare DFS and OS in adults with de novo ALL according to MRD status at the end of induction chemotherapy, and the type of postinduction consolidation strategy used. ResultsA total of 165 adults with ALL were included in the MRD part of the study, 73 patients in the MRD-negative group and 92 in the MRD-positive group. Median DFS for the MRD-positive group was 11 months (95% confidence interval, 11.7-22.2) and was not reached for the MRD-negative group (P < .001). At 3 years, DFS was 18% and 55%, respectively (P < .001). The median OS for MRD-positive patients was 16 months (95% confidence interval, 8.8-23.15) and was not reached in the MRD-negative group. At 3 years, OS was 26% and 51% for the former and latter group, respectively. Among subjects who did not receive a transplant, median DFS was 21 months for MRD-negative patients and 9 months for MRD-positive patients (P < .001). The median DFS was not reached in either group, whereas 3-year DFS was 64% for MRD-negative and 70% for MRD-positive patients who underwent transplantation in first remission (P = .861). ConclusionMRD status at the end of induction is an independent prognostic factor for DFS and OS in adult ALL. Allogeneic transplantation in first remission could overcome the adverse prognostic impact of MRD.

Measurable residual disease after the first consolidation predicts the outcomes of patients with acute promyelocytic leukemia treated with all-trans retinoic acid and chemotherapy.

We stratified patients with newly diagnosed acute promyelocytic leukemia (APL) according to a white blood cell (WBC) count of ≥ 3 × 109/L (high risk) or < 3 × 109/L (low risk) before administering risk-adapted chemotherapy in combination with all-trans retinoic acid (ATRA). In total, 27 low-risk and 23 high-risk patients were assigned to receive induction and three courses of consolidation with ATRA and anthracycline, followed by 2-year maintenance regimen. High-risk group additionally received cytarabine during 1st consolidation and another one-shot idarubicin treatment during 3rd consolidation. We prospectively monitored measurable residual disease (MRD) after induction and each consolidation. In the low-risk and high-risk groups, 5-year disease-free survival (DFS) rates were 86.5% and 81.2% (p = 0.862), and 5-year overall survival rates were 100% and 84.8% (p = 0.062), respectively. In the MRD-negative and MRD-positive groups, 5-year DFS rates were 91.7% and 78.4% (p = 0.402) and 84.7% and 60.0% (p = 0.102) after induction and 1st consolidation, respectively. Relapse rates were 8.3% and 13.3% (p = 0.570) and 9.0% and 40.0% (p = 0.076) after induction and 1st consolidation, respectively. Achieving MRD-negativity after 1st consolidation, rather than after induction, was a potential predictor of relapse and DFS in patients with APL treated with ATRA + chemotherapy.

Assessment of minimal residual disease using multiparametric flow cytometry in patients with AL amyloidosis

AbstractDespite achieving a hematologic complete response after treatment, many patients with AL amyloidosis do not attain recovery of organ function and/or experience hematologic relapse. A persistent plasma cell clone producing amyloidogenic light chains at levels below the detection threshold of traditional serologic methods is hypothesized to impede organ response in some patients. Assessment of minimal residual disease (MRD) may therefore have clinical importance as a more stringent treatment response tool for patients in a hematologic complete response. We used 2-tube, 10-color combination multiparametric flow cytometry to assess for MRD at a minimum sensitivity of 1 in 105 nucleated cells. Of 65 patients in hematologic complete response, 36 (55%) were found to have a residual clonal plasma cell population in the bone marrow. Comparing the MRD-negative and MRD-positive groups, renal response was observed in 88% vs 64% (P = .06), cardiac response in 75% vs 59% (P = .45), and any organ response in 90% vs 75% (P = .20) of patients. Depth of organ response as measured by the percent decrease in 24-hour proteinuria and brain natriuretic peptide was 96% vs 91% (P = .16) and 55% vs 46% (P = .66), respectively. These data suggest a possible correlation between MRD negativity and higher probability of organ response after treatment in AL amyloidosis. Future prospective studies with a larger cohort are needed to determine the clinical relevance of these improvements. This trial was registered at www.clinicaltrials.gov as #NCT00898235.

Impact of minimal residual disease status in patients with relapsed/refractory acute lymphoblastic leukemia treated with inotuzumab ozogamicin in the phase III INO-VATE trial

Minimal residual disease (MRD) negativity is a key prognostic indicator of outcome in acute lymphocytic leukemia. In the INO-VATE trial (clinicaltrials.gov identifier: NCT01564784), patients with relapsed/refractory acute lymphocytic leukemia who received inotuzumab versus standard chemotherapy achieved greater remission and MRD-negativity rates as well as improved overall survival: hazard ratio 0.75, one-sided P = 0.0105. The current analysis assessed the prognostic value of MRD negativity at the end of inotuzumab treatment. All patients who received inotuzumab (n = 164) were included. Among patients with complete remission/complete remission with incomplete hematologic response (CR/CRi; n = 121), MRD-negative status (by multiparametric flow cytometry) was defined as <1 × 10–4 blasts/nucleated cells. MRD negativity was achieved in 76 patients at the end of treatment. Compared with MRD-positive, MRD-negative status with CR/CRi was associated with significantly improved overall survival and progression-free survival, respectively: hazard ratio (97.5% confidence interval; one-sided P-value) 0.512 (97.5% CI [0.313–0.835]; P = 0.0009) and 0.423 (97.5% CI [0.256–0.699]; P < 0.0001). Median overall survival was 14.1 versus 7.2 months, in the MRD-negative versus MRD-positive groups. Patients in first salvage who achieved MRD negativity at the end of treatment experienced significantly improved survival versus that seen in MRD-positive patients, particularly for those patients who proceeded to stem cell transplant. Among patients with relapsed/refractory acute lymphocytic leukemia who received inotuzumab, those with MRD-negative CR/CRi had the best survival outcomes.

Pre-Transplant MRD Negativity Predicts Favorable Outcomes of CAR-T Therapy Followed By Haploidentical HSCT for Relapsed/Refractory Acute Lymphoblastic Leukemia: A Multi-Center Retrospective Study

Patients with relapsed/refractory acute lymphoblastic leukemia (R/R ALL) usually have a very poor prognosis and an expected survival of less than 6 months.The complete remission (CR) rates in the setting of the first salvage chemotherapy are about 30% to 46% and these rates drop sharply to 18% to 25% after the second salvage chemotherapy. Chimeric antigen receptor T cells (CAR-T) can induce high CR rates of 70-95% (MRD negative CR rates of 60-90%) among patients with R/R ALL. Howeve, relapse after CAR-T treatment is supposed a main obstacle for long-term outcome. Some reports have described relapse rates of 20-70% when the follow-up was long enough. It remains controversial whether these patients should receive allo-HSCT after CAR-T treatment or not. We designed a multi-center retrospective study to assess the efficacy and safety profiles of CAR-T therapy followed by haplo-HSCT. A total of 31 patients treated with CAR-T therapy followed by haplo-HSCT were included. Eleven patients who progressed to MRD positive or relapse subsequently underwent haplo-HSCT (MRD positive or relapse group) and the rest 20 patients with MRD negativity received haplo-HSCT (MRD negative group). The median time from CAR-T infusion to haplo-HSCT was 83 (range 62-114) days. After a median follow-up period of 288 (range 189-554) days post-transplantation, the 100-day cumulative incidence (CI) of grade III~IV aGVHD was 0% and 10.5% in the MRD positive or relapse group and MRD negative group, respectively (P&gt;0.05)(Figure 1a). One and 2-year CIs of cGVHD requiring systemic steroid therapy were 52.3% and 31.1% (P&gt;0.05), 52.3% and 39.7% (P&gt;0.05) in the MRD positive or relapse group and MRD negative group, respectively(Figure 1b).The 1-year cumulative incidence of CMV viremia was 90.9%, 68.4% and 77.8% in the MRD positive or relapse group, MRD negative group and the whole population respectively (P&gt;0.05). The 2-year cumulative incidence of CMV viremia was 90.9%, 78.9% and 85.2% in the MRD positive or relapse group, MRD negative group and the whole population respectively (P&gt;0.05). The 1-year cumulative incidence of EBV viremia was 90.9%, 79.6% and 84.2% in the MRD positive or relapse group, MRD negative group and the whole population, respectively (P&gt;0.05). And the 2-year cumulative incidence of EBV viremia was 90.9%, 89.8% and 89.5% in the MRD negative or relapse group, MRD negative group and the whole population, respectively (P&gt;0.05). Onset of CMV and EBV viremia occurred in 33.5 (26.3-50.0) days and 44.0 (28.5-57.0) days after transplantation in 24 and 25 patients, respectively. Median peak CMV DNA and EBV DNA load were 1.5X104 (2.6X103-3.4X104) copies/ml and 2.2X104 (1.1X104, 4.1X104) copies/ml, respectively. One and 2-year CIs of relapse were 84.8% and 6.7% (p&lt;0.001), 100% and 15.2% (p&lt;0.01%) in the MRD positive or relapse group and MRD negative group, respectively (Figure 1d). One-year GVHD and relapse free survival (GRFS), leukemia free survival (LFS) and overall survival (OS) in the MRD positive or relapse group and MRD negative group were 18.2% and 58.9% (P=0.024), 15.2% and 93.3% (P&lt;0.001), 43.6% and 100% (P=0.002), respectively (Figure 1f). Two-year GRFS, LFS and OS in the MRD positive or relapse group and MRD negative group were 0% and 50.5% (P=0.007), 0% and 84.8% (P&lt;0.001), 14.5% and 83.3% (P&lt;0.001), respectively (Figure 1c,e,f). No patient died of therapy-associated complications. Relapse or MRD positivity at the time of haplo-HSCT is the only independent factor associated with poor LFS [hazard ratio (HR): 23.6, 95% confidence interval (CI): 2.78-201.63, P=0.004] and OS [HR: 10.4, 95% CI: 1.12-94.45, P= 0.037]. In conclusion, our trial provided data to illustrate the safety and efficacy profiles of a novel combining therapeutic strategy against R/R ALL by using the combination of CAR-T cells for re-induction followed by haplo-HSCT for consolidation. We confirmed that achieving pre-transplant MRD negativity after CAR-T treatment is a suitable basis for haplo-HSCT. Our study results imply that CAR-T therapy followed by haplo-HSCT could further improve LFS and OS without increasing risks of treatment-related toxicity in such a previously heavily treated population. Further evaluation is needed from larger scale studies with a more homogeneous patient population and longer follow-ups. Figure 1 Disclosures Blaise: Jazz Pharmaceuticals: Honoraria; Sanofi: Honoraria; Molmed: Consultancy, Honoraria; Pierre Fabre medicaments: Honoraria. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding.

Efficacy and safety of CD19 chimeric antigen receptor T cells for the treatment of 22 patients with B-cell lymphoma

目的探讨CD19 CAR-T治疗B细胞淋巴瘤的疗效及安全性。方法评估2017年2月1日至2018年7月1日CD19 CAR-T治疗22例B细胞淋巴瘤患者的疗效及不良反应情况。结果22例患者输注CD19 CAR-T后，总体完全缓解（CR）率为45.5%，部分缓解（PR）率为31.8%，总有效率为77.3%。其中12例复发难治患者9例有效，2例达CR，7例PR；10例微小残留病（MRD）阳性患者，8例MRD转阴。全部患者外周血中均检测到CD19 CAR-T细胞在体内增殖，复发难治患者与MRD阳性患者T细胞增殖的达峰时间分别为治疗后第4.5（1~12）天和治疗后第12（5~19）天，外周血CAR-T细胞分别占总的T淋巴细胞的4.02%（2.23%~28.60%）和10.10%（3.55%~24.74%）。MRD转阴患者持续缓解，中位随访8（3~18）个月均未复发，且此组患者有3例联合PD-1抗体治疗，均达CR。复发难治患者中，7例CAR-T治疗后达PR患者疗效保持时间为1.5~6.0个月，PD-1表达率为25.7%~55.3%，5例CAR-T治疗无效患者PD-1均高表达；共有3例患者联合应用PD-1抗体，其中2例有效；2例CAR-T治疗后达CR患者中1例行异基因造血干细胞移植，另1例随访12个月仍持续缓解。22例患者输注CAR-T细胞后14例发生不同程度的细胞因子释放综合征（CRS），其中9例为1级CRS，4例为2级CRS，其中1例复发难治患者发生3级CRS，经糖皮质激素、IL-6抗体治疗后CRS得到控制。治疗有效的17例患者中14例发生CRS，治疗无效的5例患者均未发生CRS。难治复发患者发生CRS的严重程度高于MRD阳性患者。结论CD19 CAR-T在CD19+ B细胞淋巴瘤中取得了疗效。CAR-T联合免疫检查点抑制剂的应用能够更好地提高疗效，CAR-T细胞治疗可作为复发难治患者的挽救治疗，清除B细胞淋巴瘤的MRD效果更好且不良反应小。

Efficacy and Safety of Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT) for 67 Pediatric Patients with High Risk T-Cell Acute Lymphoblastic Leukemia (T-ALL)

Introduction Allo-HSCT is frequently used for the treatment of high-risk T-ALL. But still many questions remain to whom and when we offer allo-HSCT and how to further decrease patients relapse rate. Objectives The efficacy and safety of allo-HSCT including haploidentical transplantation for 67 pediatric high-risk T-ALL are retrospectively analyzed. Methods Between February 2013 and April 2018, consecutive 67 pediatric patients with T-ALL after allo-HSCT were evaluated. The median age was 9 (3-14) years old. Male to female was 53:14. 44 cases in the first complete remission (CR1) were transplanted (6 had persistent minimal residual disease (MRD+) and 38 achieved CR with >2 cycles of chemotherapy or with poor prognostic chromosomal or genetic mutation). Fifteen cases were in CR2, and 8 cases underwent salvage transplantation with non-remission (NR) before transplantation. The donors were identical sibling in 6, unrelated in 15 and haploidentical in 46. Sixty cases underwent transplantation with conditioning regimen including total body irradiation (TBI), cyclophosphamide (CTX) and antilymphocyte globulin (ATG), 7 cases with busulphan (Bu), CTX and ATG. Graft versus-host disease (GVHD) prophylaxis was mainly with cyclosporine or tacrolimus, mycophenolate mofeil and short-course methorexate. Results With the median follow up 22 (2-67) months, all patients were successfully engrafted and had full donor chimerism. The 2-year overall survival (OS) after allo-HSCT was 71.1% and the DFS rate was 70.9%. The 2-year OS and DFS in the CR1 group was better than that of in CR2 group (OS 83.3% vs. 65%, p=0.006; DFS 81.6% vs 60%, p=0.007, Fig.1&2). The 2-year OS and DFS in the salvage group were both 33.3%. In addition, the MRD-negative patients before Allo-HSCT had statistically higher OS and DFS than the MRD-positive group (OS 83% vs. 57.1%, p=0.002; DFS 81.2% vs. 50%, p=0.002, Fig 3&4). 11/67 (16.4%) patients were relapsed with the median relapsed time of 3.3 (2-7) months (5 of 11 relapsed in CR1 group, 2 in CR2 and 4 in salvage group). 11.7% (7/60) relapsed patients had a TBI based conditioning regimen while 57% (4/7) relapsed patients had a non-TBI regimen. 17.9% (12/67) patients developed grade II-IV acute GVHD (aGVHD). Of the 12, 8 cases had grade III-IV aGVHD. Twenty-six in 63 evaluable cases developed chronic GVHD, 9 of whom had extensive cGVHD. 18 patients died at the median time of 6 (1-15) months including 9 from relapsed disease (5/9 in salvage group), 5 from infection, 3 from GVHD and 1 from organ failure. Conclusion Allo-HSCT is a curative modality for high risk T-ALL patients. Both OS and RFS in the MRD-negative CR group prior to allo-HSCT were superior to the MRD-positive CR group or salvage recipients. Patients received a TBI based conditioning regimen may have less recurrence than those treated with non-TBI regimen. Recurrence remains the leading cause of death in high risk T-ALL.

Single-Unit versus Double-Unit Umbilical Cord Blood Transplantation in Children and Young Adults with Residual Leukemic Disease

We previously reported in a French prospective randomized study that transplantation of 2 unrelated cord blood (UCB) units instead of 1 unit does not decrease the risk of transplantation failure but may enhance alloreactivity. Here we evaluated the influence of pretransplantation minimal residual disease (MRD) on leukemia relapse and survival after single- versus double-UCB transplantation (UCBT). Among 137 children and young adults who underwent UCBT in this randomized study, 115 had available data on MRD assessment done immediately before initiation of the pretransplantation conditioning regimen. MRD was considered positive at a level of ≥10-4, which was the case of 43 out of 115 patients. Overall, the mean 3-year survival probability was 69.1 ± 4.4%, and it was not significantly influenced by the MRD level: 70.7 ± 5.4% in MRD-negative (<10-4) patients (n = 72), 71.1 ± 9.4% in MRD-positive patients with 10-4 ≤ MRD <10-3 (n = 26) and 58.8 ± 11.9% in MRD-positive patients with ≥10-3 (n = 17). In the MRD-positive group, the mean risk of relapse was significantly lower in the double-UCBT arm compared with the single-UCBT arm (10.5 ± 7.2% versus 41.7 ± 10.4%; P = .025) leading to a higher mean 3-year survival rate (82.6 ± 9.3% versus 53.6 ± 10.3%; P = .031). This difference was observed only in patients who had not received antithymocyte globulin during their conditioning regimen. In the MRD-negative group, there was no differencebetween the single- and the double-UCBT arms. We conclude that even in cases of positive pretransplantation MRD, UCBT in children and young adults with acute leukemia yields a high cure rate, and that a double-unit strategy may enhance the graft-versus-leukemia effect and survival in these patients.

Molecular Monitoring after Autologous Stem Cell Transplantation and Preemptive Rituximab Treatment of Molecular Relapse; Results from the Nordic Mantle Cell Lymphoma Studies (MCL2 and MCL3) with Median Follow-Up of 8.5 Years

The main objectives of the present study were to monitor minimal residual disease (MRD) in the bone marrow of patients with mantle cell lymphoma (MCL) to predict clinical relapse and guide preemptive treatment with rituximab. Among the patients enrolled in 2 prospective trials by the Nordic Lymphoma Group, 183 who had completed autologous stem cell transplantation (ASCT) and in whom an MRD marker had been obtained were included in our analysis. Fresh samples of bone marrow were analyzed for MRD by a combined standard nested and quantitative real-time PCR assay for Bcl-1/immunoglobulin heavy chain gene (IgH) and clonal IgH rearrangements. Significantly shorter progression-free survival (PFS) and overall survival (OS) was demonstrated for patients who were MRD positive pre-ASCT (54 patients) or in the first analysis post-ASCT (23 patients). The median PFS was only 20 months in those who were MRD-positive in the first sample post-ASCT, compared with 142 months in the MRD-negative group (P < .0001). OS was 75% at 10 years and median not reached in the MRD-negative group, compared with only 35 months in the MRD-positive group (P < .0001). Of the 86 patients (47%) who remained in continuous molecular remission, 73% were still in clinical remission after 10 years. For all patients, the median time from ASCT to first molecular relapse was 55 months, with a continuous occurrence of late molecular relapses. Fifty-eight patients who experienced MRD relapse received rituximab as preemptive treatment on 1 or more occasions, and in this group, the median time from first molecular relapse to clinical relapse was 55 months. In most cases, rituximab converted patients to MRD negativity (87%), but many patients became MRD-positive again later during follow-up (69%). By multivariate analysis, high-risk Mantle Cell Lymphoma International Prognostic Index score and positive MRD status pre-ASCT predicted early molecular relapse. In conclusion, preemptive rituximab treatment converts patients to MRD negativity and likely postpones clinical relapse. Molecular monitoring offers an opportunity to select some patients for therapeutic intervention and to avoid unnecessary treatment in others. MRD-positive patients in the first analysis post-ASCT have a dismal prognosis and thus are in need of novel strategies.

Minimal Residual Disease in Multiple Myeloma Patients: Influence on Indicators of Progression Free Survival

Background. Induction, consolidation of response and maintenance therapy are very effective approaches in the treatment of patients with multiple myeloma (MM). However, the majority of patients will inevitably relapse despite achieving progressively higher complete response (CR) rates. Activation of residual clonal plasmatic cells is a cause of relapse disease. Therefore, the assessment of minimal residual disease (MRD) is a strong prognostic factor for progression-free survival (PFS).Aim. To estimate influence of MRD on PFS indicators in MM patients. Methods. We analyzed 28 patients with MM (median age 56 years, male/female - 1.8:1). 5-color flow cytometry was used for immunophenotyping of bone morrow cells as well as definition of primary tumor cells phenotype and detection of MRD. Such markers as CD38, CD138, CD45, CD19, CD20, CD27, CD56 and CD117 were used to identify clonal plasma cells. In addition, MRD was assessed by FISH analysis in patients with genetic abnormalities; CT-PET carried out to patients with the MRD-negative CR.Results. Patients had bortezomib- or lenalidomide-based programs of therapy. Autologous stem cell transplantation (ASCT) was carried out in 18 patients. Performing ASCT statistically significantly increased frequency of MRD-negative CR (p<.01). Before ASCT MRD-negative CR was reached in 3/28 (10,7%) patients. After ASCT 9/18 (50,0%) patients were transferred to the MRD-negative group (6/9 patients before ASCT had MRD-positive CR, 1/9 - MRD status did not change, 2/9 - stringent CR was reached). One patient with MRD-negative CR had CT-PET positive specific lesions. 19/28 (67,8%) patients were transferred to the MRD-positive group (9/19 patients had CR, 5/19 - VGPR, 5/19 - PR). The median PFS didn’t correlate with ASCT in general and the MRD-positive groups (р>.05). PFS in the MRD-negative group was better than in the MRD-positive group with CR (median was not reached vs median of 63.9 months, respectively; 2-year PFS was 100% vs 77%, respectively) (p=.0048). In addition, we analyzed the influence of CR in the MRD-positive group on PFS. Absence of CR is an inferior prognostic factor and is characterized by decrease of PFS in patients with MRD-positive status. The median PFS in the MRD-positive group with CR was 63.9 months and 26.0 months in the MRD-positive group without CR (VGPR and PR) (p=.049). Genetic abnormalities were detected in 7/26 (26.9%) patients before antimyeloma therapy: t(11;14) - in 5/26 (19.2%), del(13q) - in 3/26 (11.5%), t(4;14) - in 1/26 (3.8%), del(1p) - in 1/26 (3.8%). After treatment patients with CR (MRD-positive and MRD-negative) had normal genetic status by FISH. Only 1/7 patients with MRD-positive PR had residual clone with del(13q).Conclusion. Performing ASCT influences frequency of MRD-negative CR. The PFS indicators (median and 2-year PFS) were higher in the group of MM patients, who had MRD-negative status of the disease compared to than in the MRD-positive group. The FISH method had low sensitivity in detection of residual clone with genetic abnormalities, especially in patients with CR. DisclosuresShuvaev:BMS: Honoraria; Pfizer: Honoraria; Novartis pharma: Honoraria.

Plasmacytoid Dendritic Cell Levels at End of Induction Are Predictive of MRD Clearance and Also Influence Disease Outcome in a Subset of Patients

Introduction:Plasmacytoid dendritic cells (pDCs) are a subset of immune cells that secrete type 1 interferons and serve as antigen presenting cells. In many tumors increased pDC frequencies have been observed and are involved in tumor response initiation. However, there is not much data in acute myeloid leukemia especially in the context of minimal residual disease and outcome. Here we evaluated the frequencies of pDCs in the post induction bone marrow and found a significant correlation with post induction MRD levels. Furthermore, we found that high levels of pDCs in MRD positive patients confer a better overall survival (OS).Methods:All adult (>18 years ) of patients who were treated for AML [other than AML with t(15;17)] were accrued over a 2 year period. All patients received "3+7" induction therapy with daunorubicin and cytarabine. If patients were in morphological CR at end of induction, they either received 3 courses of 12-18 gm/m2 high dose cytarabine (HiDAC) or aBMT if feasible. The presence of MRD was assessed using 8 colour flow cytometry on a post induction bone marrows using CD45, CD36, CD38, CD123, CD33, CD117, CD34, HLADR, CD7, CD56, CD13, CD19, CD16, CD11b, CD15 and CD14. Minimum of 500,000 events were acquired/tube on an 8 colour BD FACS Canto II or a 10 colour BC Navios instruments. Kaluza software (v1.3) was used to analyze the .fcs files. MRD was calculated as a percentage of abnormal leukemic cells per total viable cells as gated in forward scatter v side scatter plot. pDCs were calculated as CD123 bright population which expressed HLA-DR (while gating on the progenitors and monocytes based on their expression of CD45 and side scatter). The pDC percentages were counted as a fraction of all viable cells. pDCs were divided into pDC High and pDC Low groups, based on a median pDC value of 0.1%. OS was calculated from start of induction therapy to time of last follow up or death. Chi Squared test was used to analyse categorical values of pDC (hi v/s low) and MRD (positive v/s negative). Log rank test was used to compare pDC groups in MRD positive subset.Results:At a median follow up of 16 months, OS was 47.8%. After exclusion of induction deaths, a total of 94 patients of adult AML was assessed for the presence of MRD at the end of induction. Of these MRD was detected in 48 (51.1%, range 0.01-40%). pDC values ranged from <0.01% to 1.95% (median 0.15%). Median pDC value in the MRD positive group was lower (0.05%) as compared to the MRD negative group (0.23%). Out of 94 patients of 44.7% patients belonged to the pDC Low group of which majority patients were MRD positive (66.7% of the pDC Low group). Similarly, majority of patients in the pDC High group were MRD negative (61.5% of the pDC High group). A statistical analysis of these categories was found to be significant (p=0.008). When pDCs (high/low) groups were analyzed in each of MRD subsets we found a significant association in MRD positive group (p=0.03), indicating that MRD positive patients who have low pDC levels have a worse OS (median OS: 10.3 months).Conclusion:These pilot data seem to indicate that the pDC burden in the bone marrow may have a role in influencing MRD clearance in the bone marrow. A detailed investigation of the pDC function in the bone marrow microenvironment is warranted. Functional studies on pDCs are warranted to understand the dynamics of disease relapse. [Display omitted] DisclosuresPatkar:Wellcome Trust-DBT India Alliance: Research Funding.

Plasmacytoid Dendritic Cell Burden in the Bone Marrow Predicts End of Induction Minimal Residual Disease Status in Adult Acute Myeloid Leukemia

Introduction:Plasmacytoid dendritic cells (pDCs) are a subset of immune cells that secrete type 1 interferons and serve as antigen presenting cells. In many tumors increased pDC frequencies have been observed and are involved in tumor response initiation. However, there is not much data in acute myeloid leukemia especially in the context of minimal residual disease. Here we evaluated the frequencies of pDCs in the post induction bone marrow and found a significant correlation with MRD levels.Methods:All adult (>18 years ) of patients who were treated for AML [other than AML with t(15;17)] were accrued over a 2 year period. The presence of MRD was assessed using 8 colour flow cytometry on a post induction bone marrows using CD45, CD36, CD38, CD123, CD33, CD117, CD34, HLADR, CD7, CD56, CD13, CD19, CD16, CD11b, CD15 and CD14. Minimum of 500,000 events were acquired/tube on an 8 colour BD FACS Canto II or a 10 colour BC Navios instruments. Kaluza software (v1.3) was used to analyze the .fcs files. MRD was calculated as a percentage of abnormal leukemic cells per total viable cells as gated in forward scatter v side scatter plot. pDCs were calculated as CD123 bright population which expressed HLA-DR (while gating on the progenitors and monocytes based on their expression of CD45 and side scatter). The pDC percentages were counted as a fraction of all viable cells. Based on the results the levels of pDCs were divided into pDC High and pDC Low groups. Statistical analysis was done using Chi squared groups.Results:After exclusion of induction deaths, a total of 94 patients of adult AML was assessed for the presence of MRD at the end of induction. Of these MRD was detected in 48 (51.1%, range 0.01-40%). pDC values ranged from <0.01% to 1.95% (median 0.15%). Median pDC value in the MRD positive group was lower (0.05%) as compared to the MRD negative group (0.23%). Out of 94 patients of 44.7% patients belonged to the pDC Low group of which majority patients were MRD positive (66.7% of the pDC Low group). Similarly majority of patients in the pDC High group were MRD negative (61.5% of the pDC High group). A statistical analysis of these categories was also found to be significant (p=0.008)Conclusion:These pilot data seem to indicate that the pDC burden in the bone marrow may have a role in influencing MRD clearance in the bone marrow. A detailed investigation of the pDC function in the bone marrow microenvironment is warranted. DisclosuresNo relevant conflicts of interest to declare.

The Frequency of Occurrence of Minimal Residual Disease into Different Prognostic Groups of Patients with Chronic Lymphocytic Leukemia

Background. It is known, that genetic factors and the absence of minimal residual disease (MRD) are strongly affecting prognosis of chronic lymphocytic leukemia (CLL).Aim. To determine the influence of genetic abnormalities (GA) on achieving MRD-negative remissions in patients with CLL.Methods. Twenty-four adult pts (median age 57 years, range 35-67; male 14, female 10) with newly diagnosed CLL were included. The CLL was diagnosed according to the standard basic examination (complete blood count with differential, multicolor flow cytometry (MFC) of blood and bone marrow (BM), lymph node and BM immunohistochemistry (IHC), computered tomography). Cytogenetic studies were performed on blood samples using standard GTG-method. Interphase FISH analyses were performed according to the manufacturer's protocol using DNA probes: LSI 13(RB1)13q14, LSI ATM (11q22), CEP12, LSI TP53 (17p13.1) (Abbott). Immunophenotype (IFT) of CLL cells assessed with combinations: CD3/CD19, CD19/CD5, CD19/CD11c, CD19/CD20, CD19/CD22, CD19/CD23, CD19/CD25, CD19/CD38, CD19/CD43, CD19/CD81, CD19/HLA-DR, and CD19/CD5/CD23. We have used NCI revised guidelines (Hallek M, et al., 2008) for treatment initiation and assessment of response after completion of primary therapy with rituximab-based regimens (FCR or RB). All patients treated subsequently with rituximab maintenance. MRD was detected by MFC.Results. The frequency of GA in CLL was 50.0% (12/24): 15.0% (3/20) - by conventional karyotyping, 47.8% (11/23) - by FISH analyses and 9.5% (2/21) - using both methods. Stratification of patients into prognostic groups based on identified GA. Favorable prognosis (Group 1) - patients with del(13q) (n = 5); neutral prognosis (Group 2) - normal karyotype (n = 12) or trisomy of chromosome 12 (n = 3); unfavorable prognosis (Group 3) - del(11q) (n = 3) or the complex karyotype (n = 1).Statistically significant differences in the frequency of achieving MRD-negative remissions between FCR (5/11) vs. RB (5/13) were not detected (p<0.05).Complete remissions (CR) were reached in 37.5% (9/24) pts, partial remissions (PR) - 62.5% (15/24). The MRD-negative remissions were reached in 10 patients: in Group 1 - 2/5 (40%; CR - 1), in Group 2 - 5/15 (33.3%, CR - 6), in Group 3 - 75.0% (3/4; CR - 2).Statistically significant differences in PFS were detected between MRD-negative vs. MRD-positive groups (p=0.03). Median PFS in MRD-negative has not been reached. Median PFS MRD-positive was 33.1 month.Conclusions. Further researches aimed at examining the relationship between the presence or absence of MRD and genetic prognostic groups, will help to understand the most important factors affecting the overall and progression-free survival. DisclosuresNo relevant conflicts of interest to declare.

Prognostic significance of minimal residual disease in high risk B-ALL: a report from Children's Oncology Group study AALL0232

AbstractMinimal residual disease (MRD) is highly prognostic in pediatric B-precursor acute lymphoblastic leukemia (B-ALL). In Children's Oncology Group high-risk B-ALL study AALL0232, we investigated MRD in subjects randomized in a 2 × 2 factorial design to receive either high-dose methotrexate (HD-MTX) or Capizzi methotrexate (C-MTX) during interim maintenance (IM) or prednisone or dexamethasone during induction. Subjects with end-induction MRD ≥0.1% or those with morphologic slow early response were nonrandomly assigned to receive a second IM and delayed intensification phase. MRD was measured by 6-color flow cytometry in 1 of 2 reference labs, with excellent agreement between the two. Subjects with end-induction MRD <0.01% had a 5-year event-free survival (EFS) of 87% ± 1% vs 74% ± 4% for those with MRD 0.01% to 0.1%; increasing MRD amounts was associated with progressively worse outcome. Subjects converting from MRD positive to negative by end consolidation had a relatively favorable 79% ± 5% 5-year disease-free survival vs 39% ± 7% for those with MRD ≥0.01%. Although HD-MTX was superior to C-MTX, MRD retained prognostic significance in both groups (86% ± 2% vs 58% ± 4% for MRD-negative vs positive C-MTX subjects; 88% ± 2% vs 68% ± 4% for HD-MTX subjects). Intensified therapy given to subjects with MRD >0.1% did not improve either 5-year EFS or overall survival (OS). However, these subjects showed an early relapse rate similar to that seen in MRD-negative ones, with EFS/OS curves for patients with 0.1% to 1% MRD crossing those with 0.01% to 0.1% MRD at 3 and 4 years, thus suggesting that the intensified therapy altered the disease course of MRD-positive subjects. Additional interventions targeted at the MRD-positive group may further improve outcome. This trial was registered at www.clinicaltrials.gov as #NCT00075725.

Monitoring minimal residual disease by qualitative detection of immunoglobulin H/T cell receptor γ by using multiplex polymerase chain reaction in children with acute lymphocytic leukemia

Objective To explore the prognostic significance in monitoring minimal residual disease (MRD) in childhood acute lymphoblastic leukemia (ALL) by a simple method, and to detect cloned immunoglobulin H (IgH) and T cell receptor γ (TCRγ) gene rearrangements by using multiplex polymerase chain reaction (PCR) and automated fragment analysis. Methods Bone marrow samples were collected from 86 newly diagnosed cases of childhood ALL at the Department of Pediatrics, the First Affiliated Hospital of Sun Yat-Sen University, from May of 2009 to August of 2013.IgH and TCRγ gene rearrangements were amplified by qualitative multiplex PCR.The clonality of PCR production was analyzed by GENEMAPPERID software.Only those carried monoclonal IgH/TCRγ on diagnosis were arranged to monitor MRD.Detectable monoclonal IgH/TCRγ by the end of induction was defined as MRD positive.All patients were treated with GD2008 ALL protocol.Clinical data of all newly-diagnosed ALL patients in the corresponding period were reviewed.The final follow-up on May 31, 2014.Survival rates and event free survival (EFS) curves were estimated by the Kaplan-Meier, and compared by using the log-rank test. Results The percent age of 94.2(81/86 cases) patients was at least 1 marker positive.Subsequent MRD was monitored in 79 cases.The median follow-up time was 20 months (9-61 months). By the end of induction, 20 cases were MRD positive and 59 cases were MRD negative, and the 3-year EFS were 56.4%±14.7% and 94.0%±3.4% (χ2=8.563, P=0.003), respectively.According to the traditional prognostic stratification criteria, MRD was detected 65 cases in the non-high risk group: 23 cases in stan-dard risk group and 42 cases in intermediate risk group, and the difference of 3-year EFS had no statistical significance (95.3%±4.7% vs 76.6%±9.0%, χ2=0.934, P=0.334). While using MRD by the end of induction as a risk stratification criterion, there was a statistical significant difference compared with the 3-year EFS for MRD-negative (n=52) group and MRD-positive (n=13) group(93.1%±3.8% and 59.5%±16.2%, χ2=7.128, P=0.008). Conclusions It is a simple but feasible method to monitor MRD in childhood ALL by using this qualitative multiplex PCR with automated fragment analysis for monoclonal IgH/TCRγ gene rearrangements.MRD by the end of induction can be used as a more accurate risk stratification criterion than the traditional one.It is worth of further research. Key words: Acute lymphoblastic leukemia; Prognosis; Minimal residual disease

Concordance and Prognostic Significance of Minimal Residual Disease Detection in Peripheral Blood and Bone Marrow Samples of Infants with MLL-rearranged Acute Lymphoblastic Leukemia Treated By MLL-Baby Protocol

Background. Minimal residual disease (MRD) is powerful tool for prediction of treatment outcome in leukemia patients of various age groups, including infants with acute lymphoblastic leukemia (ALL). In the vast majority of cases only bone marrow (BM) samples are used for MRD detection.Objective. To estimate prognostic significance of MRD in peripheral blood (PB) and BM by qualitative detection of different MLL fusion gene transcripts in infant ALL enrolled into MLL-Baby protocol.Methods. Fifty three infants (20 boys and 33 girls) with median age of 5.3 months (range 0.03-11.80) and defined MLL rearrangements were included in the current study. Among them there were 25 patients (47.2%) carrying MLL-AFF1 fusion gene transcripts, 10 (18.9%) MLL-MLLT3-positive cases, 9 (17.0%) MLL-MLLT1-positive cases, 5 (9.4%) MLL-MLLT10-positive cases and 4 (7.5%) MLL-EPS15-positive ones. MRD evaluation was performed by detection of MLL fusion gene transcripts in BM and PB samples using real-time PCR and nested RT-PCR with sensitivity non-less than 1E-04. MRD-negativity was defined as absence of fusion gene transcripts in both assays. Median of follow-up period in the observed group was 5.2 years. Time points (TP) for MRD assessment were as follows: day 15 of remission induction (TP1), at the end of remission induction (TP2), after each course of ATRA administration (TP3-TP7). Informed consent was obtained in all cases.Results. We estimated 142 paired BM/PB samples. 77 samples were double positive, 43 were double negative Thus concordance between MRD results in BM and PB samples achieved 84.5%. Concordance varied between different TPs of MLL-Baby protocol from 79.0% to 100%. The highest concordance rate was at TP4 and TP7 (92.3% and 100%, respectively). Interestingly, all discrepant results (22 samples 15.5%) were BM-positive/PB-negative. Median level of ABL gene, used for normalization, was similar in BM and PB samples (4.85E+04 vs 4.95E+04, respectively, p=0.760). Evaluation of prognostic significance of MRD in BM in TP1-TP7 revealed that TP4 was the earliest TP when discriminative data between MRD-positive and MRD-negative patients were obtained. MRD-positivity at TP4 in BM led to unfavorable outcome. Event-free survival was significantly lower in MRD-positive group (n=22) in comparison to MRD-negative one (n=31) (0.06±0.06 vs 0.70±0.09 p=0.0001), while cumulative incidence of relapse in MRD-positive patients was remarkably higher (0.92±0.01 vs 0.29±0.08, p<0.0001). MRD-positivity at this TP in BM was the only significant factor in the diagnostic model where initial risk factors (age at diagnosis, initial WBC count, immunophenotype, CNS disease, presence of MLL-AF4) were combined to response criteria (number of blast cells at day 8 of dexamethasone prophase and MRD in BM at TP4) (Table). The only TP when MRD data obtained from PB samples had prognostic value was TP6. In this TP cumulative incidence of relapse in MRD-positive patients was significantly higher in comparison to MRD-negative ones (0.88±0.11 vs 0.25±0.13, respectively, p=0.003). However these data did not bring any extra advantages as compared to TP4 in BM.Conclusions. Despite high qualitative concordance rate between MRD detection in BM and PB samples we could not show prognostic value of MRD monitoring in PB by fusion gene transcripts. Univariate and multivariate analysis revealed that MRD-positivity at TP4 in BM was the only significant and independent prognostic factor of unfavorable outcome in the observed group of patients. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Pre-transplant MRD predicts outcome following reduced-intensity and myeloablative allogeneic hemopoietic SCT in AML

The presence of minimal residual disease (MRD) by multiparametric flow cytometry (MFC) has been associated with adverse outcomes in AML patients treated with chemotherapy alone, but its impact in the setting of allogeneic hematopoietic SCT (HSCT) is less clear. We studied 88 patients who underwent myeloablative (MA) or reduced-intensity conditioned allogeneic HSCT for AML in first or subsequent remission at our center. MRD status was determined using three-color MFC on pre-HSCT BM aspirates, and patients were stratified by MRD status into MRD-negative, low-level MRD-positive (<1%) or high-level MRD-positive groups (1-4.9%). Two-year survival estimates in these groups were 66.8%, 51% and 30%, respectively (P=0.012), and 2-year estimates of relapse were 7.6, 37 and 70% (P<0.001). Pre-HSCT MRD was related to disease characteristics including secondary AML (P=0.002) and primary induction failure (P=0.005), but, despite these strong correlations, MRD remained independently associated with poorer survival in multivariate analysis (hazard ratio, 1.92; P=0.014). Pre-HSCT MRD is associated with adverse clinical outcomes in AML patients undergoing reduced-intensity or MA HSCT in first or subsequent remission and should be integrated into transplant strategies for patients with AML.

Prognostic Value Of Deep Sequencing Approach For Minimal Residual Disease (MRD) Detection In Multiple Myeloma Patients

Background and AimMost multiple myeloma (MM) patients will experience relapse due to the persistence of residual tumor cells, or MRD. We compared the prognostic value of traditional response criteria with MRD measured by three different methods: a sequencing-based method, termed the LymphoSIGHT™ platform, multiparameter flow cytometry (MFC) and ASO-PCR of Ig genes in a cohort of 133 uniformly-treated MM patients from the Spanish Myeloma Group trials. MethodsBone marrow samples were obtained from 133 patients at diagnostic and post-treatment time points on GEM clinical trials (GEM00 and GEM05). All 133 patients were either in CR or VGPR at the post-treatment time point. Using the sequencing assay, we identified clonal rearrangements of immunoglobulin (IGH-VDJ, IGH-DJ, and IGK) genes in diagnostic samples. We then assessed MRD in follow-up samples, analyzing concordance between: sequencing, MFC and ASO-PCR of Ig genes MRD results, and comparing the prognostic value of each method with traditional response criteria. ResultsThe sequencing assay detected the presence of a myeloma-specific gene rearrangement in diagnostic samples from 121 of 133 (91%) patients. We tested MRD in follow-up time points in 109 of the 121 patients.Of the 109 patients, 79 were positive by sequencing at MRD levels of 10-5 or higher and 30 were MRD negative. The Time to Tumor Progression (TTP) and Overall Survival (OS) were significantly longer in the MRD negative group compared with the MRD positive group by sequencing (TTP, median 80 vs. 31 months, p<0.0001; and OS, median not reached vs. 80 months p=0.02) (Figures 1A and 1B). All patients in VGPR, with the exception of 4 cases, were MRD positive by sequencing (92%). Three of the 4 cases with MRD negative and positive immunofixation became immunofixation negative after maintenance treatment. When restricting the analysis to the 61 patients that were in conventional CR (negative immunofixation), 35 of 60 patients were positive by sequencing at MRD levels at 10-5 and higher and 26 were MRD negative. There was a significantly improved TTP in the MRD negative group compared with the MRD positive group (median 131 vs. 35 months, p=0.001) (Figure 1C).A high correlation between MFC and sequencing MRD results was observed (r2=0.87); as well as between ASO-PCR of Ig genes and sequencing (r2=0.89). Discordant results between FCM and sequencing (SEQ) included: 14 cases who were positive by SEQ and negative by FCM, and 5 cases negative by SEQ but positive by FCM; while the remaining cases were concordant: 63 cases were positive by both methods and 16 were negative by both methods. Correlation between ASO-PCR and SEQ was possible in 45 patients: 10 were discordant (9PCR-SEQ+ and 1 PCR+SEQ-) while 35 were concordant (20 PCR+SEQ+, 15 PCR-SEQ-). [Display omitted] ConclusionsThe sequencing applicability for MRD studies in MM is 91%, which is essentially equivalent with that of MFC (96% Rawstron AC et al, JCO 2013). There is a high correlation between MRD levels by sequencing, ASO-PCR and MFC. Based on these results, MRD assessment by sequencing is a useful method for patient risk stratification and can be used to determine molecular CR in MM. Disclosures:Pepin:Sequenta, Inc.: Employment, Equity Ownership. Weng:Sequenta, Inc.: Employment, Equity Ownership. Faham:Sequenta, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Value of Pretransplantation Minimal Residual Disease in Acute Myeloid Leukemia and Myeloablative Hematopoietic Cell Transplantation.

AbstractAbstract 2510Relapse remains the main cause of treatment failure in patients with acute myeloid leukemia (AML) in first remission (CR1) after allogeneic hematopoietic stem cell transplantation (SCT). The detection of minimal residual disease (MRD) in AML has improved in the past years with multiparametric flow cytometry (MFC) and molecular analysis (RT-PCR). However the prognostic impact of pre-transplantation MRD and the outcome after SCT has not been well studied. The aim of this study was to evaluate pre-transplantation MRD in patients in first remission undergoing myeloablative allogeneic SCT.We retrospectively studied 35 consecutive patients receiving myeloablative SCT for AML in first cytologic remission after intensive chemotherapy with available MRD determination before transplant. MRD was studied by 4-color MFC on bone marrow aspirates, and quantitative RT-PCR (NPM1, WT1, MLL) on bone marrow and/or peripheral blood samples obtained within thirty days before transplant.Thirty-five patients consecutively transplanted in our institution between 1999 and 2012, and for which pre-transplant MRD data was available were analyzed (Table 1). Eighteen showed negative MRD pre-transplant whereas 17 showed positive values. Characteristics of patients were homogeneous between both groups, including number of chemotherapy cycles received before transplantation (Table 1).Within the MRD-negative group, 17 patients showed negative MRD by MFC (12 of them showed negative values also by PCR) and 1 patient showed negative MRD by PCR (MFC not available). Within the MRD-positive group, 9/17 (52%) patients showed MRD-positive values by MFC: in 5 cases MRD was also detected by PCR, only 1 showed negative PCR and in the remaining 3 cases, PCR was not available. On the other hand, in 8/17 (47%) patients MRD was not detected by MFC, however, PCR detected MRD in all of the cases in bone marrow (2), peripheral blood (4) or both samples (2).With a median follow-up of the whole series of 23 months, 2-years estimates of overall survival were 82% (95% CI, 97–55) and 30% (95% CI, 3–71) for MRD-negative and MRD-positive patients (p=0.045), respectively. Cumulative incidence of relapse were 21% (95% CI, 5–48) and 56% (95% CI 10–73) for MRD-negative and MRD-positive patients (p=0.11).In the MRD-negative group, cause of death was toxicity in 11% of the cases and relapse in 11%, while in the MRD-positive group, 17% of patients died due to toxicity and 23% due to relapse.Conclusions: Our data shows that the presence of MRD before allogeneic SCT in patients with AML in CR1 is associated with a significant worse OS rate compared to patients with negative MRD, as well as a tendency towards a higher risk of relapse. The detection of MRD by MFC correlates with the detection by PCR in most of the cases. However, in a significant group of patients, MRD was detected only by PCR. This could be related to differences in sensitivity between both methods. Further studies including larger series are needed to confirm these observations.Table 1Patient and Disease Characteristics by MRD statusPre-transplant MRDMRD-negativeMRD-positiveN=351817Age at transplant (median, R)36 (19-62)42 (19-68)Gender (male/female)8/1012/5Cytogenetics and molecular markersNormal/Intermediate risk77%83%FLT3+28%27%NPM1+/FLT3-6%7%FLT3-/NPM1-28%40%High-risk22%17%Secondary AML16%6%Cycles pre-transplantation (median, R)3 (2-5)3 (2-5)MRD detectionMFC only27%18%RT-PCR only5%0%Both68%82%Donor*HLA-identical sibling50%35%HLA-matched unrelated22%29%SCU-dual22%24%HLA-haploidentical related6%12%acute GVHD II-IV (n°/patients at risk)44% (8/18)24% (4/17)chronic GVHD lim/ext (n°/patients at risk)53% (8/15)57% (8/14)MRD: minimal residual disease, MFC: multiparametric flow cytometry, RT-PCR: real time PCR, GVHD: graft vs host disease, SCU-dual: single cord blood with co-infusion of selected CD34+ cells from a third party HLA-mismatched donor.*The MRD negative group includes 2 MAC SCU-dual cases with primary graft failure rescued immediatly by a second graft (1 Dual and 1 Haplo) using a RIC regimen. The MRD positive group includes 1 MAC SCU-dual case rescued immediatly by a second graft (1 Haplo). Disclosures:No relevant conflicts of interest to declare.

Minimal Residual Disease in Adults with Advanced Relapsed Philadelphia Chromosome Negative Acute Lymphoblastic Leukemia Treated with Marqibo® (vinCRIStine sulfate LIPOSOME injection)

AbstractAbstract 4805Minimal residual disease (MRD) testing in acute lymphoblastic leukemia (ALL) has been primarily used in the frontline treatment setting following achievement of morphologic remission where absence of detectable disease (molecular remission) may predict for a more favorable outcome. Potential utility of post-induction MRD testing in the advanced, relapsed/refractory adult Philadelphia chromosome (Ph) negative ALL setting has not been reported.We assessed MRD in the pivotal Phase 2 RALLY Study (HBS407, NCT00495079) of weekly high-dose (2.25 mg/m2 without any dose cap) vincristine sulfate liposome injection (VSLI, Marqibo®) monotherapy in 65 patients with either B- or T-cell lineage, Ph-negative ALL in 2nd or greater relapse or that had progressed following 2 or more lines of prior anti-leukemia therapy. All patients were heavily pretreated, all had received prior standard vincristine (VCR), 48% had undergone a prior hematopoietic cell transplant, and 43% were refractory to their immediate prior line of therapy. The median bone marrow blast percentage at presentation was 82%.Complete response (CR) or CR with incomplete hematologic recovery (CRi) was achieved in 13 (20%) patients based on principal investigator (PI) assessment (predefined primary endpoint) and in 11 (17%) patients as assessed by an independent response review committee (IRRC). Two patients assessed as CR/CRi by a PI were classified as bone marrow blast (BMB) responders (morphologic remission lacking neutrophil and platelet count recovery) by the IRRC. MRD data from the first bone marrow demonstrating VSLI-induced CR/CRi based on site-specific flow cytometry methodology were available in 12 of the 13 CR/CRi patients. Molecular remission was confirmed in 8 of 12 (67%) patients. Response and VSLI treatment details for the MRD-negative and MRD-positive groups are provided in the tableMRD Negative N = 8MRD Positive N = 4PI Response AssessmentCR51CRi33BMB Responder00IRRC AssessmentCR61CRi03BMB Responder20Response Duration, Median (Range)140 days (32–162)87 days (35–210)Overall Survival, Median (Range)230 days (121–321)203 days (71–327)VSLI Doses, Median (Range)9 (4–18)5 (4–10)VSLI Exposure (mg of VCR), Median (Range)35.9 (17.4–58.6)20.1 (15.8–33.4)Most (83%) patients who achieved a CR were MRD-negative. Half of the CRi patients, based on PI assessment, were MRD-negative. Both of the BMB responders, based on IRRC assessment, were MRD-negative. Median response duration, overall survival, number of VSLI doses, and cumulative VSLI dose expressed as milligrams of VCR were larger in patients who were MRD-negative.VSLI monotherapy administered as a third-, fourth-, or fifth-line therapy in adults with advanced, relapsed/refractory Ph-negative ALL was able to induce morphologic remission in 13 of 65 (20%) of patients and molecular remission in 8 of 12 (67%) evaluable morphologic remissions. MRD negativity may result from greater VSLI exposure and may be associated with more favorable response durations. MRD assessment may help to determine remission status particularly in patients with morphologic remission and incomplete recovery of either (i.e., CRi) or both (i.e., BMB Response) the peripheral blood platelet count and neutrophil count secondary to extensive prior myelotoxic therapy. Disclosures:Goldberg:Eisai: Speakers Bureau. Silverman:Talon Therapeutics: Employment. Deitcher:Talon Therapeutics: Employment, Equity Ownership.