Persistent Minimal Residual Disease Research Articles

Investigation of the immune profile of multiple myeloma patients achieving long-term survival after autologous stem cell transplantation

Objective: To identify the characteristics of the bone marrow immune microenvironment associated with long-term survival in multiple myeloma (MM) patients. Methods: In the follow-up cohort of patients with newly diagnosed MM and who received "novel agent induction therapy and subsequent autologous stem cell transplantation and immunomodulator maintenance therapy" in the First Affiliated Hospital of Sun Yat-sen University, a cross-sectional study was carried out between August 2019 and May 2020. Using NanoString technology, the RNA expression of 770 bone marrow immune-related markers was compared between 16 patients who had progression-free survival ≥5 years and 5 patients with progressive disease. Among the 16 patients who achieved long-term survival, 9 achieved persistent minimal residual disease (MRD) negative while the other 7 had persistent positive MRD. The functional scores of each kind of immune cells were calculated based on the expression level of characteristic genes, so as to indirectly obtained the proportion of each immune cell subset. The Mann-Whitney U test and the Kruskal Wallis test were used for statistical analysis. Results: The proportion of neutrophils was significantly higher in long-surviving MM patients than in patients with progressive disease [functional scores, 13.61 (13.33, 14.25) vs. 12.93 (12.58, 13.38); Z=2.31, P=0.021]. Among long-surviving patients, those who were MRD-positive had a significantly greater number of mast cells compared with those who were MRD-negative [functional scores, 7.09 (6.49, 8.57) vs. 6.03 (5.18, 6.69); H=2.18, P=0.029]. Compared with patients with progressive disease, four genes (CTSG, IFIT2, S100B, and CHIT1) were significantly downregulated and six (C4B, TNFRSF17, CD70, IRF4, C2, and GAGE1) were upregulated in long-surviving patients. Among long-surviving patients, only gene CMA1 was significantly upgraded, 10 genes (ISG15, OAS3, MX1, IFIT2, DDX58, SIGLEC1, CXCL10, IL1RN, SERPING and TNFSF10) were significantly downregulated in the MRD-positive group compared with that in the MRD-negative group, the first 5 of which are related to the interferon response pathway. Conclusions: The increased neutrophil and mast cell numbers may be related to long-term survival in MM. Interferon signaling activation may be a key bone marrow immune profiling feature for MRD-negative, long-surviving patients with MM.

Long-Term Follow-Up of Patients With Follicular Lymphoma Using Next Generation Sequencing to Detect Minimal Residual Disease

BackgroundFollicular lymphoma (FL) is a highly treatable, indolent non-Hodgkin lymphoma. Although FL is considered incurable, a patient without progression of disease by 24 months after treatment is predicted to have a survival consistent with persons without lymphoma. Using a sensitive assessment of minimal residual disease (MRD), we tested the hypothesis that MRD monitoring can predict long term remissions. MethodsUnselected patients who were in a clinical remission for at least 24 months after their last treatment were enrolled and monitored prospectively for MRD detectability using a sensitive next-generation sequencing assay (clonoSEQ, Adaptive Biotechnologies, Seattle, WA). ResultsForty-seven consecutive patients were monitored. We evaluated the MRD thresholds 10−4, 10−5, and 10−6 for the ability to predict long-term remissions in this cohort and determined that undetectable disease at 10−6 was the best predictor with a specificity and negative predictive value (NPV) of 70% and 100%, respectively. While 3 patients exhibited clinical disease progression during the course of the study, none of the 31 patients with persistent MRD undetectability at 10−6 experienced relapse. ConclusionsA significant proportion (31/47; 66.0%) of FL patients in clinical remission after ≥24 months following last therapy were undetectable at 10−6 by a sensitive assay of MRD. The threshold of sensitivity was 100%, specificity 70%, with a PPV of 19%, but a NPV of 100%. Although longer follow-up is needed for confirmation, many of these patients may continue to have durable complete remissions.

Isolation of acute myeloid leukemia blasts from blood using a microfluidic device.

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults and associated with poor prognosis. Unfortunately, most of the patients that achieve clinical complete remission after the treatment will ultimately relapse due to the persistence of minimal residual disease (MRD), that is not measurable using conventional technologies in the clinic. Microfluidics is a potential tool to improve the diagnosis by providing early detection of MRD. Herein, different designs of microfluidic devices were developed to promote lateral and vertical mixing of cells in microchannels to increase the contact area of the cells of interest with the inner surface of the device. Possible interactions between the cells and the surface were studied using fluid simulations. For the isolation of leukemic blasts, a positive selection strategy was used, targeting the cells of interest using a panel of specific biomarkers expressed in immature and aberrant blasts. Finally, once the optimisation was complete, the best conditions were used to process patient samples for downstream analysis and benchmarking, including phenotypic and genetic characterisation. The potential of these microfluidic devices to isolate and detect AML blasts may be exploited for the monitoring of AML patients at different stages of the disease.

Long-Term Results of the Dasatinib-Blinatumomab Protocol for Adult Philadelphia-Positive ALL.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.We report the long-term results of the frontline trial with dasatinib and blinatumomab in induction/consolidation (GIMEMA LAL2116, D-ALBA) for adult Philadelphia-positive ALL (Ph+ ALL), which enrolled 63 patients of all ages. At a median follow-up of 53 months, disease-free survival, overall survival, and event-free survival are 75.8%, 80.7%, and 74.6%, respectively. No events have occurred among early molecular responders. A significantly worse outcome was recorded for IKZF1plus patients. Twenty-nine patients-93.1% being in molecular response (ie, complete molecular response or positive nonquantifiable) after dasatinib/blinatumomab-never received chemotherapy/transplant and continued with a tyrosine kinase inhibitor only; 28 patients remain in long-term complete hematologic response (CHR). An allogeneic transplant was carried out in first CHR mainly in patients with persistent minimal residual disease; 83.3% of patients are in continuous CHR. The transplant-related mortality was 12.5% for patients transplanted in first CHR and 13.7% overall. Nine relapses and six deaths have occurred. ABL1 mutations were found in seven cases. The final analysis of the D-ALBA study shows that a chemotherapy-free induction/consolidation regimen on the basis of a targeted strategy (dasatinib) and immunotherapy (blinatumomab) is effective in inducing durable long-term hematologic and molecular responses in adult Ph+ ALL, paving the way for a new era in the management of these patients.

Delayed Intensification Including Venetoclax and Bortezomib Prolongs Survival in Very High Risk Acute Lymphoblastic Leukaemia

Modern multi-drug risk-stratified response-adapted chemotherapy protocols lead to >85% cure rates in childhood acute lymphoblastic leukaemia (ALL). Between 2013-2022, 707 children (0-18 years) with acute lymphoblastic leukaemia (ALL) treated systematically on the ICiCLe-ALL-14 risk-adapted protocol achieved a 3-year event-free survival (EFS) of 73% (95% confidence interval, CI 69-77). A very high risk (VHR) subgroup (N = 107) was identified with poor outcome (3-year EFS, 38% [95% CI 25-51]). This included patients with induction failure, persistent minimal residual disease (MRD) and/or select high risk cytogenetic subtypes ( BCR::ABL1 other ABL-class fusion ALL, TCF3::HLF, low hypodiploidy, IKZF1plus with high end-induction MRD, KMT2A-rearranged infant ALL). Co-culture based high-throughput drug response profiling (DRP) was performed to identify alternate chemotherapeutic drugs for these VHR patients. Primary ALL blasts extracted by density centrifugation, were seeded on immortalized human bone marrow stromal cells and treated with a 14-drug panel: prednisolone; vincristine (VCR), daunorubicin; asparaginase (ASNase), bortezomib (BZM), venetoclax (VEN), panobinostat (PNB), mitoxantrone, cyclophosphamide, cytarabine, selinexor, dasatinib, 6-thioguanine and idarubicin. Seventy-four patients (25 VHR, 37 high-risk, 7 intermediate-risk, and 5 standard-risk,) were analysed. Venetoclax, BZM and PNB were identified as active agents (IC 50 <100nM for VEN and PNB, <10nM for BZM) in 71%, 42% and 75% of VHR samples, respectively. Based on drug-sensitivity patterns of VHR ALL, a pilot study was initiated to prospectively evaluate the addition of VEN and BZM in the frontline delayed intensification (DI) phase of VHR ALL patients (N=24) after informed consent (Figure 1). Response was assessed before and after VHR-DI in 46% (11/24) patients. Good response, i.e. decrease in MRD ≥ 1 log after VHR-DI, was noted in 82% (9/11) patients. Landmark analysis comparing survival of patients (from start of DI) treated on standard DI versus VHR-DI showed significant improvement in 2-year EFS from 54% (95% CI 40-66) to 76% (95% CI 51-89) ( p=0.037, log-rank test). Overall, VHR-DI was tolerated well. No significant difference was noted in grade 4 and 5 toxicities (Common Terminology Criteria for Adverse Events v4.0) between standard DI and VHR-DI ( p= 0.053 & p=0.988 respectively, chi-square test). Fever-neutropenia and sepsis were the most frequent toxicities with VHR-DI. To identify potential mechanisms of resistance in poor-responders, transcriptome analysis was performed on diagnostic blast cells from VHR patients with good (N=5) or poor (N=5) response to VHR-DI and compared with highly sensitive SR patients (N=5). Upregulation of oxidative phosphorylation and ubiquitin-mediated proteolysis were found in good responders while non-responders showed upregulation of amino acid metabolic and RNA splicing pathways. In conclusion, drug response profiling identifies alternative combination therapies for VHR ALL. Our pilot study provides proof-of-concept of effectiveness and tolerability of inclusion of VEN and BZM in the post-induction treatment of patients with poor-response disease.

The Specific Transcriptional Signature and Clonal Selection of MGUS-like Profile Predict an Exceptionally Favorable Prognosis in Patients with Newly-Diagnosed Multiple Myeloma

Background: Achieving undetectable minimal residual disease (MRD) has been considered a functional cure in multiple myeloma (MM), emphasizing the clinical importance of depth and duration of remission. Interestingly, a subset of myeloma patients presents with an MGUS-like status, characterized by persistent M-component or detectable MRD despite systematic treatment. Surprisingly, these patients exhibit an indolent disease course and experience unexpectedly long survival (PFS ≥ 5 years). Nevertheless, the specific genomic characteristics of their tumor cells, immune microenvironment, and clonal evolution patterns are still inadequately explored. Methods: This study utilizes data from the National Longitudinal Cohort of Hematological Diseases in China (NCT04645199) to investigate the unique MGUS-like cohort. This cohort comprises patients who achieved functional cure (PFS ≥ 5 years) but retained MGUS-like features. We conducted DNA and RNA sequencing of sorted plasma cells to elucidate the specific transcriptional and genomic profiles and clonal evolution patterns, aiming to shed light on the underlying mechanisms and enable individualized treatment approaches. Results: In the study cohort, only 6.4% (35/548) exhibited the MGUS-like profile, characterized by younger age, low tumor burden, infrequent anemia and bone lesions, and stable cytogenetics. Intriguingly, the MGUS-like cohort demonstrated consistently favorable prognoses regardless of response depth, unlike classical MM patients. Analysis of the intrinsic features of tumor cells revealed a distinct transcriptome for the MGUS-like group compared to classical MM. Subsequently, we identified a MGUS-like transcriptional gene signature that effectively discriminated a rare cohort with excellent survival, irrespective of remission depth, in the MMRF database. Notably, gene set enrichment analysis (GSEA) analysis revealed the upregulation of genes involved in the adaptive immune response, T cell activation, natural killer cell-mediated immunity, and erythrocyte differentiation, along with the downregulation of genes involved in protein folding. These biological differences potentially account for the unprecedented favorable prognosis due to an activated immune microenvironment and distinct clinical features such as reduced anemia and low tumor burden. Furthermore, genomic analysis of sequential samples from MGUS-like patients demonstrated that most mutations and copy number alterations became undetectable in residual tumor cells or during relapse, suggesting clonal selection of indolent tumor clones in MGUS-like patients. Conclusions: The rare MGUS-like population exhibits unique clinical features and an exceptionally favorable prognosis with limited treatment. Utilizing the distinct tumor transcriptome and specific clonal selection pattern, early identification of MGUS-like patients could facilitate precise individualized treatment strategies.

Minimal Residual Disease (MRD) Testing By Next Generation Sequencing (NGS) after Two Cycles (CY) of Non-Intensive Chemoimmunotherapy Is Predictive of Remission Duration and Need for Maintenance Therapy (MT) in Previously Untreated Mantle Cell Lymphoma (MCL): A Wisconsin Oncology Network Study

Introduction: Despite the variable course of MCL, limited prospective markers exist to identify more indolent disease. MCL is often diagnosed in older patients (pts) less able to tolerate intensive approaches. Bendamustine/rituximab (BR) is a standard non-intensive regimen for MCL, and use of MT remains controversial. Emerging data in MCL suggest a correlation between achieving MRD negativity (MRD-) and progression-free survival (PFS). The GALLIUM study (Marcus R, et al, N Engl J Med 2017) previously showed improved PFS with a bendamustine/obinutuzumab (BO) induction compared with BR in follicular lymphoma, and we postulated this benefit may be observed in MCL. Using MRD testing, we predicted that MT may be omitted in pts achieving MRD- status after induction BO chemoimmunotherapy for MCL. Methods: Adult pts ≥18 years (yrs) with previously untreated MCL who were ineligible for more intensive therapies (including transplant) were enrolled. Pts received 4-6 CY of BO induction intravenously (IV) every 28 days (D) with B 90 mg/m2 IV D1 & 2 every 28D for 6 CY concurrent with O IV (cycle 1 = 100 mg D1, 900 mg D2, and 1000 mg D8 & 15; then 1000 mg D1, CY 2-6). Peripheral blood (PB) MRD was obtained using NGS (ClonoSEQ®) after cycle 2 BO as an exploratory endpoint. Consolidation O (CO) 1000 mg IV weekly for 4 doses was initiated ≤12 weeks after the final dose of BO. Restaging and MRD testing of PB and bone marrow aspirate (BMA) was done ≤30 days after CO completion. For pts with complete response (CR) radiographically and MRD- in PB/BMA, maintenance O (MO) was omitted. For pts without CR or persistent MRD positivity (MRD+) in the PB or BMA, MO was given with 1000 mg IV D1 of a 56-day cycle for 8 CY. Pts were followed for ≥2 years from therapy completion. The primary endpoint is PFS from D1 of BO induction. Secondary endpoints are MRD status, concordance rate of PB/BMA in predicting MRD status, response rates and overall survival (OS). Results: Twenty-one pts (of planned 32) enrolled beginning 2/2018, with follow-up through 6/1/2023. The study closed prematurely due to slow enrollment. Median age is 70 yrs with 3 pts >80 yrs; majority were men (76%). Median MIPI score is 6.11 and median ECOG performance status 0. Twenty pts (95%) have stage IV disease. Twenty pts completed 4 (n=1) or 6 CY BO. Ten pts received MO; 10 did not receive MO per protocol due to radiographic CR and MRD- PB/BMA post-CO. Six pts did not complete MO for reasons of progressive disease (n=4), infection (n=1) and new carcinoma (n=1). After cycle 2 BO, PB analysis was MRD+ in 7 pts and MRD- in 13. Concordance rates between post-CO MRD testing in PB and BMA was 70% (14/20). Of non-concordant values, all had PB MRD- but BMA MRD+. Best responses in 20 assessable pts are: CR 75% (15/20), partial response 20% (4/20), and stable disease 5% (1/20). Most common grade 3/4 toxicities were: neutropenia (10/21), leukopenia (6/21), infections (5/21) and infusion reactions (2/21). One pt had grade 5 cardiac arrest with sepsis during BO. Most common grade 3 infections were abdominal/colitis (n=3) and pneumonia (n=2). Most common grade 1/2 toxicities were nausea (14/21), diarrhea (10/21), constipation (8/21), dysgeusia (6/21), fatigue (8/21) and dry skin/rash (12/21). After a median duration of follow-up of 43.9 months (mos) (95% confidence interval [CI] 28.3-60.1), PFS at 2-yrs and 3-yrs is 66.0% (95% CI 41.6-82.2) and 58.7% (95% CI 33.2-77.3), respectively; and median PFS is 46.5 mos (95% CI 16.4-∞). MRD- status after the exploratory endpoint post-C2 BO was predictive of 2-year PFS (Figure 1a), 83.3% (95% CI 48.2-95.6) for MRD- vs. 42.9% (95% CI 9.78-73.4) for MRD+, with hazard ratio [HR] 0.34 (95% CI 0.09-1.39), p value 0.133. Evaluation of PFS by MRD status post-CO showed similar outcomes regardless of receiving MO (Figure 1b): 2-year PFS is 77.8% (95% CI 36.5-93.9) in MRD- pts post-CO vs 60.0% (95% CI 25.3-82.7) in MRD+ pts; HR 0.45 (95% CI 0.10-1.91, p value 0.278. Median OS is 46.5 mos (95% CI 35.1-∞). Conclusion: Omission of MO in pts achieving MRD- status after induction/CO did not result in worsening PFS. Observed PFS and toxicities with BO induction and CO appears comparable with other data sets utilizing a BR-based induction +/- MT in older, less fit MCL pts. Correlation between PFS and PB MRD testing after C2 induction therapy represents a potential new prognostic marker of MCL behavior, and may be an important early disease indicator in development of risk-adapted therapies.

Outcome of Infants Treated on Total Therapy for Infants with Acute Lymphoblastic Leukemia I: Results from a Non-Randomized Multi-Center Study

Infants with KMT2A rearranged (KMT2Ar) acute lymphoblastic leukemia (ALL) have a poor prognosis with an event-free-survival (EFS) of 33.6-36.9% on recent Children's Oncology Group and Interfant trials. In preclinical studies, we identified bortezomib and vorinostat as novel active agents in primary KMT2Ar infant ALL specimens that have not been included in infant regimens to date. Total therapy for infants with acute lymphoblastic leukemia I (TINI) evaluated this novel combination in a multi-institutional pilot trial for infants with de novo ALL. In this study, bortezomib and vorinostat were incorporated into an ALL chemotherapy backbone containing dexamethasone, mitoxantrone, and pegasparaginase during induction and reinduction chemotherapy cycles. A run-in dose escalation evaluated 3 dose levels of vorinostat which was then followed by a dose expansion phase. The primary endpoint of the study was tolerability; secondary endpoints included minimal residual disease (MRD), 3-year EFS and overall survival (OS). Fifty patients enrolled between 2017-2021. Median follow up was 3.4 years (range 1.6-6.8 years). The six patients in the dose escalation phase had no dose-limiting toxicities. Forty-four patients received vorinostat at the third dose level (DL3) of 180 mg/m 2/dose. 68% of patients treated at DL3 had CNS involvement at diagnosis. 68% of DL3 patients carried a KMT2Ar. The most frequent KMT2A partner genes were AFF1 (40%), MLLT1 (20%), and MLLT3 (13%). The most frequent grade 3-4 non-hematologic adverse events during induction include neutropenic fever (45%), hypertension (43%), infection (40%), anorexia (32%), diarrhea (18%) and perineal skin ulceration (16%). There were 3 episodes of sepsis and 1 induction death due to parainfluenza pneumonia. Fewer events and no deaths or proven sepsis occurred during reinduction, with only grade 3 hypertriglyceridemia exceeding 10% of patients affected (18%). 79% of all patients and 69% of KMT2Ar patients became MRD negative by flow cytometry on day 22 of induction following our investigational block. Following induction intensification with cyclophosphamide, cytarabine, and mercaptopurine, 77% and 66% of all patients and KMT2Ar patients respectively were MRD negative at the time of count recovery. Eight of the forty-four patients, all KMT2Ar, underwent stem cell transplant in first remission due to persistent MRD positivity at the end of consolidation. The 3-year EFS and OS probabilities (SE) of all forty-four DL3 patients were 56.5% (8.0) and 70.5% (7.3), respectively. The 3-year cumulative incidence of relapse (CIR) with death considered a competing event was 29.3% (6.9) and the cumulative incidence of death (CID) as a first event was 8.9% (4.5). Patients lacking a KMT2Ar had superior outcomes with 85.7% (9.4) EFS and 92.9% (6.9) OS. The EFS and OS of KMT2Ar patients were 44.8% (9.5) and 62% (9.1) respectively. CIR and CID for KMT2Ar patients was 43.5% (9.6) and 7.2% (5) respectively. KMT2Ar patients ≥90 days at diagnosis had superior outcomes compared to their younger counterparts with 59.1% (10.5) EFS and 77.3% (8.9) OS. End of induction MRD was predictive of an event in this subgroup, with 85.6% (9.4) EFS for MRD negative patients and 14.3% (13.2) EFS for MRD positive patients. In contrast, KMT2Ar patients < 90 days of age at diagnosis had poor outcomes irrespective of MRD with 12.5% (11.7) EFS and 25% (15.3) OS. Notably KMT2Ar patients < 90 days who were MRD negative at the end of induction had a median time to relapse of 600 days (range 282-969 days), a late time point for this malignancy that typically relapses within a year from initial diagnosis. This suggests the regimen effectively reduced tumor burden leading to an extended duration of remission but failed to sufficiently eradicate disease to prevent relapse. We conclude that the incorporation of bortezomib and vorinostat for treatment of infants with ALL was well tolerated. MRD responses in KMT2Ar patients were robust. Although the study was not powered to evaluate outcomes, EFS and OS in KMT2Ar patients suggest a clinical signal worth pursuing given the low proportion of patients transplanted in first remission. The successor study, TINI 2 (NCT05848687), will build upon the bortezomib/vorinostat backbone by incorporating 2 cycles of blinatumomab and the menin inhibitor ziftomenib in combination with chemotherapy during reinduction.

Blinatumomab Therapy Is Associated with Favorable Outcomes after Allogeneic Hematopoietic Cell Transplantation in Pediatric Patients with B Cell Acute Lymphoblastic Leukemia

Blinatumomab, a bispecific T cell engager that binds CD19 in leukemic cells and CD3 in cytotoxic T cells and leads to leukemic blast lysis, is often used in pediatric patients with relapsed/refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL) prior to allogeneic hematopoietic cell transplantation (allo-HCT). Concerns about the potential risk of blinatumomab-related immune-mediated toxicities after allo-HCT have not been adequately addressed. These include graft-versus-host disease (GVHD), delayed engraftment, and graft failure or rejection. Pediatric-specific data reporting post-HCT outcomes of patients treated with blinatumomab are scarce and limited to small cohorts. We sought to investigate the clinical outcomes of pediatric patients with R/R B-ALL who received blinatumomab therapy pre-HCT, focusing on overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM), as well as the incidence of immune-mediated post-HCT complications including GVHD, delayed neutrophil or platelet engraftment, graft failure, and graft rejection. We also investigated blinatumomab's effects on B cell reconstitution based on achievement of i.v. immunoglobulin (IVIG) independence post-HCT. This single-center, retrospective study included patients with B-ALL receiving blinatumomab therapy before undergoing allo-HCT, with transplantation performed between 2016 and 2021 at our institution. Patients receiving blinatumomab for relapse after allo-HCT were excluded. Patients receiving chemotherapy alone before allo-HCT during the same period composed the control group. Seventy-two patients were included, 31 of whom received blinatumomab before allo-HCT. Survival estimates were obtained using the Kaplan-Meier method, and the log-rank test was used to analyze differences between groups. Categorical variables were compared between groups using the chi-square test or Fisher exact test, and continuous variables were compared using the Wilcoxon rank-sum test. Cumulative incidences were estimated using the competing risks method, and Gray's test was used to analyze differences between groups. A Cox proportional hazards regression model was used for univariate and multivariable analyses for OS. Landmark analysis was performed at the set time points of 30 days and 100 days post-allo-HCT. Most patients in the study cohort had high-risk relapsed B-ALL. Blinatumomab therapy induced minimal residual disease (MRD)-negative remissions in all patients, whereas 5 patients (12.2%) receiving chemotherapy alone had persistent MRD pre-allo-HCT. Time from the start of therapy to the date of allo-HCT was shorter for patients who received blinatumomab compared with those who received chemotherapy (P < .0001). Blinatumomab therapy was associated with greater LFS compared to chemotherapy alone (P = .049), but when limited to 1 year, LFS was not significantly different from control (P = .066). There appeared to be higher OS, lower CIR, and lower NRM in patients receiving blinatumomab compared to the control group; however, the differences were not significant. None of the variables assessed in multivariable analysis was associated with differences in OS. When compared to the controls, blinatumomab therapy did not result in a higher incidence of acute or chronic GVHD, delayed neutrophil or platelet engraftment, or graft failure or rejection. The time to IVIG infusion independence post-allo-HCT was similar in the 2 groups. This study supports the use of blinatumomab salvage therapy for R/R B-ALL before allo-HCT given its efficacy in inducing MRD-negative remissions and optimizing LFS, as well as its lack of association with an increased incidence of post-allo-HCT adverse immune-mediated toxicities. Larger, prospective studies are needed to confirm these findings and to investigate blinatumomab's effects in long-term post-allo-HCT events.

Philadelphia Chromosome Positive and Philadelphia-Like Acute Lymphoblastic Leukemia in Children and Adolescents: Current Management, Controversies and Emerging Concepts.

Philadelphia chromosome positive (Ph+) acute lymphoblastic lymphoma (ALL) is an uncommon subtype of ALL in children, seen in 2-5% cases. Diagnostic evaluation includes conventional karyotyping and detection of BCR-ABL1 translocation by fluorescence in-situ hybridization (FISH) or reverse transcriptase polymerase chain reaction (RT-PCR). For children, the frontline management includes combination of intensive chemotherapy along with imatinib (300-340mg/m2/d) or dasatinib (60-80mg/m2/d). Imatinib/dasatinib should be introduced in induction as soon as results for BCR-ABL are available. Minimal residual disease (MRD) monitoring is essential; multi-parametric flowcytometry and immunoglobulin/T-cell receptor rearrangement PCR are the preferred methods. Intrathecal therapy with at least 12 doses of methotrexate is adequate for central nervous system (CNS) prophylaxis, but cranial radiation is necessary for CNS3 involvement. Allogeneic hematopoietic stem cell transplantation (HSCT) in first remission may be considered in high-risk cases (persistent MRD positivity/induction failure). Maintenance therapy with tyrosine kinase inhibitors (TKI) in children is debatable, with potential concerns for long term adverse effects. At relapse, the choice of TKI is guided by the presence of BCR-ABL tyrosine kinase domain resistance mutations, although the frequency of resistance mutations in children are lower. Allogeneic HSCT is essential for consolidation in second remission, if not done.Ph-like ALL is a newly recognized molecular entity, with gene expression profile similar to Ph+ALL and poor survival outcomes. In resource-constrained settings, a stepwise cost-effective diagnostic evaluation should be considered among high-risk patients without recurrent genetic abnormalities. Current treatment strategies remain similar to Ph-negative ALL. Enrolment in clinical trials is encouraged for such children to evaluate potential targeted agents in this subtype.

Hematopoietic Stem Cell Transplantation in Acute Promyelocytic Leukemia in the Era of All-Trans Retinoic Acid (ATRA) and Arsenic Trioxide (ATO).

Acute promyelocytic leukemia (APL) currently represents one of the malignant hemopathies with the best therapeutic responses, following the introduction of all-trans retinoic acid (ATRA) and subsequently of arsenic trioxide (ATO) treatment. As a result, a large proportion of patients with APL achieve long-term responses after first-line therapy, so performing a hematopoietic stem cell transplant as consolidation of first complete remission (CR) is no longer necessary. Even in the case of relapses, most patients obtain a new remission as a result of therapy with ATO and ATRA, but an effective consolidation treatment is necessary to maintain it. The experience accumulated from studies published in the last two decades shows the effectiveness of hematopoietic stem cell transplantation (HSCT) in improving the outcome of patients who achieve a new CR. Thus, the expert groups recommend transplantation as consolidation therapy in patients with a second CR, with the indication for autologous HSCT in cases with molecular CR and for allogeneic HSCT in patients with the persistence of minimal residual disease (MRD) or with early relapse. However, there is a variety of controversial aspects related to the role of HSCT in APL, ranging from the fact that outcome data are obtained almost exclusively from retrospective studies and historical analyses to questions related to the type of transplantation, the impact of minimal residual disease, conditioning regimens, or the role of other therapeutic options. All these questions justify the need for controlled prospective studies in the following years.

A long-term follow-up of observation in treatment-free remission in patients with chronic myeloid leukemia

Introduction. The option of observation without therapy with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) patients is already included in Russian and international clinical guidelines. Evaluation of long-term follow-up results of treatment free remission (TFR) in CML patients is relevant for the introduction of this approach into routine clinical practice. Aim — to demonstrate the outcomes in a long-term follow-up of CML patients who discontinued TKI therapy in the RU-SKI trial. Patients and methods. The prospective study included 98 CML patients with TKI therapy duration ≥ 3 years and a deep molecular response (DMR, BCR::ABL1 ≤ 0.01 %) duration ≥ 2 years. TKI therapy was resumed with the loss of a major MR (MMR, BCR::ABL1 &gt; 0,1 %). Results. Median time of follow-up after TKI discontinuation was 64 months (range of 51–86 months). Survival without MMR loss at 3 and 5 years after TKI discontinuation was 51 % (CI 41–61 %) and 46 % (CI 36–57 %) respectively. From 3 to 5 years of follow-up without therapy, the loss of MMR occurred in 2 (4 %) patients. There was no MMR loss observed after 5 years of follow-up. In patients with first and second treatment discontinuation, survival without MMR loss was 50 % versus 12,5 %(р = 0,039). All 50 patients with molecular relapses regained MMR and MR4 after TKI therapy resumption. BCR::ABL1 level fluctuations 0,01–0,1 % were in 62 % (n = 29) patients, who were in TFR at the time of analysis. Loss of MR4 was observed in 38 (42 %) from 90 patients with first TKI discontinuation. Survival without MMR loss from MO4 loss was 24 % at 5 years after TKI discontinuation. Loss of MO4 in the first 3 months after TKI cessation was associated with a high probability of further MMR loss (8 % versus 54 % in patients with loss of MO4 for &gt; 3 months, p = 0.00015). Conclusion. The low frequency of late relapses (4 % after 3 years of follow-up) and the possibility of long-term persistence of minimal residual disease (MRD) after discontinuation of therapy determine the need to optimize the timing of molecular monitoring, taking into account the MRD status of patients.

Treatment outcomes for acute T-lymphoblastic leukemias/lymphomas: data from the ALL-2016 multicenter prospective randomized trial

Background . The effectiveness of therapy for acute T-lymphoblastic leukemia (T-ALL) and T-lymphoblastic lymphoma (T-LBL) has significantly improved over the past decades, including through the implementation of hematopoietic stem cell transplantation (HSCT). The Russian multicenter ALL-2009 study (ClinicalTrials.gov NCT01193933) showed that performing autologous HSCT (auto-HSCT) in patients with T-ALL/LBL improves long-term results. However, the study was non-randomized and the need for auto-HSCT in clinical practice requires careful study. Aim . To assess the significance of auto-HSCT in patients with T-ALL/LBL in the framework of ALL-2016 multicenter, prospective, randomized study (ClinicalTrials.gov NCT03462095). Materials and methods . The study included 109 adult patients with T-ALL/LBL (m:f 82:27). Median age was 31 (18– 52) years. T-ALL was diagnosed in 88 (81 %) patients, T-LBL in 21 (19 %) patients. All patients are treated according to the ALL-2016 protocol. Using the web platform, upon completion of induction therapy (+70 days), all T-ALL/LBL patients who achieved clinical and hematological remission were randomized to the auto-HSCT arm or chemotherapy alone (CT). Centralized monitoring of minimal residual disease (MRD) in bone marrow samples was performed by multicolor flow cytometry at the control points according to the ALL-2016 protocol. Statistical analysis was performed using SAS 9.4. Results . 87 patients with T-ALL/LBL were randomized: 44 to the auto-HSCT arm and 43 to the CT arm. Further analysis included 25 patients who underwent auto-HSCT and 36 patients receiving only CT. Three-year relapse-free survival in T-ALL is estimated at 62 % (auto-HSCT) vs. 81 % (CT) (p = 0.3422), and in T-LBL – 67 % (auto-HSCT) vs. 79 % (CT) (p = 0.59). MRD persistence on the +70 th day of therapy according to the ALL-2016 protocol was determined in 40 % of patients (autoHSCT) and in 67 % (CT) (p = 0.057). In a multivariate analysis, it was determined that T-ALL from early T-cell precursor (ETP-variant) and MRD persistence after the end of II phase induction are the main risk factors for relapse in the treatment according to the ALL-2016 protocol. Conclusion . Performing auto-HSCT both in patients with T-ALL and T-LBL, and with MRD persistence on day +70 according to the ALL-2016 protocol did not improve long-term results. The development of new programs for the treatment of patients with MRD persistence, as well as the ETP variant of T-ALL, is of current interest.

Blinatumomab therapy for B cell acute lymphoblastic leukemia accompanied by persistent or relapsed low-level MRD prior to hematopoietic stem cell transplantation in Chinese children: a case series

BackgroundBlinatumomab could be successfully used to reduce minimal residual disease (MRD) prior to hematopoietic stem cell transplantation (HSCT) in pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL), but sound evidence is lacking in China.Case presentationThis retrospective study assessed the application of blinatumomab in B-ALL accompanied by persistent or relapsed low-level MRD before HSCT from April 2019 to July 2021. Two cases (Cases 1 and 2) initially achieved remission with MRD < 0.01% upon conventional therapy but had MRD relapse with MRD ≥ 0.01% but < 1% during maintenance treatment. Case 3 had no response to routine treatment, with high MRD (9.88% and 1.23% at days 19 and 46, respectively). Nevertheless, all patients had undetectable MRD. Cases 2 and 3 had undetectable fusion gene following blinatumomab therapy. By bone marrow monitoring (bone marrow morphology, bone marrow MRD and fusion gene) post-HSCT, the patients were persistently negative until May 15, 2022. No patient had serious adverse events before or during blinatumomab treatment.ConclusionsBlinatumomab therapy showed a good performance for three pediatric cases with detectable but low MRD before HSCT in China. However, further prospective studies with large sample sizes are still needed for further clarification.

Optimal approach to T-cell ALL.

T-lineage acute lymphoblastic leukemia (T-ALL) is curable for most children and adolescent and young adult patients with contemporary frontline chemotherapy regimens. During the past decade, improved survival rates have resulted from the optimization of frontline chemotherapy regimens, the use of minimal residual disease (MRD) assessment for evaluating a patient's risk for relapse, and the intensification of treatment based on the persistence of MRD. Optimization of initial therapy is critical because relapsed T-ALL after initial intensive chemotherapy is incurable for most adult patients. Current T-ALL salvage chemotherapy regimens are minimally effective, and unlike in B-cell ALL, there are no approved antibody therapies or chimeric antigen receptor T-cell therapies for relapsed disease. Immunotherapy and small-molecule inhibitors are beginning to be tested in relapsed T-ALL and have the potential to advance the treatment. Until effective salvage strategies are discovered, however, intensive frontline therapy is required for cure. In this article I review the current frontline chemotherapy regimens for adult patients with T-ALL, summarize the novel targeted and immune therapeutics currently in early-phase clinical trials, and outline how these therapies are helping to define an optimal approach for T-ALL.

Gimema ALL2418: Interim Analysis of a Phase Iia Study of Feasibility and Effectiveness of Inotuzumab Ozogamicin in Adult Patients with B-Cell Acute Lymphoblastic Leukemia with Positive Minimal Residual Disease before Any Hematopoietic Stem Cell Transplantation

Background: Persistence of minimal residual disease (MRD) is associated with a high rate of treatment failure, relapse, and death in B-cell acute lymphoblastic leukemia (B-ALL). Particularly, patients who remain MRD positive before an allogeneic hematopoietic stem cell transplant (HSCT) have an expected disease-related death rate due to the disease of about 60%. The T cell-engager CD19-directed therapy blinatumomab demonstrated considerable efficacy in this setting, however resistant or unsuitable patients have no alternative therapy. Inotuzumab Ozogamicin (IO) is a CD22-directed antibody-drug conjugate with remarkable efficacy in B-ALL with overt disease. Furthermore, IO does not need a high effective immune system to exert activity. Methods: In this multicenter phase 2 trial (NCT03610438), we are investigating the efficacy of IO in obtaining MRD negativity in two cohorts of 38 Ph+ and 38 Ph- B-ALL patients. IO was administered at the dose of 0.5 mg/sqm on days 1, 8, and 15 of a 28-days cycle. Patients who did not obtain MRD negativity after the 1st IO cycle had the option to receive the 2nd IO cycle maintaining the same dosage. Responding Ph- patients received short-term maintenance with low-dose chemotherapy (alternating vincristine, cyclophosphamide, prednisone, methotrexate, and 6-mercaptopurine), responding PH+ patients received tyrosine kinase inhibitor (TKI) for up to 12 weeks, allowing proper IO washout before HSCT. HSCT ineligible patients entered into low-dose chemotherapy or TKI maintenance for up to 2 years. For the primary endpoint, MRD was centrally assessed at baseline, after course 1, after course 2, and eventually before transplant with high sensitive molecular methods for BCR-ABL1 or V(d)J fusion transcripts. Here, we present the results of an unplanned interim analysis that was generated to evaluate the continuation of the study considering the slow accrual due to the Sars-COV2 pandemic. Results: To date, 51 patients underwent screening procedures, and 43 were considered eligible. We report data from the first 39 patients treated in the study. Nineteen out of 39 patients had Ph- B-ALL and 20/39 Ph+ B-ALL. Eighteen out of 39 (46%) patients were male. The median age was 55 years (22-84), 15/39 patients (38%) were older than 65 years. Demographics were comparable between Ph+ and Ph- patients. Within Ph+, ALL 39% of patients harbored p190 and 61% p210 fusion transcript. Within Ph- B-ALL, 1 patient harbored ALL1/AF4 and 1 patient harbored ALL1/ENL fusion transcript. Most of the patients received 1 (16/39, 42%) or 2 (19/39, 50%) previous lines of therapy; 5 patients (13%) were resistant to blinatumomab, and all of them had Ph- B-ALL. Twelve out of 19 (63%) Ph- B-ALL patients received only 1 IO cycle, 7/19 (37%) received 2 cycles; 5/20(25%) Ph+ B-ALL received only 1 IO cycle, and 15/20 (75%) received 2 cycles. To date, central MRD monitoring is available for 20 patients (12 Ph- and 8 Ph+ B-ALL, ongoing for the remaining cases). Overall, MRD negativity was obtained in 7/20 patients (35%); Particularly, in Ph- B-ALL cohort 5/12 (42%) patients achieved MRD negativity, 4/12 (38%) achieved disease reduction at low level MRD positivity (<10-4); in Ph+ B-ALL cohort, 2/8 (25%) patients achieved MRD negativity. One out of 5 (20%) blinatumomab pre-treated patients obtained MRD negative response. IO was an effective bridge to HSCT for 10/39 patients (26%; in patients <65 years old, 9/24 patients, 37%); Specifically, all 7 patients who obtained MRD negativity after IO, a patient with low-positive MRD and 2 patients with non yet available MRD data were bridged to HSCT. Accordingly, with the caveat of a short median follow-up (2.8 months, range 0.6-20.0 months), overall survival in the study population seems promising (figure 1, median OS not reached). Overall, adverse events collected during the study were limited in number and grading. Also, myelotoxicity was manageable. Out of 39 patients, we documented 1 veno-occlusive disease (2.5%) that occurred within 20 days from the last IO dose and before any HSCT. Conclusions: IO administration demonstrated activity with a good safety profile in the setting of MRD positive B-ALL, including blinatumomab resistant patients. Importantly, IO was capable to bridge 37% of eligible patients to HSCT, augmenting the chance to achieve a cure. The continuation of the study will deliver mature efficacy and survival data for a proper evaluation of this promising strategy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Epigenetic Fine Mapping and Functional Dissection of Inherited Non-Coding Variation Impacting the Pharmacogenomics of Acute Lymphoblastic Leukemia Treatment

Acute lymphoblastic leukemia (ALL) is the most prevalent childhood cancer. Despite cure rates exceeding 90%, relapsed ALL is the 5th most common pediatric cancer. Although chemotherapeutic drug resistance remains the primary cause of treatment failure and relapse, it remains unclear to what extent non-coding inherited DNA sequence variants impact gene regulatory programs that contribute to differences in chemotherapeutic drug resistance and clinical outcome in childhood ALL. To address this knowledge gap we performed epigenetic fine mapping on inherited non-coding DNA sequence variants associated with ex vivo resistance to six antileukemic agents (dexamethasone, prednisolone, l-asparaginase, vincristine, 6-mercaptopurine and 6-thioguanine) in primary ALL cells from pediatric patients and inherited non-coding DNA sequence variants associated with clinical outcome (persistence of minimal residual disease and relapse) in pediatric patient cohorts using chromatin accessibility data from over 130 primary ALL cells, ALL cell lines and ALL xenografts. This analysis fine mapped over 1700 variants (sentinel variants and variants in high linkage disequilibrium; r2>0.8) to cis-regulatory elements in the ALL genome. To comprehensively dissect the functional effects of these fine mapped variants on gene regulatory activity we performed massively parallel reporter assays (MPRAs) in 10 human ALL cell lines of both B- and T-cell lineages. MPRAs utilized 23 DNA barcodes per variant allele and tested variants at bidirectional promoters using both sequence orientations. In total, 98,168 oligonucleotides each containing 175-bp of genomic sequence centered on each variant allele and a unique 10-bp barcode sequence were evaluated for gene regulatory activity. MPRA identified 558 variants with significant and concordant allele-specific activities in three or more ALL cell lines. Expression quantitative trait loci (eQTL) mapping and HiChIP three-dimensional promoter loop profiling identified candidate target genes for a subset of functional variants. We additionally evaluated the functional effects of top ranked variants using luciferase reporter assays and CRISPR/Cas9 genome editing. These variants were associated with the expression of B3GNT5, CACUL1, HERC1, KDM4C and VRK3. Notably, two of these functional variants (rs10411204 and rs1247117) impacted transcription factor (TF) consensus DNA motifs for AP-1 family TFs and PU.1. Collectively, these data suggest that many inherited non-coding variants associated with pharmacogenomic traits in childhood ALL have significant gene regulatory effects. Importantly, the identification of chemotherapeutic drug resistance-associated molecular pathways perturbed by inherited non-coding variants can improve our ability to circumvent drug resistance with novel therapeutic approaches.

Clinical Impact of Next Generation Flow in Bone Marrow Vs Qip-Mass Spectrometry in Peripheral Blood to Assess Minimal Residual Disease in Newly Diagnosed Multiple Myeloma Patients Receiving Maintenance As Part of the GEM2014MAIN Trial

Introduction: GEM2014MAIN is a phase 3, multicenter, open-label, randomized trial exploring maintenance treatment with lenalidomide and dexamethasone (Rd) vs lenalidomide, dexamethasone and ixazomib (IRd) after autologous stem cell transplantation in newly diagnosed patients with multiple myeloma (MM). The study includes yearly analysis of minimal residual disease (MRD) in bone marrow (BM) by Next Generation Flow (NGF) and the results at year 2 guide further management. Mass spectrometry methods measuring low-level immunoglobulins have shown potential for peripheral-blood (PB) based MRD assessment in MM. Aim: In this study, we analyzed and compared the results and clinical impact of MRD evaluation in BM by NGF and in PB by quantitative immunoprecipitation mass-spectrometry (QIP-MS) during maintenance in patients enrolled in the GEM2014MAIN trial. Patients and Methods: Patients achieving at least stable disease at the end of the GEM2012MENOS65 trial were included in the GEM14MAIN, and randomized to receive Rd (lenalidomide 15mg po od days 1-21 and dexamethasone 20mg po od days 1-4 and 9-12) or IRd (Rd plus ixazomib 4mg po od days 1, 8 and 15) in cycles of 28 days. After two years of treatment, BM samples were analyzed by NGF (sensitivity of 3x10-6) as per protocol: if MRD was undetectable, maintenance was discontinued; if detectable, Rd with reduced dexamethasone at 20mg po od only days 1-4 was continued for 3 additional years. At the same time point, MRD was assessed in PB by QIP-MS with anti IgG/A/M, total k and total l beads using the EXENT system (The Binding Site, in development). The association of MRD detection by either method with progression-free survival (PFS) was assessed by the Kaplan-Meier method. Landmark analyses of PFS at 2 years post-maintenance were performed to minimize lead-time bias. Additional survival analyses were carried out to evaluate the clinical impact of MRD evolution during the study period. Results: 156 patients with paired BM/PB samples available after 2 years of maintenance were included in the analysis. NGF detected residual disease in 29% (45/156) of cases and EXENT in 24% (37/156). The results of both techniques were concordant in 85% of cases and discordances were due to 16 patients (10%) NGF+/EXENT- and 8 (5%) NGF-/EXENT+. Of note, 8/16 cases NGF+/EXENT- corresponded to light-chain MM (anti-free light chain beads were not used in this study). Therefore, overall, and considering NGF as a reference, the negative predictive value (NPV) of EXENT was 87% and the positive predictive value (PPV) of 78% (p<0.0001). With a median follow-up of 66 months from the start of the GEM14MAIN, MRD detection by either method associated with a shorter PFS at 5 years as compared to patients with undetectable MRD: NGF: 57% vs 89%, respectively; HR= 6.54 (2.92-14.67); p<0.0001; EXENT: 62%% vs 86%, respectively; HR= 4.79 (1.99-11.53); p=0.0005. We also analyzed the evolution of MRD between enrollment and after 2 years of maintenance, since we already had MRD results by both methods at the end of the GEM2012. Patients were grouped into 1) those with persistent MRD positivity at the two time points or converting from MRD- to + by either method and 2) those with sustained MRD negativity at the two time points or converting from MRD+ to - by either method. Both NGF and EXENT showed that persistent MRD+ or conversion from MRD- to MRD+ were associated with a shorter PFS at 66 months, compared to patients who remained MRD- or converted from MRD+ to MRD-: NGF: 54% vs 89%, respectively; HR = 8.9 (3.55-22.08); p <0.0001; EXENT: 61% vs 86%, respectively; HR: 4.95 (1.91-12.9); p=0.0010. Conclusions: Our study shows that, during maintenance, the identification of MRD by NGF and EXENT and its evolutionary pattern are both associated with a comparable clinical value in terms of PFS. Supported by a NPV of 87% as compared to NGF, mass spectrometry could be used to define the optimal time-point for BM-based MRD assessments as well as, alongside with standard methods, to introduce MRD adapted treatment approaches.

Interferon-α-2b As a Maintenance Therapy Gain a High Rate of MRD Negative Conversion and Improve RFS in Patients with Favorable-Risk Acute Myeloid Leukemia----a Prospective, Single-Arm Study

Background: Maintenance therapy in favorable-risk is still controversial, so the maintenance therapy of AML is of great concern. Interferon-α (IFN-α), a type Ⅰ IFN, is a well-known antitumor agent, which has an immunoregulatory function. Several studies have shown that IFN has a definite therapeutic effect on AML. Indeed, studies have reported that IFN-α as maintenance therapy in patients with AML can prevent leukemic relapse. However, the only randomized controlled trial (RCT) that explored the role of IFN-α as maintenance therapy in AML found no difference between the comparison groups in remission duration, overall survival (OS), disease-free survival (DFS) or relapse-free survival (RFS). In our previous respective studies, IFN-α-2b as a maintenance therapy may reduce the relapse rate in patients with favorable-risk AML after consolidation chemotherapy. Moreover, IFN-α-2b could effectively control minimal residual disease (MRD) in acute leukemia/myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation (HSCT). The aim of this study was to evaluate the efficacy and safety of IFN-α-2b in the maintenance of favorable-risk AML. Method: This is an interim analysis of an ongoing clinical prospective study (trial registration number: ChiCTR2000035310) of a planned 31 favorable-risk (NCCN Guideline) AML patients with MRD positive who underwent 1-2 therapeutic induction chemotherapy for complete hematologic remission (CR) and completed 4-6 courses of consolidation chemotherapy. MRD positive was defined as detectable MFC-MRD >0.1% or fusion genes level decreased by >3 log. 22 patients were recruited in our study to date. Patients were administered with 3 million U of IFN-α-2b three times a week for 18 months. Bone marrow assessments were performed on the 2nd, 5th, 8th, 11st, 14th, 18th month since IFN-α-2b therapy. The primary objective is to determine the cumulative rates of MRD negative conversion, 3-year RFS and adverse reactions. Results: Patients were classified as favorable-risk category according to cytogenetics and molecular biology. 22 participants with favorable-risk AML were enrolled in this study, and 2 of them received IFN-α-2b less than 3 months, who were not evaluated in this report. The molecular biological characteristics of this study were AML-ETO+/c-KIT- 11 cases; AML-ETO+/c-KIT+ 2 cases (T417_D419delinsIP); CBFβ-MYH11+/C-KIT- 5 cases; CBFβ-MYH11+/C-KIT+ 2 cases (Y418_D419insFF, D816Y); NPM1+/FLT3-ITD- 3 cases; and CEBPA double mutation 1 case. The median age of the 22 participants was 47.5 (18.0-66.0) years old. Outcome data were updated as of July 2022, for a median follow-up 13.5 (6.6-24.0) months of the 20 patients received IFN-α-2b more than 3 months, and the median duration of treatment was 13.5 (5.2-18.0) months. Among 20 evaluated patients, the cumulative rates of MRD negative conversion is 66.7±11.0% after the median time of 4.4 (1.1-8.1) months IFN-α-2b treatment (Figure 1). As for recurrence, 2 patients had hematologic recurrence, with the estimated rate of 2-year RFS was 86.1±9.4% (Figure 2). Meanwhile, there are 5 persistent MRD positive participants, 3 of them got decreased MRD level for 1 log-fold, 1 case got increased MRD level for 2 log-fold, and MRD level did not decline in 1 case. The regimen was well tolerated. In terms of safety, the most frequent nonhematologic adverse events were fever (11/20, 55.0%) after IFN-α-2b therapy. 4/20 (20.0%) developed hematologic toxicity which were thrombocytopenia, 1/20 (5.0%) had muscle pain, 1/20 (5.0%) elevated hepatic transaminases, 1/20 (5.0%) developed rash. Conclusion: IFN-α-2b as maintenance therapy for CR1 patients with favorable-risk AML gain a high rate of MRD negative conversion and high rate of 2-year RFS Interferon therapy is safe and well-tolerated. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Fixed-Duration Immunochemotherapy Approach Combined with Ibrutinib in CLL Produces Deep and Sustained MRD Responses: 5.5-Year Results from the Icll-07 Filo Trial

Introduction In previously untreated, medically fit patients with chronic lymphocytic leukemia (CLL), the availability of targeted agents has led to research interest in achieving deep, durable remissions and improving survival outcomes. The phase II ICLL-07 (NCT02666898) trial by the French Innovative Leukemia Organization (FILO) evaluated a fixed-duration (15-month) immunochemotherapy approach (no more than 4 fludarabine/cyclophosphamide [FC]-obinutuzumab cycles). Primary analysis showed the approach was safe and 62.2% (84/135) of all patients enrolled achieved complete response (CR) with bone marrow (BM) minimal residual disease (MRD) <0.01% (Michallet et al Lancet Haematol 2019;6:e470-9). Follow-up at median 37 months from treatment start showed a persistent MRD benefit beyond end of treatment, high survival rates, and low long-term toxicity (Michallet et al Blood 2021;137:1019-23). Here we report long-term results at median 64 months from treatment start (data cut-off 20 May 2022). Methods Between 27 October 2015 and 16 May 2017, 135 previously untreated, medically fit patients with CLL were enrolled from 27 FILO centers. All received obinutuzumab 1000 mg (8 infusions over 6 cycles) plus ibrutinib (420 mg/day for 9 months). Following evaluation at D1 M9 (N=130 evaluable), those in CR with BM MRD <0.01% then continued only ibrutinib 420 mg/day for 6 additional months (I arm; n=10); otherwise, patients received 4 cycles of FC-obinutuzumab 1000 mg alongside continuing ibrutinib 420 mg/day for 6 additional months (I-FCG arm; n=115). Beyond end of treatment, patients were followed for peripheral blood (PB) MRD every 6 months, response every 3 months, progression-free/overall survival (PFS/OS), and safety. MRD was assessed by 8-color flow cytometry, using a highly sensitive (10-6) technique developed by the FILO group that enables subdivision of classical MRD <0.01% into low-level positive MRD <0.01% and undetectable MRD. Results At D1 M16, undetectable PB MRD rates were 80.0% (8/10) in the I arm and 92.5% (99/107) in the I-FCG arm. Beyond end of treatment, in the I arm the undetectable PB MRD rate decreased rapidly, and by M40 all patients had PB MRD positivity (≥0.01% or low-level positive <0.01%). In the I-FCG arm, the undetectable PB MRD rate was 76.3% (61/80) at M40, and of patients currently investigated at M64, 50/62 (80%) still had undetectable PB MRD (Figure 1). Four relapses occurred beyond end of treatment, including 2 CLL progressions (both Richter's syndrome). Throughout follow-up, no differences in undetectable PB MRD rates were apparent in the I-FCG arm according to the IGHV -mutated versus unmutated status (currently at M64: 20/27 versus 25/35, P=0.26). Overall 4-year PFS and OS rates (95% confidence intervals) were 95.5% (92% to 99 %) and 96.2% (93% to 99.5%), respectively. Of 12 deaths overall, 7 occurred beyond end of treatment, with 5 since last publication due to Richter's syndrome at M50, COVID at M50, lung cancer at M50, myelodysplastic syndrome at M60, and acute myeloid leukemia at M69. Other serious adverse events since last publication were metastatic prostate adenocarcinoma at M50 and suspicion of cerebrovascular accident at M65. Conclusion Long-term results from the ICLL-07 trial in previously untreated, medically fit patients with CLL demonstrated that that our fixed-duration (15-month) immunochemotherapy approach produced deep and sustained undetectable PB MRD responses that were correlated to PFS, without excess toxicity. These long-term MRD results remain the best to date even compared to the new targeted therapy combinations ie ibrutinib +veneteclax or obinutuzumab + venetoclax A randomized trial is needed to compare our approach with a chemotherapy-free strategy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal