Low incidence of hepatic veno-occlusive disease (VOD) in patients with B-cell acute lymphoblastic leukemia (B-ALL) treated with inotuzumab ozogamicin (INO) followed by allogeneic stem cell transplantation (allo-SCT).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e19024-e19024
Author(s):  
Kirk Cahill ◽  
Juan Alban ◽  
Mylove Mortel ◽  
Emily Dworkin ◽  
Satyajit Kosuri ◽  
...  
Keyword(s):  
Salvage Therapy ◽  
Lymphoblastic Leukemia ◽  
Antifungal Prophylaxis ◽  
Data Sets ◽  
Subsequent Cycle ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Conditioning Regimens ◽  
Low Incidence ◽  
The University

e19024 Background: Hepatic VOD is an uncommon, but often fatal complication of allo-SCT. The risk is increased after INO, an anti-CD22 antibody conjugated to calicheamicin with high remission rates in relapsed CD22-positive B-ALL. Previous reports have described VOD rates as high as 19% in INO-treated patients who then received allo-SCT. We report our safety experience using INO followed by allo-SCT. Methods: We identified patients >18 yrs with B-ALL treated with allo-SCT and INO in the University of Chicago IRB-approved SCT database. We reviewed the EMR for patient details, toxicities (CTCAE v5.0), and outcomes. Hepatic VOD was defined according to EBMT criteria. Overall survival (OS) was from time of allo-SCT to death or last follow-up. Results: Between 2010-2021, 72 adult patients with B-ALL received allo-SCT, and 17 also received INO as salvage therapy (Table). Median follow-up was 19 months (1-110). All received ursodiol prophylaxis and 15/17 received an azole for antifungal prophylaxis. They had median 2 cycles (1-3) of INO with median of 1.9 months (1-14) from the last dose of INO to allo-SCT. For cycle 1, 13/17 (77%) received 0.8 mg/m2 on D1 and 0.5 mg/m2 on D8 and D15. Of these, 11 had a subsequent cycle (5 with same dosing and 7 had 0.5 mg/m2 on D1, D8, and D15). 1 patient had 0.5 mg/m2 on D1, D8, and D15 for 2 cycles. 3 patients received 0.8 mg/m2 on D1 and 0.4 mg/m2 on D8 and D15 for 2 cycles. After INO, 10 patients achieved CR and 3 had CRi for ORR of 13/17 (76%). The 4 patients with persistent disease despite INO went into remission with a different salvage therapy prior to allo-SCT. Conditioning regimens are listed in Table 1. No patients developed VOD after allo-SCT. Within 2 yrs of allo-SCT, 3/17 (18%) relapsed and 7/17 (41%) died. The median OS was 21.2 months [18 - NR]. Conclusions: Limiting the number of INO cycles (median 2) prior to allo-SCT, delaying allo-SCT for 2 months after INO exposure, and avoiding dual alkylating agent conditioning may have contributed to the absence of VOD in our patients. Larger data sets will be useful to validate these important safety observations.[Table: see text]

Inotuzumab Ozogamicin (IO) Is An Effective Salvage Therapy That Allows for Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) in Remission in Patients with Advanced Acute Lymphoblastic Leukemia (ALL)

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3102-3102
Author(s):  
Partow Kebriaei ◽  
Kaci Wilhelm ◽  
Farhad Ravandi ◽  
Rima M. Saliba ◽  
Marcos De Lima ◽  
...  
Keyword(s):  
Stem Cell ◽  
Acute Lymphoblastic Leukemia ◽  
Hematopoietic Stem Cell Transplantation ◽  
Salvage Therapy ◽  
Lymphoblastic Leukemia ◽  
Unrelated Donor ◽  
Inotuzumab Ozogamicin ◽  
Hematopoietic Stem ◽  
Conditioning Regimens

Abstract Abstract 3102 No highly effective salvage therapy exists for patients with relapsed acute lymphoblastic leukemia (ALL). Inotuzumab ozogamicin (IO) is a CD22 monoclonal antibody attached to calicheamycin and targets B lymphocytes in early stages of development. A 56% overall response rate was noted in a Phase I study of single agent IO in patients with refractory ALL (Jabbour ASCO 2011), enabling subsequent transplant in remission in a relatively large number of patients. Of note, in the year prior to the availability of IO, we consulted on 13 patients will ALL beyond second remission and transplanted 5 (38%), and after the availability of IO, we consulted on 41 patients and transplanted 27 (67%). Methods: We describe our findings in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT) following treatment with IO between June 2010 and May 2011. IO was administered at 1.8 mg/m2 IV every 3 weeks. Results: 19 patients with median age 32 years (range 5–60) received an allogeneic matched sibling (n=6), matched unrelated donor (n=8), mismatched unrelated donor (n=4), or cord blood HSCT (n=1) in complete remission (CR) (n=2), CR without platelet recovery (n=14), and active disease (n=3); 10 patients were MRD negative at time of HSCT as determined by multiparameter flow cytometry. Patients had received 2 (n=3), 3 (n=9), 4 (n=4), 5 (n=2), or 6 (n=1) lines of salvage therapy prior to HSCT, including 3 patients who had received a prior allogeneic HSCT; IO was the last agent in 17 patients (2 patients refractory to IO received other therapy prior to HSCT). Patients received 1 (n=1), 2 (n=9), 3 (n=6), 4 (n=2), or 5 (n=1) courses of IO a median of 35 days (range 18–69) prior to transplant conditioning with busulfan (Bu) and colafarabine (Clo) (n=8), BuClo+ thiotepa (TT) (n=4), fludarabine (Flu) and melphalan (Mel) (n=1), FluMelTT (n=3), or etoposide and total body irradiation (TBI) (n=3); GVHD prophylaxis was tacrolimus-based for all patients, with post-HSCT cyclophosphamide added for patients receiving mismatched unrelated donors. With a median follow-up of 3 months among surviving patients (0.6–8.2), overall and progression-free survival is 59% at 3 months. There were 11 deaths, 6 from relapse, 4 from multi-organ failure involving VOD, and 1 from pneumonia. Transient liver enzyme elevations were noted in all of the patients, with 26% (n=5) patients developing VOD. The development of VOD was associated with greater lines of prior therapy prior to HSCT (3–5 lines prior salvage therapy, including 2 patients who had a prior allo-HSCT) and more intense transplant conditioning regimens (4 of the 5 patients received BuCloTT or FluMelTT). Conclusions: IO is an effective salvage therapy in patients with advanced ALL, allowing more patients to receive HSCT with encouraging response rates. Longer follow-up is needed to more completely assess disease control. Using reduced intensity HSCT conditioning regimens and avoiding multiple lines of prior therapies may result in less hepatic toxicity. Disclosures: O'Brien: Pfizer: Consultancy. Kantarjian:Pfizer: Research Funding.

scholarly journals A Feasibility and Safety Study of Non-Viral Genome Targeting Anti-CD19 CAR-T in Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 19-20
Author(s):  
Yi Wang ◽  
Hui Wang ◽  
Ying Gao ◽  
Ding Zhang ◽  
Yan Zheng ◽  
...  
Keyword(s):  
T Cells ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Phase I ◽  
Lymphoblastic Leukemia ◽  
Car T Cells ◽  
Car T Cell ◽  
Car T ◽  
Cell Acute Lymphoblastic Leukemia

Introduction: It has been made great clinical progresses in hematological malignancies by chimeric antigen receptor (CAR) T cell therapy which utilizes virus vector for manufacture. However, there're still issues unresolved, for instance, sophisticated virus production process, deadly Cytokine Release Syndrome (CRS) side-effect, and high recurrence rate, which probably limit the availability of CAR-T therapy. Non-viral Genome Targeting CAR-T (nvGT CAR-T) may provide a feasible solution to those unmet needs mentioned above. We used CRISPR-Cas9 and non-viral vector to insert anti-CD19 CAR DNA to a specific genome locus in human T cells, which in theory, produces more moderate CAR-T cells compared with conventional CAR-T cells. The efficacy of anti-CD19 nvGT CAR-T cells had been demonstrated in our previous pre-clinical studies, and in this Phase I clinical trial (ChiCTR2000031942), its safety and efficacy in relapsed/refractory B-Cell Acute Lymphoblastic Leukemia (r/r B-ALL) patients were explored. Objective: The primary objective of this Phase I trial is to assess safety, including evaluation of adverse events (AEs) and AEs of special interest, such as CRS and neurotoxicity. Secondary objective is to evaluate efficacy as measured by the ratio of complete remission (CR). Method: Peripheral blood mononuclear cells were collected from patients or allogeneic donors, then CD3+ T cells were selected and modified by nvGT vector to produce anti-CD19 CAR-T, then administrated to patients with r/r B-ALL. Up to July 2020, twelve patients with r/r B-ALL had been enrolled in this study and 8 patients completed their treatments and entered follow-up period. For 8 patients with follow-up data, the median age was 33 years (range, 13 to 61), and the median number of previous regimens was 5 (range, 2 to 11). The median baseline percentage of bone marrow (BM) blast is 72% (range, 24.5% to 99%). Among those subjects, 2 patients once have been conducted autologous or allogeneic hematopoietic stem cell transplantation (Auto-HSCT or Allo-HSCT), and 2 patients experienced serious infection before CAR-T infusion. No patient has been treated by any other CAR-T therapy before enrollment. Baseline characteristics refer to Table 1. Administering a lymphodepleting chemotherapy regimen of cyclophosphamide 450-750 mg/m2 intravenously and fludarabine 25-45 mg/m2 intravenously on the fifth, fourth, and third day before infusion of anti-CD19 nvGT CAR-T, all patients received an infusion at dose of 0.55-8.21×106/kg (Table 1). Result: Until day 30 post CAR-T cell infusion, 8/8 (100%) cases achieved CR and 7/8 (87.5%) had minimal residual disease (MRD)-negative CR (Table 1). Anti-bacterial and anti-fungal were performed in patients SC-3, SC-4 and SC-5 after CAR-T cell infusion, which seems no influence on efficacy. Patient SC-7 was diagnosed as T-cell Acute Lymphoblastic Leukemia before Allo-HSCT but with recent recurrence of B-ALL, which was MRD-negative CR on day 21 post nvGT CAR-T therapy. Up to July 2020, all cases remain CR status. CRS occurred in all patients (100%) receiving anti-CD19 nvGT CAR-T cell, including 1 patient (12.5%) with grade 3 (Lee grading system1) CRS, two (25%) with grade 2 CRS, and 5 (62.5%) with grade 1 CRS. There were no cases of grade 4 or higher CRS (Table 1). The median time to onset CRS was 9 days (range, 1 to 12 days) and the median duration of CRS was 6 days (range, 2 to 9 days). None developed neurotoxicity. No fatal or life-threatening reactions happened and no Tocilizumab and Corticosteroids administered following CAR-T treatment. Data including body temperature (Figure 1), CAR-positive T cell percentage (Figure 2), Interleukin-6 (IL-6) and Interleukin-8 (IL-8) (Figure 3 and 4), C-reactive Protein (CRP) (Figure 5), Lactate Dehydrogenase (LDH) (Figure 6), and Procalcitonin (PCT) (Figure 7), are in accordance with the trend of CRS. Conclusion: This Phase I clinical trial primarily validates the efficacy of this novel CAR-T therapy, however, it still needs time to prove its durability. Surprisingly, we find that nvGT CAR-T therapy is seemingly superior than viral CAR-T therapy in terms of safety. All subjects which are high-risk patients with high tumor burden had low grade CRS, even a few patients sent home for observation post infusion with limited time of in-patient care. Furthermore, patients could tolerate a higher dose without severe adverse events, which probably bring a better dose-related efficacy. Disclosures No relevant conflicts of interest to declare.

Long-Term Follow-Up Results of Adults with T-Cell Acute Lymphoblastic Leukemia (T-ALL)-The Vancouver Experience.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4578-4578
Author(s):  
Yasser R. Abou Mourad ◽  
Stephen H. Nantel ◽  
Cynthia L. Toze ◽  
Thomas J. Nevill ◽  
Michael J. Barnett ◽  
...  
Keyword(s):  
Induction Chemotherapy ◽  
Mediastinal Mass ◽  
Lymphoblastic Leukemia ◽  
Salvage Chemotherapy ◽  
Free Survival ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Ecog Ps ◽  
Significant Factors

Abstract T-cell acute lymphoblastic leukemia (T-ALL) is a rare disease accounting for approximately 20–25% of adult cases of ALL. The outcome of adult T-ALL has improved in the past decades, but relapse remains the major cause of treatment failure. Few studies have reported on the long-term outcome of adults with T-ALL. We retrospectively reviewed the charts of 39 adult patients (pts) diagnosed with T-ALL and treated at our center between August 1986 and April 2004. Characteristics: Male/female ratio was 3.3/1. Median age was 28.4 years (16.8–73.2). ECOG PS: 0/1(n=27), ≥ 2 (n=12). Median WBC at diagnosis was 12.2 (0.9–445), Platelets 60.7 (6–270), LDH <2 x normal (n= 14), ≥ 2 x normal (n=23), unknown (n=2). CSF was involved in 7/39 pts, splenomegaly found in 13/39, mediastinal mass in 16/39 and lymphadenopathy in 16/39 pts. 36/39 pts received a consistent induction chemotherapy regimen consisting of prednisone, vincristine and daunorubicin ± L-asparaginase. A second phase of induction comprised of cyclophosphamide, cytarabine, methotrexate and mercaptopurine. Intensification was with dexamethasone, vincristine, daunorubicin, cyclophosphamide, cytarabine and thioguanine. Four cycles of consolidation with cytarabine and tenoposide were given. 30/39 pts (77%) achieved complete remission with induction chemotherapy. 1 patients died during induction chemotherapy secondary to disseminated aspergillosis, 2 patient during consolidation secondary to cerebral edema and aspergillosis. 8/30 pts proceeded to allogeneic BMT in CR1(4/8 due to high WBC>150, 3/8 MRD availability,1/8 in CR1 after salvage chemotherapy) of whom two pts died due to aGVHD and infection after transplantation. 8 pts had refractory disease; Only 1/8 achieved CR on salvage chemotherapy. 16/30 (53%) relapsed of whom 12/16 (75%) died of disease progression, 1 died of sepsis in CR2 and 3 pts alive in CR2. Median follow up of the 15 surviving patients is 59 months (1.5–183.4). Results: Overall survival (OS) and event-free survival (EFS) at 3 years for all patients were 33.7% (95% CI 19–49%) and 28% (95% CI 13–43%) respectively. Using univariate analysis, significant factors for poor survival were CSF involvement: [3-year EFS was 14% vs 34% (p = 0.05)], LDH levels higher than 2 times normal [3-year EFS was 7% vs 43.5% (p = 0.005)] and ECOG PS ≥2: [3-year EFS was 16.6% vs 37% (p = 0.05)]. Non-significant factors included sex, age < 30 vs 30–55, presence of mediastinal mass, lymphadenopathy, splenomegaly, WBC > 50. Conclusions: Adult T-ALL presents more commonly in young males with a third having a mediastinal mass. The outcome of treatment results in a 30% long term disease free survival. Patients refractory to induction as well as those who relapse have poor prognosis. As expected poor PS, high LDH and CSF involvement dictates worse outcome. Neither age, nor high WBC count contributed to worse prognosis.

Nelarabine Is Safe and Effective In Adult Relapsed or Refractory T Cell Acute Lymphoblastic Leukemia (T-ALL) and Lymphoblastic Lymphoma (T-LBL): The Bologna Experience

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4250-4250
Author(s):  
Cristina Papayannidis ◽  
Ilaria Iacobucci ◽  
Mariachiara Abbenante ◽  
Annalisa Lonetti ◽  
Viviana Guadagnuolo ◽  
...  
Keyword(s):  
Safety Profile ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Hematological Toxicity ◽  
Induction Treatment ◽  
Mutational Status ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Relapsed Disease ◽  
Integrated Program

Abstract Abstract 4250 Background. Nelarabine (N) is approved for the treatment of T-ALL and T-LBL that have not responded to or has relapsed after treatment with at least 2 chemotherapy regimens. Aim. To evaluate safety profile and efficacy of N as savage therapy in 16 adult relapsed or refractory T-ALL or T-LBL. Methods. After obtaining an informed consent, 16 patients (median age 33 years, range 19–45, M/F= 13/3) affected by T-ALL (n=10) and T-LBL (n=6) received savage therapy with N (median cycle=1, range 1–3), administered at standard adult dosage (1500 mg/sqm on days 1, 3 and 5, every 21). Four patients were primary resistant to induction treatment, 7 patients were relapsed after two previous chemotherapy regimens (including allogeneic BMT in 4 cases and autologous SCT in 1 case); the remaining 6 patients had a molecular relapsed disease (MRD positive). Molecular characterization was performed, including NOTCH and WT-1 genes mutational status. GEP analysis, according to Ferrando A. stratification (Cancer Cell 2002), is still ongoing. Results. Currently, 12 out of 16 patients are evaluable, due to a too short follow up in the other 4 cases. Seven out of 12 patients obtained a complete remission (CR) (5 T-ALL 2 T-LBL);a partial remission (PR) was documented in 2 cases, with an overall response rate (ORR) of 75%. Median duration of CR was 10 weeks (range 2.8–54+). Among these, 2 out of 4 patients in molecular relapse reached a molecular CR and underwent an allogenic BMT (currently in CR after a median follow up of 12 months). Extra- hematological toxicity, not clearly related to the drug, occurred in 3 cases, determining, a complete and irreversible paraplegia, a condition of mental confusion, and a peripheral neuropathy, respectively. Conclusions. N showed a strong efficacy also in cases with low levels of residual disease, in addition to a good safety profile. Neurological toxicity needs to be strictly monitored. Acknowledgments. European LeukemiaNet, AIL, AIRC, Fondazione Del Monte di Bologna e Ravenna, FIRB 2006, PRIN 2008, PRIN 2009, Ateneo RFO grants, Project of integrated program (PIO), Programma di Ricerca Regione – Università 2007 – 2009. Disclosures: Baccarani: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Martinelli:Pfizer: Consultancy; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria.

scholarly journals Immunotherapy for T-Cell ALL and T-NHL: Highlights From SOHO 2020

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Allyson Price, MPAS, PA-C
Keyword(s):  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Cancer Center ◽  
University Of Texas ◽  
Keynote Presentation ◽  
Non Hodgkin Lymphoma ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Md Anderson ◽  
The University ◽  
Washington University

In his keynote presentation, John DiPersio, MD, PhD, of Washington University, recipient of the SOHO 2020 Distinguished Lecturer Award, discussed immunotherapy for T-cell acute lymphoblastic leukemia and T-cell non-Hodgkin lymphoma. Allyson Price, MPAS, PA-C, of The University of Texas MD Anderson Cancer Center, distills the seminal research by Dr. DiPersio and discusses implications for advanced practitioners.

scholarly journals Daratumumab in Combination with Vincristine or Nelarabine As Effective Salvage Therapy for Patients with Acute Lymphoblastic Leukemia at High Risk of Relapse

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5206-5206 ◽  
Author(s):  
Yishai Ofran ◽  
Chezi Ganzel ◽  
Shimrit Harlev ◽  
Ilana Slouzkey ◽  
Ofrat Beyar Katz ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
High Risk ◽  
Salvage Therapy ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Gemtuzumab Ozogamicin ◽  
Donor Lymphocyte Infusion ◽  
High Dose ◽  
Molecular Remission

Abstract Acute lymphoblastic leukemia (ALL) relapsing after allogeneic stem cell transplantation (allo-SCT) is usually associated with poor outcome. T-ALL patients relapsing early post-allo-SCT or relapsed B-ALL patients who have failed currently available targeted and immunotherapies need an effective salvage therapy. We herein describe 3 cases where minimal residual disease (MRD) negative remission was achieved in very high-risk relapsing ALL patients with the use of daratumumab with or without nelarabine. Patient 1: A 24-year-old male diagnosed in May 2016 with T lymphoblastic lymphoma. Following ECOG 2993-based induction, his PET became negative. Additional 3 high-dose methotrexate and 3 consolidation cycles were prescribed followed by maintenance therapy. In August 2017, he relapsed in the bone marrow (BM) and central nervous system, and a second remission (CR2) was achieved after therapy with mitoxantrone + cytarabine. He underwent allo-SCT from his matched brother in CR2. Three and a half months after the transplant he experienced a third relapse. Two cycles of nelarabine were administrated followed by daratumumab 16mg/kg in a "myeloma like" protocol. BM at the end of 2 nelarabine cycles demonstrated remission but with 0.09% residual disease cells on flow cytometry. After the first 2 months of daratumumab, BM confirmed MRD eradication. One dose of 5x105/kg donor lymphocyte infusion (DLI) was also prescribed. Patient 2: A 43-year-old female diagnosed with T-ALL in February 2017. Her disease was refractory to ECOG 2993-based induction and remission was achieved only after a second-line therapy with mitoxantrone + cytarabine. She was referred to allo-SCT from her matched sister, engrafted well and developed grade 2-3 acute graft-versus-host disease which responded well to steroids. Five months post-transplant an extra-medullary relapse was diagnosed in her eye and skin, while MRD was identified in her BM. The same regimen of 2 cycles of nelarabine followed by daratumumab 16mg/kg was prescribed. Extra-medullary disease was eliminated and so was the residual BM disease. One dose of 5x105/kg DLI was also prescribed. The case of patient 3 has just been published (Ganzel C, et al. Haematologica, June 2018). In brief, this is a 21-year-old man diagnosed 7 years ago with Ph+ B-ALL. Daratumumab was prescribed to treat his 7th relapse after he had been treated with multiple TKIs, including ponatinib, underwent two allo-SCTs and received immunotherapy with 2 different anti CD19 and anti CD22 CAR-T cell agents. In parallel to daratumumab, vincristine was administered every 4 weeks as well as daily ponatinib. Molecular remission following daratumumab was confirmed by PCR for BCR/ABL. Kinetics of response and duration of follow-up: For the patient with Ph+ ALL, daratumumab was prescribed while overt disease was present in the BM but peripheral counts were low (WBC=2,000, ANC=1,000, PLT=95,000). Hematologic remission was confirmed after 1 month and molecular remission after 4 months. Unfortunately, 6 months after the first infusion of daratumumab he relapsed again and now (one year post-daratumumab administration) he is alive and treated with bortezomib and gemtuzumab ozogamicin. Both T-ALL patients achieved morphologic remission with nelarabine and received one DLI. MRD was identified in BM examination following nelarabine cycles and its elimination was confirmed in the BM at the end of the first 2 months of daratumumab (a total of 8 weekly infusions). Currently, these patients are 20 and 22 weeks following relapse and are alive and in molecular remission. In all 3 patients we noticed no significant side effects that could be related to daratumumab infusion. Peripheral WBC and PLT count dynamics are shown in figure 1. Treatment of ALL patients who relapse with high-risk features is a great challenge. Herein we report three consecutive patients who achieved MRD negativity with daratumumab. Daratumumab can be combined with other effective agents in a simple and safe protocol that may be delivered even to heavily pre-treated patients. Although larger studies with longer follow-up are required, this novel approach may offer new hope for patients with a devastating disease such as relapsed ALL. Disclosures Ofran: Novartis: Other: Served on a Novartis advisory board.

scholarly journals Intra-Tumoral Blast Heterogeneity and Implications for Minimal Residual Disease Detection in T-Cell Acute Lymphoblastic Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1076-1076
Author(s):  
Nina Friesgaard Öbro ◽  
Lars Peter Ryder ◽  
Hans Ole Madsen ◽  
Mette Klarskov Andersen ◽  
Birgitte Klug Albertsen ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cell ◽  
T Cell Receptor ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Cell Receptor ◽  
Flow Sorting ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Minimal Residual

Abstract Introduction:The early treatment response, measured as minimal residual disease (MRD), is the most important tool for treatment stratification in T-cell acute lymphoblastic leukemia (T-ALL). Flow cytometry-based MRD (Flow-MRD) monitoring, in addition to the PCR-MRD method, is often important to ensure a sensitive MRD marker. Additionally, Flow-MRD investigation may add biological information to the MRD result itself, and allow cell sorting for biological and functional analyses. Flow-MRD in T-ALL consists of identification of cells with immature T-cell phenotype in bone marrow. However, important pitfalls in Flow-MRD, e.g. treatment-related marker modulation and intra-tumoral immunophenotypic heterogeneity, are poorly described. The aim of this study was to explore the implications of these pitfalls on T-ALL MRD detection and on the concordance between the two MRD methods. Potentially both PCR- and Flow-MRD methods might miss blast subpopulations, which is important if subpopulations have divergent chemosensitivity. Methods:The patient cohort included 49 Danish T-ALL patients (1-45 years of age) treated according to the NOPHO ALL2008 protocol. Standard PCR- and flow cytometry-based MRD data were obtained as part of routine MRD monitoring. We investigated intra-tumoral heterogeneity of the leukemia-associated immunophenotype by flow cytometry (diagnostic BM samples), including clonal T-cell receptor gene-rearrangements in flow-sorted blast subpopulations (22 patients). Immunophenotypic MRD markers (including assessment of modulation) were re-evaluated at follow-up in MRD-positive patients. Flow-MRD was validated by PCR-MRD analysis in flow-sorted cell populations (61 follow-up BM samples, 32 patients). Results:At diagnosis, more than 80% of the T-ALL patients had a heterogeneous immunophenotype, most often involving CD1a, CD4, and TdT. The degree of overall heterogeneity, as defined by the number of markers with heterogeneous expression showing distinct blast subpopulations, did not show association to day29 PCR-MRD. Except for one patient, the dominant T-cell receptor clonal gene rearrangements were conserved across phenotypically diverse blasts. Immunophenotypic changes in MRD-positive patients at early follow-up often included subpopulation-loss and/or marker down-modulation of CD1a, TdT and/or CD4. The marker modulations were frequently independent of each other in different subpopulations. Overall, flow cytometry-based identification of blasts and normal cells at Flow-MRD time points was verified by PCR in the flow-sorted cells: In patients where at least 90% of the blasts showed aberrant marker expression at diagnosis, the flow-sorted MRD cells were concordantly PCR-positive, and flow-sorted phenotypically normal cells were similarly PCR-negative in all but three samples that had very high MRD levels (>20%). However, many patients had only partly-informative immunophenotypes (less than 90% of blasts having aberrant marker). Three discrepant cases with Flow-MRD underestimation showed loss of CD1a- and TdT and down-modulation of CD99, verified in flow-sorting experiments. Conclusions and Discussion: We show that intra-tumoral immunophenotypic heterogeneity—a possible result of genetic instability—is common in T-ALL patients and involves several immaturity and T-linage markers commonly used in Flow-MRD. The dominant PCR-MRD targets are in most cases conserved across the diverse blast subpopulations at diagnosis, but in rare cases PCR-MRD might miss a subpopulation. The observed immunophenotypic changes in T-ALL blasts and blast subpopulations at early follow-up, including reduction of immaturity markers, represent important pitfalls in Flow-MRD. Flow-sorting experiments verified that, when all blasts of heterogeneous immunophenotypes were informative, MRD identified by flow cytometry at follow-up was highly concordant with PCR-MRD markers in sorted cells. The T-ALL blast heterogeneity and marker modulations, which are possibly treatment protocol-specific, are important to take into account to obtain reliable Flow-MRD and thus correct treatment stratification of T-ALL patients. Disclosures No relevant conflicts of interest to declare.

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