Minimal Residual Disease Negative Status Research Articles

Abstract 5071: Minimal residual disease (MRD) status by peripheral blood mononuclear cells (PBMCs) and circulating tumor DNA (ctDNA) demonstrates rapid, deep, and sustained response in patients (Pts) with relapsed/refractory follicular lymphoma (R/R FL) treated with subcutaneous (SC) epcoritamab monotherapy in the pivotal phase 1/2 EPCORE™ NHL-1 trial

Abstract Introduction: Outcomes in high-risk R/R FL are poor. Epcoritamab SC, a CD3xCD20 bispecific antibody, demonstrated promising efficacy with a manageable safety profile in pts with R/R FL after ≥2 prior lines of therapy (phase 1/2 EPCORE NHL-1; NCT03625037). Here we evaluated MRD with PBMCs and ctDNA in pts with R/R FL and correlated the results with clinical findings. Methods: Adults with R/R FL 1-3A enrolled in EPCORE NHL-1 received epcoritamab SC in 28-day cycles. MRD analysis was performed on longitudinal plasma and PBMC samples collected at prespecified timepoints (clonoSEQ assay, Adaptive Biotechnologies). Screening tumor biopsies were used to identify trackable tumor clones; samples were quantified as tumor clones detected per mL plasma for ctDNA and per one million nucleated cells for PBMC. Overall response and progression-free survival (PFS) were assessed using Lugano criteria by independent review committee. Results: Of 128 pts in the R/R FL 1-3A cohort, 91 with PBMC data and 100 with ctDNA data were MRD evaluable. Overall MRD negativity was achieved in 67.0% [95% CI: 56.4-76.5] of pts per PBMC and 68.0% [95% CI: 57.9-77.0] of pts per ctDNA. Concordance of subject-level MRD status was high (79 of 89 with PBMC and ctDNA data; 88.8%). In most pts, MRD negativity was reached prior to radiographic complete response (PBMC, 76.4%; ctDNA 58.5%). MRD negativity by PBMC preceded ctDNA (median days to MRD negativity, 28 [PBMC] vs 57 [ctDNA]), suggesting a difference in methodology in detecting tumor DNA. Pts who became MRD negative had prolonged PFS (median not reached). Baseline MRD levels were not associated with clinical outcomes (PBMC; Wilcoxon P=0.59, ctDNA P=0.39). PFS was similar in pts achieving MRD negative status (median not reached, PBMC and ctDNA), independent of high-risk/difficult-to-treat disease (≥4 prior lines, Ann Arbor stage III-IV, bulky disease, double refractory, FLIPI 3-5, and POD24). The overall MRD negativity rate was also similar in high-risk pts, except those with ≥4 prior lines of therapy. Conclusions: Based on the EPCORE-NHL-1 study, one of the first pivotal studies to report MRD in pts with R/R FL, epcoritamab drives rapid, deep, and sustained responses as supported by MRD assessment by both PBMC and ctDNA. MRD results correlate with clinical outcome, and achieving MRD negativity is associated with longer PFS. PFS was similar among all pts who achieved MRD negativity, including those with high-risk disease. Citation Format: David Soong, Işıl Altıntaş, John Karavitis, Kim M. Linton, Wojciech Jurczak, Catherine Thieblemont, Kevin Zhao, Edith Szafer-Glusman, Daniela Hoehn, Elena Favaro, Mariana Sacchi, Maria Jure-Kunkel. Minimal residual disease (MRD) status by peripheral blood mononuclear cells (PBMCs) and circulating tumor DNA (ctDNA) demonstrates rapid, deep, and sustained response in patients (Pts) with relapsed/refractory follicular lymphoma (R/R FL) treated with subcutaneous (SC) epcoritamab monotherapy in the pivotal phase 1/2 EPCORE™ NHL-1 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5071.

A phase II trial of TAS-102 in patients with colorectal cancer with ctDNA-defined minimal residual disease post-adjuvant therapy: Results from the MD Anderson INTERCEPT Program.

136 Background: Circulating tumor DNA (ctDNA) has emerged as a novel marker with high specificity and positive predictive value for identifying radiographically occult microscopic or minimal residual disease (MRD) in colorectal cancer (CRC) patients (pts). An additional widely acknowledged unmet need is the development of therapeutic strategies to eradicate MRD and increase the cure rate of the disease. Ongoing trials are evaluating MRD as a biomarker for determining the intensity of post-operative adjuvant therapy. However, the feasibility and efficacy of therapy in pts who are MRD+ during surveillance (after all curative intent treatments including adjuvant chemotherapy) is unknown. Methods: In this proof-of-concept phase II study, pts with stages II-IV CRC noted to be MRD+ during surveillance (ctDNA+ but no radiographic evidence of disease on imaging in last 30 days) received 6 months (m) of TAS-102. Pts were identified through the MD Anderson INTERCEPT program that integrates MRD testing with a tissue informed assay (Signatera) into standard of care for CRC pts. The primary endpoint was 6-m ctDNA clearance and secondary objectives included 3-m ctDNA clearance, and disease-free survival (DFS). Assuming H0 = 5% spontaneous, HA = 30% ctDNA clearance with TAS 102 & 1-sided α = 0.05, 15 patients are required for β = 85%. Results: Between 7/22/22 and 9/7/23,15 pts with MRD were enrolled. Baseline characteristics included a median age of 62 years (range: 37-73), Caucasian (77%), male (77%), resected Stage IV (92%) and median ctDNA level of 1.55 MTM/ml (range 0.04-28.72). At data cutoff, 11 pts had 3-m ctDNA levels and 10 had a decrease in their ctDNA level (91%) including 5 with undetectable levels (45%). At 6-m, 60% of patients had ctDNA levels at or below prior levels; three maintained undetectable ctDNA at 6-m: of those, two pts had subsequent radiographic progression following therapy completion. Median DFS was 9.4-m in the full cohort. Conclusions: We demonstrate the feasibility of identifying and enrolling MRD+ pts through screening during surveillance onto therapeutic trials and show the ability of an experimental therapy to convert patients to MRD negative status, a necessary but not sufficient step for disease eradication. Preliminary results suggest that treatment with TAS-102 is effective in inducing ctDNA clearance in the short term in most pts, but with no evidence of persistent clearance. Updated results including 6-m ctDNA levels and survival data will be presented. Clinical trial information: NCT05343013 .

Blood Product Utilization Among Adolescent and Young Adult Patients with Acute Lymphoblastic Leukemia: A Single Center Ex

Background: Adolescent and young adult (AYA, 15-39 years old) patients with acute lymphoblastic leukemia (ALL) often experience pancytopenia and severe immunosuppression. Particularly during intensive phases of chemotherapy, allogeneic blood transfusion support is essential in their care. The utilization of both red blood cell (RBC) and platelet transfusions, as well as the thresholds used to determine when transfusions are needed, are poorly described in this population. The objective of this study is to describe blood product utilization in AYA patients with ALL treated at our institution.
 Methods: A cohort of 20 AYA patients with ALL treated at Riley Hospital for Children from October 2020 to July 2023 were identified for data collection. Pre- and post-transfusion laboratory values, transfusion totals, comorbid events or complications, transfusion reactions, and minimal residual disease (MRD) values were collected and analyzed. All values reported are mean ± standard deviation for continuous variables and n (%) for categorical variables. Values were calculated individually for each patient for each phase of therapy and averaged across all patients.
 Results: Patients studied had varying needs for transfusions throughout their therapy (50.75 ± 48.06), with an average of 22.95 ± 15.65 RBC transfusions and 25.60 ± 29.65 platelet transfusions. Patients being treated with standard chemotherapy protocols required moretransfusions during induction (14.13 ± 21.56) and delayed intensification (14.07 ± 24.29) phases compared to other phases. Patients with MRD positive status required more transfusions (69.14 ± 58.14) than patients with MRD negative status (40.92 ± 40.84).
 Conclusions and Potential Impacts: This study helped to elucidate the need for transfusions among the AYA ALL patient population, throughout the different phases of treatment. These findings hold implications for establishing guidelines that could clarify when transfusions should be given in this population, helping physicians provide the best care to future patients.

Intensified conditioning regimens with total marrow irradiation/etoposide/cyclophosphamide and busulfan/etoposide/cyclophosphamide overcome the impact of pre-transplant minimal residual disease on outcomes in high-risk acute lymphoblastic leukemia patients in complete remission.

Among high-risk acute lymphoblastic leukemia (ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), those with positive minimal residual disease (MRD) are susceptible to poor outcomes. Therefore, it is necessary to determine the most suitable preparatory regimen for these patients. Data were analyzed from 141 patients who received allo-HSCT and were diagnosed with high-risk ALL. These patients underwent intensified conditioning regimens, including either total marrow and lymphoid irradiation (TMLI)-etoposide (VP16)-cyclophosphamide (CY) or busulfan (BU)-VP16-CY between October 2016 and November 2022. A total of 141 individuals were in complete remission (CR) before transplantation and, among all patients, 90 individuals exhibited a negative MRD status and 51 patients had a positive MRD status. In patients who tested negative for MRD, the incidence of relapse within a 2-year timeframe was 25.0% (24.8%-25.5%), compared with 32.2% (31.2%-33.2%) in MRD-positive patients; however, this difference was not statistically significant. There were no significant differences in the 2-year disease-free survival (DFS) and 2-year overall survival (OS) rates between the MRD-negative and MRD-positive groups (DFS: 67.2% (57.9%-78.1%) vs. 55.5% (42.6%-72.3%); OS: 69.0% (61.9%-88.2%) vs. 66.7% (53.9%-82.5%)). Furthermore, no notable variations were observed in the occurrence of transplant-related mortality (TRM) and graft-versus-host disease (GVHD) across the two groups. This study reveals the benefits of TMLI-VP16-CY and BU-VP16-CY conditioning regimens in high-risk ALL patients with CR and MRD-positive status. A large-scale prospective clinical trial is warranted in the future.

Isatuximab in the treatment of refractory and relapsed multiple myeloma: literature review and case report

Multiple myeloma is a malignant tumor characterized by the proliferation of clonal plasma cells and currently remains an incurable disease, despite advances in therapy. Resistance and development of double refractoriness represent a significant problem, worsening the prognosis. To overcome double refractoriness, new proteasome inhibitors carfilzomib and ixazomib, the 3rd generation immunomodulator pomalidomide and monoclonal antibodies daratumumab, elotuzumab and isatuximab are used. Based on randomized phase III ICARIA-MM and IKEMA studies results, which demonstrated, along with a manageable safety profile, advantages in increasing the antitumor response depth, the rate of achieving negative minimal residual disease status and survival in all subgroups of patients with refractory/relapsed multiple myeloma, isatuximab is used in IsaPd (isatuximab, pomalidomide, dexamethasone) and IsaKd (isatuximab, carfilzomib, dexamethasone) combination. This article discusses the clinical pharmacology of isatuximab. The results of studies demonstrating the effectiveness and safety of antitumor therapy regimens including isatuximab, which made it possible to use it in clinical practice, are presented. We present a case report of a patient with refractory/relapsed multiple myeloma who received 3 lines of antitumor treatment, including class 2 proteasome inhibitors, lenalidomide and the monoclonal antibody elotuzumab. After 3 cycles of IsaPd (8 injections of isatuximab), partial remission and pain relief were recorded. The achieved antitumor effect, along with the absence of significant adverse events, facilitated the continuation of therapy at recommended doses.

Prophylactic or Preemptive Donor-Derived CD19 CAR-T Cell Infusion for Preventing Relapse in High-Risk B-ALL after Allogeneic Hematopoietic Stem Cell Transplantation

Introduction: Relapse remains a significant challenge in the management of high-risk B-cell acute lymphoblastic leukemia (B-ALL) patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Existing post-transplant relapse prevention strategies for high-risk B-ALL patients after transplantation, particularly in cases of Philadelphia chromosome-negative B-ALL, have limitations and suboptimal efficacy. This study aims to evaluate the efficacy and safety profile of prophylactic or preemptive infusion of donor-derived CD19 chimeric antigen receptor T (CAR-T) cells in high-risk B-ALL patients after allo-HSCT. Methods: Between May 2017 and July 2022, high-risk B-ALL patients with minimal residual disease (MRD) positive or MRD negative status after allo-HSCT were enrolled in clinical trials of donor-derived CD19 CAR-T cell therapy (ChiCTR 2000041025 and ChiCTR-ONN-16009862). The primary outcome was the cumulative incidence of relapse (CIR). Secondary outcomes were progression-free survival (PFS), overall survival (OS) and CAR-T cell treatment-related toxicities. Results: A total of 25 high-risk B-ALL patients who received infusion of donor-derived CD19 CAR-T cells after allo-HSCT were enrolled in the CAR-T cell group, including 8 patients with MRD and 17 patients without MRD. A contemporaneous cohort of 43 high-risk B-ALL patients who did not receive CAR-T cell therapy in MRD-positive or MRD-negative status after transplantation was also included as a control group. The median age of patients enrolled in the CAR-T group was 29 years (range: 9-60 years). The median infused CAR-T cell dose was 2.5×10^6/kg (range: 1.0-5.0×10^6/kg), with a median time from transplantation to CAR-T cell treatment of 122 days (range: 45-315 days). The median follow-up duration was 23.6 months (range: 8.3-60.6 months). Of the 25 patients in CAR-T group, eight MRD-positive patients achieved MRD-negative remission after CAR-T cells treatment (Figure1A). The two-year cumulative incidence of relapse in the CAR-T cell group was significantly lower at 4.8% (95% CI: 0.0%-12.6%) compared to the control group's incidence of 26.6% (95% CI: 11.4%-41.8%, P = 0.03，Figure1B). Additionally, the CAR-T cell group exhibited a higher two-year PFS rate [86.3% (95% CI: 71.8%-100%)] compared to the control group [63.5% (95% CI: 48.0%-79.0%), P = 0.04]. However, the two-year OS rates were comparable between the CAR-T cell group [91.0% (95% CI: 79.0%-100%)] and the control group [79.1% (95% CI: 66.0%-92.2%), P = 0.20]. Adverse events were well tolerated, and no patients experienced grade 3-4 cytokine release syndrome or any grade of immune effector cell-associated neurotoxicity syndrome. Hematological cytopenia was the most severe CAR-T cell related toxicity, but the toxicity was manageable, and only three patients experienced acute graft-versus-host disease following CAR-T cell infusion. Conclusions: Prophylactic or preemptive infusion of CAR-T cells after allo-HSCT demonstrated a reduced incidence of relapse and acceptable adverse events in high-risk B-ALL patients. These findings highlight the potential of CAR-T cell therapy as a promising strategy for relapse prevention in high-risk B-ALL patients after allo-HSCT.

Idecabtagene Vicleucel (ide-cel) Versus Standard (std) Regimens in Patients (pts) with Triple-Class-Exposed (TCE) Relapsed and Refractory Multiple Myeloma (RRMM): Updated Analysis from KarMMa-3

Introduction A single ide-cel infusion showed significantly longer median progression-free survival (PFS) vs std regimens (13.3 vs 4.4 months [mo], HR 0.49, 95% CI 0.38-0.65, P < 0.001) with deep, durable responses in heavily pretreated TCE RRMM at an interim analysis (IA) of KarMMa-3 (NCT03651128); safety data were consistent with prior studies (Rodríguez-Otero et al. NEJM 2023). Ide-cel benefits were consistent across pts in high-risk subgroups and across 2-4 prior lines of therapy (Tx). Results of the preplanned final PFS analysis of KarMMa-3 with 12.3 mo additional follow-up are reported. Methods In the phase 3 KarMMa-3 trial, pts with RRMM who received 2-4 prior regimens, including an immunomodulatory agent, proteasome inhibitor, and daratumumab, and were refractory to last regimen were randomized 2:1 to ide-cel or a std regimen (DPd, DVd, IRd, Kd, or EPd). In the ide-cel arm, pts could receive ≤ 1 cycle of optional bridging Tx for disease control. Pts in the std regimens arm could receive ide-cel after confirmed disease progression (PD). The primary endpoint was IRC-assessed PFS in the ITT population; final PFS was planned to be analyzed with ~289 events. Key secondary endpoints were IRC-assessed overall response rate (ORR) and overall survival (OS); other secondary endpoints included complete response rate (CRR), duration of response (DOR), minimal residual disease (MRD) status, time to next anti-myeloma Tx (TTNT; time from randomization to next anti-myeloma Tx [MTx]), event-free survival (EFS; time from randomization to first PD, next MTx or any-cause death, whichever is first), PFS2 (time from randomization to second objective PD or any-cause death, whichever is first), safety, and health-related quality of life (QOL). Results Of 386 randomized pts (ide-cel, n = 254; std regimens, n = 132), 225 received ide-cel and 126 received a std regimen. Baseline characteristics were generally balanced. Median follow-up from randomization to data cutoff (April 28, 2023) was 30.9 mo (range 12.7-47.8). Ide-cel significantly improved median PFS (95% CI) vs std regimens (13.8 [11.8-16.1] vs 4.4 [3.4-5.8] mo), representing a 51% reduced risk of PD or death (HR 0.49, 95% CI 0.38-0.63; Figure); 18 mo PFS rates were 41% vs 19%, respectively. Ide-cel significantly improved ORR vs std regimens (71% vs 42%) with deeper (CRR 44% vs 5%; ≥CR and MRD negative status [sensitivity level 10 -5], 22% vs 1%), more durable responses (median DOR 16.6 vs 9.7 mo; Table). PFS and ORR benefits of ide-cel vs std regimens were consistent with the IA. Interim OS will be included in the presentation. In pts who received ide-cel (n = 225) or a std regimen (n = 126), median PFS (95% CI) was 15.7 (12.5-18.9) vs 4.4 (3.4-5.8) mo, respectively. In the ITT population, median TTNT, EFS, and PFS2 were numerically longer with ide-cel vs std regimens. Median (range) TTNT was 20.9 (16.6-24.2) vs 7.0 (5.3-8.5) mo. Median (95% CI) EFS was 13.3 (11.3-15.7) vs 3.9 (3.0-5.3) mo. Median PFS2 (95% CI) was 23.5 (18.4-27.9) vs 16.7 (12.2-20.3) mo; ide-cel was next MTx in 70 (53%) pts in the std regimens arm. In the treated population, grade (gr) 3/4 infections occurred in 66/249 (27%) pts in the ide-cel arm vs 25/126 (20%) in the std regimens arm. In the ide-cel safety population, any gr cytokine release syndrome occurred in 197/225 (88%) pts, gr ≥ 3 in 11 (5%); median time to first onset was 1 d (1-14), median duration was 4 d (1-51). Any gr investigator-identified neurotoxicity occurred in 34/225 (15%) pts, gr ≥ 3 in 7 (3%); median time to onset was 3 d (range 1-317); median duration was 2.5 d (range 1-252). Ide-cel continued to demonstrate durable, clinically meaningful improvements in pt-reported outcomes, including symptoms, functioning, and QOL vs std regimens. Conclusions In this final PFS analysis of KarMMa-3, significantly longer PFS was maintained with ide-cel; PD or death risk reduced by 51%; responses were deeper and more durable vs std regimens. CRR with ide-cel increased since the IA, indicating a deepening response, but were unchanged with std regimens. A single ide-cel infusion vs continuous treatment with std regimens resulted in longer median TTNT and PFS2, indicating improved long-term disease control. The ide-cel safety profile was consistent with previous reports, with no parkinsonism or Guillain-Barré syndrome reported. These data continue to support use of ide-cel in pts with TCE RRMM. Study support 2seventy bio and Celgene, a Bristol-Myers Squibb Company.

Mixed Phenotypic Acute Leukemia -Clinical Presentation, Prognosis and Outcomes of Patients Treated with Acute Lymphoblastic Leukemia like Protocols a Multi-Institutional Study from India

Mixed phenotypic acute leukemia (MPAL) is a rare and difficult to treat type of acute leukemia. Broad consensus favour use of acute lymphoblastic leukemia (ALL) like treatment protocols in the management of MPAL. Data regarding this rare diagnosis is limited mainly to retrospective studies and limited data available from low middle income countries (LMIC). We report epidemiology and real-world outcome data of MPAL patients treated with ALL like protocols among the multi-institutional data base set up by hematology cancer consortium (HCC) in India. In this retrospective multicentric study of a prospectively maintained data set, we collected data from eleven member centers of HCC using an electronic database. Patients who fulfilled the WHO 2016 classification criteria for MPAL were included. Patients diagnosed between January 2018 and March 2022 were included in the study. The data included demographic details, performance status (ECOG), comorbidities, CNS involvement, testicular involvement, presence of mediastinal mass, phenotype of MPAL (B+M, T+M, T+B), karyotype, FISH, PCR and NGS abnormalities. If treatment was not received by patients the reasons were also captured. We also evaluated the treatment protocol used and use of tyrosine kinase inhibitors. The primary objective was to evaluate event-free survival (EFS) and overall survival (OS) at 1year. The impact of the treatment protocol used, age, baseline WBC count, LDH, performance status, CNS involvement on EFS and OS were studied. A total of 114 patients were diagnosed to have MPAL during the study period. The baseline epidemiological features are tabulated in table-1. Sixty-six (58%) patients were treated with ALL like treatment protocols and 48(42%) patients did not receive any treatment due to various reasons at HCC centers. 49(74%) patients received paediatric inspired protocols and 17(26%) patients received adult-type of protocols. Forty three (65%) patients achieved a complete remission after induction. Ten(15%) patients died during induction. Six(9%) patients died after achieving CR of which 3 died due to infection,3 died due to progressive disease and rest were lost to follow up. Minimal residual disease (MRD) done using either flowcytometry or PCR was available in 37 patients. MRD negative status was achieved in 17(46%) patients post phase II of induction. After a median follow up of 12 months, EFS was 61% and OS was 67%(figure1). Estimated EFS and OS at 24 months were 42% and 55% respectively. There were no significant differences in EFS and OS between different MPAL phenotypes. Allogeneic stem cell transplant (ASCT) was performed only in 3 patients. Negative MRD status at the end of second phase of induction was significantly associated with improved EFS with a Hazard ratio of 0.349(CI-0.117-1.036). Age, cytogenetic profile, LDH, baseline WBC count and CNS involvement were analyzed by univariate analysis for effect on treatment outcomes. There was no significant effect of these variables on both EFS and OS. Our study is one of the largest studies conducted on MPAL patients in a resource limited setting. If patients received treatment, the outcomes were encouraging despite poor access to allogeneic stem cell transplant in first complete remission, when compared with similar real world multi-institutional analysis. Induction mortality of 10% was comparable to other similar studies. However, the worse 2-year EFS and OS may be explained by poor rates of allogeneic stem cell transplant (Allo-HSCT). The abandonment of treatment and limited use of Allo-HSCT in first complete remission were major limitations in improving overall outcomes in our patients.

Inotuzumab Ozogamicin + Blinatumumab +/- Rituximab + Mini-Hcvd Shows Improved Tolerability with Similar Efficacy Compared to E1910 in Treatment of Philadelphia Chromosome Negative Acute Lymphoblastic Leukemia in Older Adults

CONCLUSION Philadelphia chromosome negative acute lymphoblastic leukemia (Ph- ALL) boasts contradicting survival rates given its binodal age distribution. While children and adolescents post 5-year overall survival (OS) rates of 89%, the stark contrast of 5-year OS of 20.4% in older adults greater than 65 years, makes this a challenging population to treat. Currently, there is no standard of care for the treatment of ALL with various regimens utilized dependent on age, co-morbidities, performance status, as well as physician/institute preference. One regimen that is commonly used is a combination of targeted therapies along with reduced intensity chemotherapy (inotuzumab ozogamicin, rituximab (if CD20+), blinatumomab and mini hyper fractionated cyclophosphamide, vincristine, and dexamethasone [Mini-HCVD]), which has demonstrated both improvements in survival while reducing treatment related toxicity. Another commonly accepted approach is a modified Berlin-Frankfurt-Munster (BFM) backbone (i.e., E1910). Despite the available options, there is a lack of comparison of these regimens. To answer this unanswered question, we compared the characteristics, outcomes, and toxicities of older adults with ALL treated with either Mini-HCVD or E1910 at our academic medical center. Medical records were retrospectively reviewed at Roswell Park Comprehensive Cancer Center to identify patients diagnosed with Ph- ALL treated with Mini-HCVD or E1910 between January 1 2016 - May 31 2022. Those with relapsed/refractory ALL or received E1910 in the setting of a clinical trial were excluded from the study. Demographics, disease-specific variables, and overall outcomes were collected in accordance with the institutional review board approved protocol. Primary outcome was 3-year overall survival rate, while secondary outcomes included best response in first 3 months, minimal residual disease (MRD) status at 3 months, 30-day mortality, as well as the frequency and incidence of toxicities per cycle. Best response was defined as less than 5% blasts on bone marrow biopsy with complete (CR) or incomplete (CRi) absolute neutrophil or platelet count recovery. MRD status was assessed via flow cytometry and next generation sequencing using ClonoSEQ®. Adverse events and their severity were characterized according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Differences in OS between two groups were examined by log-rank test. Propensity scores were obtained based on the baseline variables that with potentially imbalanced distributions (p<0.1). MRD status and response to treatment were compared using Fisher's exact test. Toxicities were summarized as frequencies for each treatment cycle. The incidence of grade 3-4 toxicities was defined as the number occurrence per treatment cycle and were compared using Poisson regression. 27 patients were included, with 15 (55.5%) receiving Mini-HCVD and 12 (44.5%) receiving E1910. Median age was 70 years (49-83), in Mini-HCVD arm and 63 years (47-74), in E1910 arm. Three-year OS was 61.9% for those who received Mini-HCVD (95% CI 40.2-95.3) and 28.1% for those who received E1910 (95% CI 10.9-72.9; p=0.23). In Mini-HCVD 77% and 69% of patients achieved CR/CRi and MRD negative status in the first three months, compared to 60% and 70% in E1910. Only 13% of patients in Mini-HCVD proceeded to transplant or CAR-T, compared to 58% in E1910 (p=0.0198). The most common treatment-related adverse events in both arms were cytopenias. Febrile neutropenia occurred in 47% of Mini-HCVD patients compared to 83% in E1910. There was no difference in rates of infections between arms. Mean incidence of grade 3/4 toxicity per cycle was 0.85/0.96 with Mini-HCVD and 1.03/1.65 with E1910 (p=0.0098). This retrospective single institute study demonstrates that the clinical outcomes of Mini-HCVD plus immunotherapeutic agents in older adults with Ph- ALL are similar to modified BFM backbone with reduced incidence of toxicity. While limited by small numbers, these results suggest that reduced intensity chemotherapy in combination with novel targeted agents could represent a new standard of care regimen in this historically difficult to treat patient population.

Early Peripheral Blood Blast Clearance As a Prognostic Marker for Early Treatment Response in Pediatric Acute Myeloid Leukemia

Background and Significance The cure rate of pediatric acute myeloid leukemia (AML) has improved significantly; however, relapses still occur in up to 30% of the total patient population in high-income countries (HICs), and in an even higher percentage of patients in low- and middle-income countries (LMICs). Early treatment response, cytogenetics and minimal residual disease (MRD) are well-known prognostic factors for treatment outcome; however, sophisticated techniques for identifying prognostic factors are often lacking in LMICs, and are sometimes unsuccessful in HICs. Early treatment response assessed by a bone marrow (BM) aspirate on day 15 or day 22 (D22) (depending on the applicable protocol) after initiation of chemotherapy is a known prognostic factor for outcome in patients with pediatric AML, but does not allow modifications of the first induction chemotherapy course (Creutzig 2014, Abrahamsson 2011, Kern 2003). In both pediatric acute lymphoid leukemia (ALL) and adult AML, early peripheral blood blast clearance (PBBC) is a known early indicator of treatment response (Manabe 2008, Arellano 2012), whereas to the best of our knowledge, this has not yet been reported in pediatric AML. In this study, we evaluated the significance of time to complete PBBC, and rate of PBBC after initiation of chemotherapy, in relation to disease status in BM D22, as measure of early treatment response that has prognostic significance. Study Design and Methods Pediatric patients with AML, aged 0-18 years, that were treated according to the NOPHO-DBH AML-2012 protocol were included. The first 5 days of induction therapy consisted of etoposide, followed by 7 days of low-dose cytarabine and mitoxantrone or liposomal daunorubicin. Peripheral blood (PB) was assessed by morphology at the time of diagnosis, daily in the first week, and thrice weekly until D22 or until occurrence of complete clearance of blasts. BM D22 was assessed by morphology and flow cytometry. A receiver operating characteristic (ROC) analysis was performed to evaluate the predictive power of days from starting chemotherapy to complete PBBC. The correlation between time to complete PBBC and BM D22 results was analyzed using a logistic regression model. Multivariable logistic regression models were applied for the association after adjusting for effects of other covariates. Rate of PBBC was defined as the percentage of the absolute PB blast count on the day of diagnosis that cleared with each day of therapy, on average, until D22 or the day of complete PBBC. Results In total, 319 patients were included, out of whom 241 were eligible for analysis, and 78 not eligible due to missing or incomplete data. Day 9 after initiation of chemotherapy was identified as the most discriminating cut-off point for predicting BM D22 response. Patients were categorized into early PBBC (≤9 days; n=159) and delayed PBBC (>9 days; n=82) groups. Early PBBC was associated with having <5% AML cells in BM D22 as assessed by both morphology (OR 3.11; P=0.005) and flow cytometry (OR 2.73; P=0.041). Early PBBC also showed a much lower likelihood of having >15% AML cells in BM D22 by morphology (OR 0.08; P=0.002). None of the early PBBC patients had >15% AML cells in BM D22 by flow cytometry. For 217 patients (selection due to missing data [n=24]), the rate of PBBC could be calculated, and a discriminative cut-off value of 11% was identified. Patients were categorized into high rate of PBBC (>11%; n=132) and low rate of PBBC (≤11%; n=85). High rate of PBBC was associated with having <5% AML cells in BM D22 by flow cytometry (OR 4.30; P=0.007) and negative MRD status (OR 2.02; P=0.004), while also showing a strong association with a lower likelihood of >15% AML cells in BM D22 (OR 0.11; P=0.007) by morphology. None of the high rate PBBC patients had >15% AML cells in BM D22 by flow cytometry. Conclusion Both early complete PBBC and rate of PBBC after initiation of chemotherapy holds promise as prognostic marker for clinical outcome in pediatric AML, as it correlates significantly with BM D22 response. These findings may offer an early and easily accessible prognostic factor, particularly beneficial for LMICs, as well as for patients with unsuccessful MRD analyses.

High Efficacy and Feasibility of a Full Pediatric Induction in Adults Aged up to 55 Years with Philadelphia-Negative Acute Lymphoblastic Leukemia

Background: Treatment of acute lymphoblastic leukemia (ALL) in adults has historically shown unsatisfactory outcomes when compared to the outstanding results obtained in pediatric patients. Pediatric protocols rely on increased drug intensity and on a tighter evaluation of minimal residual disease (MRD) for early intensification. Nowadays, pediatric-inspired protocols have been established as the standard of care for adolescents and young adult patients (AYA) leading to improved results. In the setting of older patients, probably due to the limited data available, the feasibility of such intensive therapies, and in particular the administration of high doses PEG-asparaginase (PEGASP), is still a matter of debate. In this context, the NOPHO group reported that a full-pediatric protocol was feasible and highly effective in adult patients, up to 45 years of age. Aim: The aim of our study was to evaluate the feasibility and efficacy of the entire full pediatric AIEOP-BFM LAL 2009 protocol in an older cohort of adult patients up to 55 years. Methods: Since May 2013, 28 consecutive adults diagnosed with Ph-neg ALL received first line therapy according to AIEOP- BFM-ALL 2009 protocol, which includes high PEG-asparaginase (PEGASP) doses, with an accurate MRD-driven therapeutic strategy. The protocol consists of 2 induction blocks: IA (Vincristine, Daunorubicin, PEGASP, IT methotrexate) and IB (Cytarabine, 6-mercaptopurine, cyclophosphamide, IT methotrexate), I consolidation block (high-dose methotrexate, 6-mercaptopurine, IT methotrexate), maintenance therapy (6-mercaptopurine, weekly MTX, IT Methotrexate). Median age in our study was 45 years (range 17-55), equal to the maximum age allowed in the NOPHO study. Fifteen patients had B-ALL, 13 T-ALL/T including 5 Early-T phenotype. Dose intensification and stem cell transplantation (SCT) were scheduled according to baseline and MRD-driven risk assessment. MRD was evaluated by multicolor-flow cytometry (MFC), with a threshold for positivity of 0.025%, and molecular PCR for JH rearrangement (MOL), with a sensitivity greater or equal to 10-4 in all patients. Patients with MOL MRD >10-4 but <10-3 were defined as low-level positive. MRD time points were day 33 and day 78 (MFC and MOL). Results: All patients achieved complete hematological remission following the first Induction course (100%). One patient died during induction due to infection by multidrug resistant P. aeruginosa. In general, therapy was well tolerated. Remarkably, patients in this study received high dose of PEGASP (median 10000 UI/sqm, equal to 4 administrations at 2500 UI/sqm each) without experimenting life threatening toxicities, which mostly consisted in asymptomatic elevation of transaminase (7 patients G3, 1 G4) and/or bilirubin (9 patients G3, 1 G4) only requiring supportive therapy. No major bleeding or thrombotic events o other >G2 toxicities were observed. All except one patient achieved CR at day 33 and all patients achieved CR at day 78. MFC MRD evaluation at day 33 resulted negative in 24/25 evaluable patients (95%). Day 33 MOL-MRD was evaluated in 22 patients, and resulted negative, low level positive or positive in 14, 5 and 3 patients, respectively. MRD assessment at day 78 showed both MFC and MOL negativity achieved in all 25 and 22 evaluated patients, respectively (Fig. 1). Four very high-risk patients underwent SCT in negative MRD status. After a median follow-up of 59 months (CI 95% 38.45-78.63), median survival was not reached, 5-years OS was 88.7% (Fig. 2). One patient died due to progressive transverse myelitis after isolated CNS relapse and one patient died due to sudden cardiac arrest while in complete MRD negative remission, 6 months after completion of therapy. All other 25 patients are alive and in complete MRD negative remission. Conclusion: The application of a full pediatric induction regimen in a cohort of adult ALL patients with a median age of 45 years proved to be feasible, with tolerable toxicities. In particular, we didn't observe major toxicities during the intensified PEGASP administration and all patients were able to receive the planned PEGASP doses. The possibility to maintain the correct timing translated in a very high MRD negativity rate and promising OS survival.

Inotuzumab Ozogamicin in Lymphoid B Cell Malignancy：a Single Center Analysis in the Real World

Background : Recent developments in immunoconjugate usage has changed the landscape of lymphoid B-cell malignancy therapy. Historically, those who relapse from this condition have a dismal prognosis and limited treatment options. One recent development is the inotuzumab ozogamicin (INO), a humanized anti-CD22 monoclonal antibody conjugated to the cytotoxic antibiotic calicheamicin, which has the potential to reduce the overall toxicity of intensive regimens for ALL, as well as to show therapeutic effects in lymphoid B-cell malignancy. Aims and Methods: The study included B cell-acute lymphoblastic leukemia (B-ALL) (n=23), B/ myeloid mixed phenotype acute leukemia (MPAL) (n=1) and B-cell lymphoblastic lymphoma (B-LBL) (n=3) adult patients who received INO in our center from June 2022 to June 2023. Intravenous INO was given 1 or more doses at the dose of 0.6mg/m2, its clinical efficacy and adverse reactions were explored. Results: In our center, INO was strategically employed in various therapeutic scenarios: induction (n=2), maintenance/consolidation (n=6), minimal residual disease (MRD) clearance (n=5), and the management of relapsed/refractory lymphoid B-cell malignancies (n=14). Of the 27 patients, 14 were subjected to a combination regimen of INO and chemotherapy for recurrent and refractory lymphoid B-cell malignancy. The composition of these patients comprised of 4 individuals who experienced a relapse post-standard chemotherapy, 1 patient with a relapse post-allogeneic hematopoietic stem cell transplantation (allo-HSCT), 4 patients with a relapse post-autologous hematopoietic stem cell transplantation (auto-HSCT), and the remaining 5 patients were categorized as refractory cases. The median number of doses administered was 2 (1-3). Complete remission (CR) or CR with incomplete hematologic recovery (CRi) was observed in 9 out of 14 patients (64.3%) within a median duration of 30 (16-78)days. Partial response (PR) was noted in 2 of the 14 patients (14.3%), rendering the overall response rate (ORR) to be 78.6%. Negative MRD was observed in 7 out of 14 patients (50.0%). Of the 9 patients who achieved CR/CRi, 4 (44.4%) relapsed again with 2 fatalities. The remaining 2 patients attained negative MRD following a second allo-HSCT or INO retreatment. The two patients who achieved PR proceeded to receive chimeric antigen receptor T cell (CART) treatment, with one of them subsequently undergoing allo-HSCT after achieving CR. For the three non-responders (NR), one patient unfortunately passed away while the other two patients remained alive and were either participating in clinical trials or undergoing allo-HSCT after CART. For MRD clearance, it was successfully achieved in 4 out of 5 patients (80.0%)treated with INO within a median period of 45 (28-52)days. However, 2 patients reverted to MRD positivity and 1 died. The other four patients underwent allo-HSCT with neither mortality nor recurrence observed. Moreover, two patients (100%) were treated with a VICLP induction regimen combined with INO, with MRD negativity observed post-treatment. Regarding the remaining six patients, three patients were treated with INO as consolidation therapy due to high-risk factors or the intention to undergo auto-HSCT. Another 3 B-ALL patients treated with INO as maintenance therapy after auto-HSCT or after the remission of recurrence after transplantation. One patient unfortunately experienced a second recurrence four months following INO maintenance. The remaining five patients achieved and have since sustained negative MRD status, preceding INO treatment. Fortunately, no treatment-related fatalities or treatment discontinuation due to adverse events were observed. Notably, 19 out of 27 patients (70.4%) experienced Grade 3-4 hematological toxicity, while 1 out of 24 patients (4.2%) exhibited Grade 3 alanine aminotransferase (ALT) elevation. Veno-occlusive disease (VOD) was not observed. Furthermore, two patients developed septicemia, one each from Escherichia coli and Klebsiella pneumoniae, respectively. Conclusions: Given the well tolerance and improvement in response rates, InO may be an important treatment option not only for patients with relapsed/refractory lymphoid B-cell malignancy, but also for induction, maintenance and MRD clearance treatment. Key words: inotuzumab ozogamicin, acute lymphoblastic leukemia, hematopoietic stem cell transplantation, CD22

CAR-T Therapy in Relapsed Refractory Multiple Myeloma.

Multiple myeloma is a plasma cell neoplasm. The emergence of proteasome inhibitors, immunomodulatory drugs, and anti-CD38 monoclonal antibodies has improved the prognosis of multiple myeloma patients. However, some patients are still insensitive to conventional therapy or frequently relapse after remission. Chemotherapy based on proteasome inhibitors or immunomodulatory drugs is ineffective in controlling the progression of relapsed refractory multiple myeloma. No consensus has been reached on treating relapsed refractory multiple myeloma to date. Recently chimeric antigen receptor T cells therapy has shown promising results that could achieve rapid remissions of patients and improve their prognoses. Additionally, most patients in chimeric antigen receptor T cell clinical trials were triple-refractory multiple myeloma patients, indicating that chimeric antigen receptor T cell immunotherapy could overcome drug resistance to new drugs. Since single immunotherapies are prone to acquired resistance, combination immunotherapies based on emerging immunotherapies may solve this issue. Achieving complete remission and minimal residual disease negative status as soon as possible is beneficial to patients. This paper reviewed the main chimeric antigen receptor T cell products in relapsed refractory multiple myeloma, and it explained the drug resistance mechanism and improvement methods of chimeric antigen receptor T cells therapy. This review summarized the best beneficiaries of chimeric antigen receptor T cell therapy and the salvage treatment of disease recurrence after chimeric antigen receptor T cell therapy, providing some ideas for the clinical application of chimeric antigen receptor T cells.

Immunophenotypic correlates of sustained MRD negativity in patients with multiple myeloma

The role of the immune microenvironment in maintaining disease remission in patients with multiple myeloma (MM) is not well understood. In this study, we comprehensively profile the immune system in patients with newly diagnosed MM receiving continuous lenalidomide maintenance therapy with the aim of discovering correlates of long-term treatment response. Leveraging single-cell RNA sequencing and T cell receptor β sequencing of the peripheral blood and CyTOF mass cytometry of the bone marrow, we longitudinally characterize the immune landscape in 23 patients before and one year after lenalidomide exposure. We compare patients achieving sustained minimal residual disease (MRD) negativity to patients who never achieved or were unable to maintain MRD negativity. We observe that the composition of the immune microenvironment in both the blood and the marrow varied substantially according to both MRD negative status and history of autologous stem cell transplant, supporting the hypothesis that the immune microenvironment influences the depth and duration of treatment response.

Molecular genetic and cytofluorimetric prognostic factors in the development of acute myeloid leukemia relapse in children after allogeneic hematopoietic stem cell transplantation

   Relapse of acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains one of the main causes of reduced long-term survival. Modern methods for predicting the risk of AML relapse after allo-HSCT take into account the data on the pre-transplant level of minimal residual disease (MRD) determined by flow cytometry and molecular biological studies of recurrent genetic abnormalities, which are currently widespread in clinical practice. Recent studies of the expression of genes characteristic of leukemic stem cells (LSCs) have shown prognostic significance for children with AML in relation to treatment response and the risk of relapse. The study of LSC persistence in order to predict the risk of recurrence after allo-HSCT in children with AML in addition to standard MRD detection methods may be of great importance. The aim of the work was to evaluate the impact of MRD status, both using classic methods and taking into account the genes characteristic of LSC, on the results of allo-HSCT in children with AML. The study was approved by the Independent Ethics Committee and the Scientific Council of the I.P. Pavlov First Saint Petersburg State Medical University of Ministry of Healthcare of the Russian Federation. To assess MRD using standard diagnostic methods, we analyzed the data of 95 children with AML in their 1st–2nd remission (cohort 1). MRD status was negative in 67 (70.6 %) patients; in 28 (29.4 %) children, MRD status was positive according to molecular genetic studies and / or immunophenotyping results. For pre-transplant evaluation of the expression of genes characteristic of LSC, we investigated bone marrow samples of 50 patients (cohort 2) using real-time polymerase chain reaction. The DNMT3B, GPR56, CD34, SOCS2, SPINK2, FAM30A, and ABL genes were studied by real-time polymerase chain reaction, followed by calculation of the pLSC6 value using the formula: DNMT3b × 0.189 + GPR56 × 0.054 + CD34 × 0.0171 + SOCS2 × 0.141 + SPINK2 × 0.109 + FAM30A × 0.0516. At the time of allo-HSCT, 37 (74 %) children with AML were in their 1st or 2nd remission of the disease, 13 (26 %) were out of the 1st–2nd remission. With a median follow-up of 5 years in the group of patients with a positive MRD status, determined by standard methods (cohort 1), overall survival (OS) was 67.9 % vs 73.1 % for patients with a negative MRD status (p = 0.83). The cumulative incidence of relapse was 50 % and 22 %, respectively; p = 0.012. When assessing the level of expression of genes characteristic of LSC (cohort 2), a pLSC6 level was above the median in 18/37 (49 %) patients. The results of linear regression showed that the pre-transplant level of expression of genes characteristic of LSC was not associated with the number of blasts/MRD (odds ratio 1.002; 95 % confidence interval 0.979–1.025). One-year OS rates did not differ significantly in children in the 1st–2nd remission of AML, depending on pLSC6 level: 84.2% in patients with low pLSC6 and 72.2 % – with high pLSC6 (p = 0.4), event-free survival in the corresponding groups – 68.4 % and 61.1 %, respectively (p = 0.34). The cumulative incidence of early relapse after allo-HSCT in the group of AML patients with a high pLSC6 score was significantly higher than in children with a low pLSC6 score before allo-HSCT (22 % and 0 %, respectively; p = 0.03). MRD does not have a statistically significant effect on OS. However, MRD positivity before allo-HSCT increases cumulative incidence of relapse. The level of expression of genes characteristic of LSC, determined before allo-HSCT, showed a prognostic significance in relation to the development of early AML relapse after allo-HSCT.

Prognostic value of early bone marrow MRD status in CAR-T therapy for myeloma

Bone marrow (BM) assessment of minimal residual disease (MRD) is prognostic for survival in multiple myeloma (MM). BM is still hypocellular at month 1 post CAR-T, thus the value of MRD negative (MRDneg) status at this timepoint is unclear. We examined the impact of month 1 BM MRD status in MM patients who received CART at Mayo Clinic between 8/2016 and 6/2021. Among 60 patients, 78% were BM-MRDneg at month 1; and 85% (40/47) of these patients also had decreased to less than normal level of both involved and uninvolved free light chain (FLC < NL). Patients who achieved CR/sCR had higher rates of month 1 BM-MRDneg and FLC < NL. The rate of sustained BM-MRDneg was 40% (19/47). Rate of conversion from MRDpos to MRDneg was 5%(1/20). At month 1, 38%(18/47) of the BM-MRDneg were hypocellular. Recovery to normal cellularity was observed in 50%(7/14) with a median time to normalization at 12 months (range: 3–Not reached). Compared to Month 1 BM-MRDpos patients, patients who were BM-MRDneg had longer PFS irrespective of BM cellularity [PFS: 2.9 months (95% CI, 1.2-NR) vs. 17.5 months (95% CI, 10.4-NR), p < 0.0001]. Month 1 BM-MRDneg and FLC below normal were associated with prolonged survival. Our data support the continued evaluation of BM early post-CART infusion as a prognostic tool.

Free from Maintenance Drug Therapy in Multiple Myeloma (The FREEDMM Trial): A Pilot Study of Minimal Residual Disease (MRD)-Driven Discontinuation of Maintenance

Background Induction therapy followed by autologous stem cell transplant (ASCT) and maintenance is the current standard of care for the treatment of newly diagnosed multiple myeloma (NDMM). However, indefinite maintenance therapy after ASCT carries both significant clinical and financial toxicities. While minimal residual disease (MRD) testing has become part of routine standard of care, its use in guiding treatment decisions, in particular cessation of therapy, has not been established in the maintenance setting. We hypothesize that MRD monitoring could be used to guide clinical decision making, justifying cessation of maintenance therapy in a sub-group of patients with sustained MRD-negative remission. Study Design and Methods This is a phase 2 single-arm adaptive design study (NCT 05192122) for decision-making regarding maintenance therapy (Figure 1). Patients are eligible if they have a diagnosis of active MM, have completed at least 2 years of maintenance therapy post-ASCT, and meet International Myeloma Working Group (IMWG) criteria for very good partial response (VGPR) or complete response (CR). MRD testing is performed twice, at least one year apart, on bone marrow aspirate using next-generation sequencing (NGS) and MRD-negative status is defined at a threshold of 10-6. Patients with negative PET scan in VGPR or CR and sustained (i.e., twice, 1 year apart) MRD negative status discontinue maintenance therapy. MRD-positive patients continue continue maintenance and are taken off study. In patients who are MRD-negative and discontinue maintenance therapy, MRD testing will be re-assessed yearly for 3 years. At each time of MRD testing, MALDI-TOF spectrometry and measurement of circulating multiple myeloma cells (CMMCs) will be done in parallel to compare against MRD results. Health-related quality of life (HRQoL) will be assessed throughout and results on maintenance compared with those after discontinuation using the EORTC QLQ-MY20 questionnaire. This study will enroll 50 patients to address the primary objective of assessment for sustained MRD-negative status at 12 months after stopping maintenance therapy. For all patients, a 5-mL peripheral blood and bone marrow sample is collected and stored at the time of each standard of care bone marrow biopsy and will be used to characterize the immune microenvironment by Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) of paired peripheral blood and bone marrow in MRD-negative and MRD-positive patients as well as of patients progressing after stopping therapy. Preliminary Results Enrollment into FREEDMM trial began in December 2021, and to date 20 patients in CR have undergone a first bone marrow for MRD assessment, with results pending in 9 patients. The median age is 66.5 (range: 39-76) years, and the majority of patients are either Black (n=7; 35%) or Hispanic (n=7; 35%). One patient has high risk disease (17p deletion). The median number of years of maintenance therapy completed is 4.2 (range: 2.14-7.9) years. 17 (85%) patients had a negative MALDI-TOF test at the time of the first marrow. Seven (63.6%) of 11 patients were found to be MRD-negative. MALDI-TOF failed to accurately correlate with MRD results in 2 patients. 40 paired peripheral blood (n=20) and bone marrow aspirate (n=20) samples have been collected for CITE-seq analysis. Pilot CITE-seq experiments captured 6,700-11,000 cells with between 38,000-68,000 reads per cell on one MRD-negative and one MRD-positive bone marrow aspirate and paired peripheral blood sample. CITE-seq results for these 20 patients will be presented at the conference. Conclusion: This phase 2 trial applies a novel clinical trial design with an adaptive strategy to explore use of MRD testing as a guide to discontinuing maintenance therapy in myeloma and represents one of the first studies to explore in parallel various measures of disease monitoring (i.e., MRD, MALDI-TOF, CMMCs, CITE-seq). Ongoing results will be reported at the conference. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Interim Results of a Risk-Adaptive Phase II Study: Carfilzomib, Lenalidomide, Dexamethasone and Daratumumab (KRD-Dara) in Newly Diagnosed Multiple Myeloma (NDMM) at the Levine Cancer Institute (LCI)

Background: The combination of carfilzomib, lenalidomide and dexamethasone (KRd) has previously demonstrated deep and durable responses in patients with NDMM. A quadruplet regimen incorporating daratumumab (KRd-Dara) may further improve results. We report an interim analysis from stage 1 (Simon's optimal 2-stage design) of an ongoing minimal residual disease (MRD)-driven, single center phase 2 trial of KRd-Dara. Methods: The study design has been previously published (Bhutani et al, Blood 2020 Abstr 1388). Briefly, patients with NDMM (both transplant eligible and ineligible) were allowed one cycle of non-protocol therapy (if deemed necessary) and then 7 or 8 cycles of induction therapy with KRd-Dara (total induction cycles: 8). MRD assessment was performed by both next generation sequencing (NGS) and next generation flow cytometry (NGF) at the end of 8 cycles of induction, post- autologous stem cell transplantation (ASCT), and every 4 cycles of consolidation (maximum of 12 cycles). Post-induction treatment was dictated by an MRD-driven algorithm, using MRD (NGS, 10-5) to assign patients to one of the 3 study groups. The primary endpoint is complete response (CR) + stringent CR (sCR) at the completion of KRd-Dara induction therapy. Group A (MRD negative post-induction) proceeded directly to lenalidomide maintenance therapy deferring ASCT, if transplant eligible. Group B (MRD positive, transplant eligible) received upfront ASCT, KRd consolidation (maximum 12 cycles), and then lenalidomide maintenance. Group C (MRD positive after 8 cycles of induction, transplant ineligible) received KRd consolidation (maximum 12 cycles) followed by lenalidomide maintenance. Conversion to MRD negative status at any protocol specified time point allowed the patients to proceed to lenalidomide maintenance. Results: Stage 1 futility analysis criteria were met in November 2021 and stage 2 enrollment is actively ongoing. As of a data cutoff of 4/8/22, 30/39 patients have been enrolled. Twenty-three patients were enrolled in Stage 1. The median age of stage I patients was 60 (range 34- 76) years, 74% were male and 35% were Black. R-ISS stage 3 was present in 2 (8.7%), high-risk cytogenetics in 1 (4.4%) and gain 1q21 in 7 (30.4%). Fifteen patients (65.2%) received one cycle of pre-study treatment. All patients completed 8 total cycles of induction therapy. At the end of induction, CR + sCR was achieved in 15/23 (65.2%) patients with sCR in 52.2%, and very good partial response (VGPR) in 7 (30.4%). The MRD negativity rate was 69.6% (NGS, 10-5) and 43.5% (NGS, 10-6). The MRD negativity rate by NGF was 82.6% at 10-5and 47.4% at 10-6 sensitivity level in 23 and 19 evaluable patients, respectively; 43% of bone marrow specimen tested by NGF were hemodiluted. Concordance of MRD by NGS/ NGF at 10-5 was 16/23 (69.6% in agreement and 30.4% disagreement, Cohen's kappa: 0.183). Concordance of MRD by NGS/ NGF at 10-6 was 12/19 (63.2% in agreement and 36.8% disagreement, Cohen's kappa: 0.257). Grade 3-4 treatment related adverse events (>10% of patients) included hypophosphatemia (30%), hypertension (13%), and neutropenia (13%). Covid infection occurred in 7 (30.4%) patients; only one needed hospitalization. Other Infections (any grade) were seen in 15 (65.2%) patients. At least one dose reduction of carfilzomib was required in 5 (21.7%) patients, dexamethasone in 3 patients, and lenalidomide in 4 patients. Systemic injection reactions to subcutaneous daratumumab occurred in 5 (21.7%). Thromboembolic events happened in 3 patients. No patient discontinued treatment because of toxicity. There was no treatment-related mortality during stage 1. Post-induction, 16 patients (MRD negative) transitioned to lenalidomide maintenance, 5 patients (MRD positive) underwent ASCT, and 2 patients (MRD positive) proceeded to consolidation phase. Stem cell collection for eligible patients (n=22) was performed upon completion of induction; 5 patients failed to collect optimal target (3 million CD34+ cells/kg) during their first mobilization attempt. Survival results will be updated after stage 2 enrollment is completed, but as of data cutoff, no subjects in the Stage 1 cohort have progressed. Conclusions: The quadruplet regimen KRd-Dara as induction in NDMM leads to deep responses reflected in high rates of sCR and MRD negativity with an acceptable and well-tolerated safety profile. The stage 2 enrollment is ongoing.

Maintenance Therapy Cessation for Sustained MRD Negative Multiple Myeloma Patients

Introduction Maintenance therapy with lenalidomide (len) and other drugs is a cornerstone therapeutic strategy for sustaining deep durable remissions in multiple myeloma (MM). However, indefinite treatment, as currently recommended, may lead to financial, emotional, and physical toxicity. Current guidelines lack data on optimal duration of maintenance in MM patients (pts) who have achieved sustained negative minimal residual disease (MRD) status. Here, we present the first pre-planned interim results from a phase II study evaluating maintenance cessation in patients with sustained MRD negative status for at least 3 years at the time of enrollment on study. Methods The current two-stage designed study of fifty MM pts, having already demonstrated >3 years of durable MRD negative responses, will be evaluated for MRD negative sustainability after ceasing maintenance therapy. Enrolled pts stop maintenance therapy and undergo active surveillance for three years, including serum protein testing every 3 months, bone marrow MRD testing by multiparametric flow cytometry (single 10-color tube with limit of detection of at least 6x106 (6 cells in 1 million) every 6 months, and annual PET-CTs. Primary endpoint includes sustained MRD negative rate after 1 year. Secondary endpoints include sustained MRD negative rate 3 years of cessation, re-treatment responses, microbiome and immune studies, health-related quality of life outcomes (HRQoL), and progression-free survival (PFS). The first stage includes 15 pts, and if 8 or more remain MRD negative at the end of 1 year, study enrollment continues to stage two (n=35). Results At data cutoff, on July 31, 2022, twenty-three pts (15 - stage 1; 8 - stage 2) have been enrolled on study. Median follow-up was 14.8 months (95% LL-UL: 11.1 - 25.1) after study enrollment, included 17(74%) male and 6(26%) female; 19(83%) ISS-stage 1, 2(9%) ISS-stage 2, and 2(9%) ISS-stage 3; and 4(17.3%) pts with high-risk cytogenetics [1 - t(4,14) and t(14,16); 1 - t(4,14) and +1q21gain; 2 - +1q21gain]. All pts enrolled onto study were receiving lenalidomide maintenance at the time. For stage 1, 13/15 (87%) remained MRD negative at 12 months of stopping maintenance therapy, and study accrual is ongoing with enrollment of 8 additional pts onto second stage. Overall, MRD negative sustained rates at 6 months and 12 months are 17/18 (94%) (95% CI: 73%-99%) and 14/16 (88%) (95% CI: 62%-98%), respectively. Progression free survival at 12 months was 94% (95% CI: 83%-100%). Two pts converted from MRD negative to MRD positive disease states while meeting clinical progression criteria with new FDG avid bone lesions. These pts have transitioned to new regimens: Pt 13 initiated carfilzomib, pomalidomide, and dexamethasone with VGPR; Pt 2 with a plan to initiate daratumamab-based therapy locally. Pt 10 converted to MRD positivity without clinical progression and opted to restart maintenance therapy with repeat MRD testing pending. Among the three MRD converters, one pt demonstrated standard risk cytogenetics and two pts had unknown risk cytogenetics. Additional HRQoL outcome data will be presented at the time of the meeting. Conclusions Initial first stage results of stopping maintenance in sustained MRD negative patients (>3 years) warrants further investigation and study continuation. This study and similar ones, such as MRD2STOP (NCT04108624), set a benchmark for future trials investigating maintenance cessation. One such trial includes SWOG 1803, which randomizes maintenance continuation vs. discontinuation in two-year MRD negative sustained patients. While maintenance therapy demonstrates clear benefit for MM patients, feasibility of treatment-free periods remain an unanswered critical question in the field. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Trial in Progress: A Phase II Window of Opportunity Study of the BCMAxCD3 Bispecific Antibody REGN5458 in Previously Untreated Patients with Symptomatic Multiple Myeloma

Background Treatment of multiple myeloma (MM) has advanced significantly in the last 20 years, resulting in improved survival. For patients with newly diagnosed MM (NDMM) who are fit with no comorbidities, currently recommended treatment includes induction with triplets such as bortezomib, lenalidomide, and dexamethasone (VRd), followed by high-dose chemotherapy (HDT) and autologous stem cell transplantation (ASCT), and maintenance therapy using predominantly immunomodulatory agents. Patients who are elderly or ineligible for HDT/ASCT receive multiple drug combination therapies such as VRd or daratumumab with Rd. Despite the availability of these combinations, induction therapy does not induce complete remission with minimal residual disease negativity in all patients, and triplet- or quadruplet-based regimens are expensive and associated with enhanced toxicities including to stem cells. Moreover, MM remains incurable and new therapies with alternative mechanisms may improve or maintain the safety profile while increasing or deepening responses for longer periods. B-cell maturation antigen (BCMA) is a cell surface protein expressed on malignant plasma cells (Lee, et al. Br J Haematol. 2016;176:911-22). Notably, BCMA is detected only at low levels on normal plasma cells, activated B cells, and plasmacytoid dendritic cells, making it an attractive therapeutic target for MM. REGN5458 is a BCMA×CD3 bispecific antibody capable of binding to BCMA on MM cells and CD3 on T cells, inducing T-cell mediated cytotoxicity of MM cells. REGN5458 monotherapy has demonstrated early, deep, and durable responses with a manageable safety and tolerability profile in patients with relapsed/refractory (R/R) MM (NCT03761108; Zonder, et al. EHA 2022. Abstract S189) with a response rate of 75% among patients treated at the 200-800 mg dose levels. Cytokine release syndrome was reported in 38% of patients and was mostly Grade 1, with no Grade ≥3 events. Given the single agent efficacy and tolerability of REGN5458 in heavily pre-treated patients with R/R MM, its use in patients with NDMM (who are thought to potentially have improved T-cell fitness versus R/R patients) is hypothesized to have enhanced therapeutic benefit. Study Design and Methods This open-label, Phase II study aims to assess the safety, tolerability, pharmacokinetics (PK), and preliminary efficacy of REGN5458 monotherapy in patients with NDMM who are eligible or ineligible for HDT/ASCT. Transplant-eligible patients will receive REGN5458 induction, HDT/ASCT, followed by REGN5458 consolidation, and standard of care maintenance therapy. Transplant-ineligible patients will receive REGN5458 until disease progression or other discontinuation criteria are met (Figure). The primary objectives during part 1 are to assess safety and tolerability and to determine a recommended regimen for expansion. The objective for dose expansion is to assess preliminary antitumor activity. Secondary objectives are to evaluate the PK properties and immunogenicity of REGN5458 as well as soluble BCMA concentrations in serum at baseline and over time. The primary endpoints for part 1 are: the incidence of dose-limiting toxicities (DLTs) from the first dose of study drug to the end of the DLT observation period; the incidence and severity of treatment-emergent adverse events and adverse events of special interest with REGN5458 through study completion; for expansion: the proportion of patients with a very good partial response or better as determined by the investigator using International Myeloma Working Group response criteria; and the proportion of patients achieving minimal residual disease-negative status (at 10-5). Patients will have a window of opportunity to benefit from treatment; patients who do not meet the specified efficacy thresholds will transition to standard of care therapies. Approximately 92 patients are planned for this study. Eligibility criteria include age ≥18 years; ECOG PS 0-2; histologically or cytologically confirmed symptomatic MM; measurable disease; no prior therapy for MM, except radiation on an emergency/palliative basis or 1 month of single-agent corticosteroid if the patient still has measurable disease; and adequate bone marrow reserves, hepatic, renal, and cardiac function. The study will take place in approximately 20 sites located in North America and Europe. There are no formal hypothesis tests for this study. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal