Minimal Residual Disease Evaluation Research Articles

PB2005: BORTEZOMIB, LENALIDOMIDE AND DEXAMETHASONE IN NEWLY DIAGNOSED MULTIPLE MYELOMA PATIENTS: A REAL-WORLD STUDY OF CHINA

Background: Multiple myeloma (MM) is a hematological malignancy characterized by the malignant proliferation of monoclonal plasma cells. In recent years, a series of new drugs such as proteasome inhibitors, immunomodulatory drugs and autologous hematopoietic stem cell transplantation (ASCT) have been widely used in MM patients and have prolonged the survival of them. Nowadays Bortezomib/lenalidomide/dexamethasone (VRD) is considered as the first-line induction therapy for newly diagnosed multiple myeloma (NDMM) in most clinical guidelines. However the data of VRD in China is insufficient. Aims: To evaluate the efficacy of VRD in NDMM patients as well as the effect of the regimen on the stem cell collection and on the long-term prognosis in the real world. Methods: The clinical characteristics, survival rates, response rates and minimal residual disease (MRD) of 87 NDMM patients at Institute of Hematology & Blood Diseases Hospital from January 1, 2013 to January 1, 2020 were retrospectively analyzed and the impact of lenalidomide on stem cell collection was evaluated. Response was evaluated after 2 courses of induction therapy, before ASCT and at day100 after ASCT. The best response was defined as the deepest response during the follow-up. MRD was evaluated by multiparameter flow cytometry (MFC) with 10-4 sensitivity. Results: The median age of the patients was 56 years old (36-78) and males and females accounted for 58.6% and 41.4%, respectively. The overall response rate (ORR) was 95.9% after 2 courses of induction therapy, with 13.5% achieving the deep response (complete response (CR) or better) and 51.3% of patients achieving a very good partial response (VGPR) or better. After 4 courses of induction therapy, the ORR achieved 95.2%, and the proportions of the deep response and VGPR or better grew up to 46.0% and 77.7%. According to the treatment, the patients were divided into transplantation group and non-transplantation group. After the induction therapy, 88.8% of patients in the transplantation group achieved VGPR or better, and 55.5% reached the deep response. After the transplantation, the proportion increased to 97.2% (P=0.174) and 77.2% (P=0.055), respectively, with the rate of undetectable MRD increasing from 44.4% to 77.8% (P=0.004). In the non-transplantation group, 78.9% of patients achieved VGPR or better after 4 courses of induction therapy, 44.7% of the patients achieved deep response and the rate of undetectable MRD was 42.4%. Compared with the non-transplantation group, transplantation was associated with a higher rate of response (P＜0.001) and a lower rate of MRD detection(78.4% vs 57.1%, P=0.053). The median follow-up time of all patients was 26.3 months (6.2-61.4). The median PFS and OS were not reached. The three-year PFS and OS rates were 82.1% and 87.0%, respectively. None of the standard-risk group, the high-risk group, the transplantation group and non-transplantation group achieved the median PFS and OS. The number of CD34+ positive cells tended to decrease after more than 4 courses of VRD induction therapies. Image:Summary/Conclusion: VRD regimen is highly effective and results in a substantial survival benefit. VRD followed by ASCT is associated with higher rate of deep response, lower rate of undetectable MRD and longer survival.

PB1792: NGS VS PCR FOR THE DETECTION OF NPM1 GENE MUTATIONS IN ACUTE MYELOID LEUKEMIA.

Background:NPM1 gene mutations are found in 30% of acute myeloid leukemia (AML) cases. It is a reliable marker for the evaluation of therapy outcome and minimal residual disease (MRD) monitoring. The most often mutations are 4bp insertions in exon 12, affecting 2 functionally important tryptophan residues (W288 and W290) in the C-terminal region of nucleophosmin and causing a frameshift. As a result, a leucine-rich motif (L-xxx-V-xx-V-x-L) is formed, which is a signal sequence for protein export from the nucleus to the cytoplasm. Commonly NPM1 gene mutations are detected by fragment analysis (FA) of PCR fragment of 12 exon for the presence of 4bp insert. Alternatively, allele-specific polymerase chain reaction (AS-PCR) to detect inserts belonging to the A, B, or D type (representing up to 90% of all inserts) is used. However, about 10% remaining cases are non-standard inserts and intron polymorphisms that require more precise evaluation. Aims: Evaluation of diverse approaches for efficient NPM1 gene mutation analysis and their robustness for the diagnostics. Methods: The study included 80 DNA samples from AML patients admitted to the National Research Center for Hematology in 2019-2021 that were positive for NPM1 gene mutations detected by FA performed with the Nanophor-5 genetic analyzer (Synthol, Russia). The type of insert was assessed by AC-PCR. Samples in doubt were evaluated by targeted next-generation sequencing (NGS) on MySeq (Illumina, USA). Results: In 62 out of 80 samples, the type of insert (A, B, or D) was reliably determined by AS-PCR. In 9 cases type of insert was not detected. In further 9 cases, amplification ΔCt between wild-type and mutant allele was out of reliable range. These 18 samples were examined by NGS, and 2 out of 18 showed an intron deletion, which, presumably, does not affect the function of the protein, but leads to the appearance of an additional peak on FA. In 16 out of 18 samples, non-standard inserts were detected (Table 1). Type A inserts were found in 48 out of 78 cases (61.5%), type B - in 2 out of 78 (4.5%), and type D - 15.4% (12 out of 78). We have detected atypical inserts in 16 out of 78 cases (20.5%), which is more than reported in the literature. 14 out of 16 atypical inserts result in a leucine-rich motif, as do standard inserts. In 4 out of 16 cases, one of the 2 functionally important tryptophan residues was retained (W280), therefore possibly conserving nuclear localization signal. The effect of partial preservation of the nucleolar localization of nucleophosmin on prognosis in AML has not been studied yet. Image:Summary/Conclusion: FA is still a golden standard for screening NPM1 gene mutations in AML. AS-PCR could be effectively used for monitoring cases with standard inserts. However, NGS greatly facilitates non-standard inserts identification, appropriate allele-specific primers design for MRD analysis, and avoiding false-positive FA results for cases with intron localization of the insert.

P910: DOES MINIMAL RESIDUAL DISEASE OF STEM CELL COLLECTION HAVE PROGNOSTIC IMPACT ON PATIENTS WITH MULTIPLE MYELOMA?

Background: Multiple myeloma (MM) is a kind of hematological malignancy involved in monoclonal plasma cells. In most clinical guidelines autologous stem cell transplantation (ASCT) is considered as the standard of care for transplant-eligible patients (TEMM) as long as patients achieving partial response (PR). However, it is unclear that under the circumstance of not achieving complete response (CR) weather it would lead to the presence of neoplastic plasma cells in the stem cell collection (SCC) and then result in negative impact on survival prognosis. Aims: Here, we evaluated the effect of the minimal residual disease (MRD) of SCC in the TEMM. Methods: We analyzed retrospectively clinical data of 90 patients with MM undergoing ASCT between January 1, 2013 to June 1, 2021 and MRD evaluation of both bone marrow (BM) and SCC were carried out at the same time. MRD was evaluated by multiparameter flow cytometry (MFC) with 10-4-10-5 sensitivity. The best response was defined as the deepest response during the follow-up. Here we defined the time from ASCT to disease progression or death as modified progression-free survival (mPFS) and the time from ASCT to death as modified overall survival (mOS). Results: A total of 90 patients met the inclusion criteria. The median age is 54 (37-69) and 62.2% were males. There were 25 (27.8%) patients presenting high-risk cytogenetic abnormalities by FISH, defined as the presence of at least one of t (4;14), t (14;16) or del (17p). Before ASCT 36.7% of patients achieved MRD negativity in BM and 76.7% in SCC. After the comparison among MRD-positivity status with different sensitivity and numbers of detectable MRD neoplastic plasma cells, we found that the percentage of patients with MRD positivity in SCC was much less than that in BM no matter the sensitivity (P <0.001). Neither mPFS (P=0.861, median mPFS, 40.83m vs. 34.17m for negativity vs. positivity) nor mOS (P=0.747, median mOS, 67.02m vs. 58.86m for negativity vs. positivity) was affected by MRD status in SCC. According to MRD status they were divided into 4 groups, namely MRD negativity in BM and SCC (Group A, 34.4%), MRD positivity in BM but negativity in SCC (Group B, 22.2%), MRD positivity in BM and SCC (Group C, 41.1%) as well as MRD negativity in BM but positivity in SCC (Group D, 2.3%). Having taken the inaccuracy of biopsy into consideration we excluded Group D. The median follow-up of the cohort was 26.8 months (15.1-105.1m). Patients among the three groups experienced similar mPFS (P=0.403, median mPFS, 41.07m vs. 34.17m vs. 40.83m, for Group A, B and C, respectively) and similar mOS (P=0.933, median mOS, 67.02m vs. 58.86m vs. 58.61m for Group A, B and C, respectively). Achievement of CR with the presence of MRD negativity was associated with prolonged mPFS and mOS compared with MRD-positive CR or ≤VGPR (P＜0.001, median mPFS, 55.88m vs. 23.03m vs. 27.10m, respectively; P=0.026, median mOS, 67.02 vs. 46.16m vs. 41.65m, respectively). Image:Summary/Conclusion: Our results demonstrated that neoplastic plasma cells in SCC have little impact on the survival prognosis in MM patients and it is sound to carry out ASCT when TEMM patients achieving PR. Also, MRD-negativity status can be considered more valuable on prognosis than CR.

Impact of high-dose melphalan followed by autologous stem cell transplant in producing MRD negative complete response in newly diagnosed multiple myeloma.

e20001 Background: High dose melphalan followed by autologous stem cell transplant (HDM-ASCT) remains the standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM) despite advances in treatments. Achievement of complete response (CR) is associated with improved overall survival (OS) and progression-free survival (PFS); Minimal Residual Disease (MRD) negativity (-) using next generation flow cytometry with a sensitivity of 10-5 is strongly associated with improved PFS and OS. We investigated the rates of conversion to MRD(-), especially MRD(-) CR following HDM-ASCT in patients with NDMM. Methods: We retrospectively reviewed patients with NDMM who underwent early HDM-ASCT at Mayo Clinic Rochester from May 2018 to July 2019. Response assessment was conducted after induction and within 100 days post-ASCT based on 2016 IMWG criteria, except for using Mass-Fix instead of immunofixation. MRD was assessed in bone marrow using the established Euro Flow protocol with sensitivity of 10-5. The FISH assay was used to risk-stratify patients as high-risk (HR) and standard risk (SR) cytogenetics as per the mSMART guidelines. Primary outcome measure was the conversion to MRD(-) CR after ASCT. Secondary outcomes include the overall conversion to MRD(-) irrespective of IMWG response, the impact of HR cytogenetics and pre-ASCT IMWG response on conversion to MRD(-) CR. Results: Two-hundred and ten patients were included; 126 (60%) were male and median age 62 years (range 32–77 years). There were 78 (44%) patients with HR cytogenetics. Pre-ASCT, 23 patients (11%) achieved MRD(-) CR, and 66 (31%) patients achieved MRD(-) CR post ASCT. Of 187 patients not in MRD(-) CR pre-ASCT, 45 (24%) converted to MRD(-) CR. Table provides a breakdown of the conversion rate of pre-ASCT IMWG response category to MRD(-) CR post ASCT and patients with MRD(+) CR had the highest rate (78%) of conversion. The presence of HR cytogenetics did not impact rates of MRD(-) CR achievement post ASCT irrespective of pre-ASCT IMWG response (p = 1.0). Overall, irrespective of IMWG response, 43 (20%) patients were MRD(-) pre-ASCT (19 in VGPR, 24 in CR or better) and 102 (49%) patients were MRD(-) post-ASCT (36 in VGPR, 66 in CR or better). Among 85 patients in VGPR post-ASCT, 36 were MRD(-) of which 8 (22%) progressed, while 49 were MRD(+) of which 24 (49%) progressed (p = 0.014). Conclusions: Upfront HDM-ASCT in patients with NDMM leads to deeper responses with 24% converting to MRD(-) CR and more than doubling of the total rate of MRD(-) irrespective of IMWG response. [Table: see text]

Phase II study of the combination of daratumumab, ixazomib, pomalidomide, and dexamethasone as salvage therapy in relapsed/refractory multiple myeloma: Stage 2 interim results.

8041 Background: The combination of daratumumab (Dara), pomalidomide (POM), and dexamethasone (dex) (DPd) has previously demonstrated deep and durable responses including high rates of minimal residual disease (MRD) negativity, in patients with relapsed/refractory (R/R) MM. Quadruplet regimens may further improve results. We report updated findings from a phase 2 multicenter trial of the addition of ixazomib to DPd (DIPd) in patients with early R/R MM. Methods: This is a prospective, multi-center, open-label, single arm phase II trial with a primary objective to evaluate the overall response rate (ORR), safety, and efficacy of DIPd. Secondary endpoints include progression-free survival (PFS), overall survival (OS), and MRD-negativity rate. A Simon’s optimal 2-stage design was used, with 14 subjects in stage 1 to assess response and 32 patients for stage 2. Eligible patients may not have had exposure Dara or ixazomib, may not have progressed on POM, and may have received ≥1 and ≤3 prior lines of therapy. The first six patients in the safety run-in received Dara 16mg/kg IV weekly x 8 doses, biweekly x 8 doses, then monthly, POM 4mg orally on days 1-21 of a 28-day cycle, ixazomib 4mg orally on days 1,8,15 every 28 days, and dex 20-40mg weekly. Grade 3-4 neutropenia was observed in 100% of patients, prompting dose reduction to ixazomib 3 mg and POM 3 mg by the DSMB. An amendment allowed subcutaneous Dara administration. MRD assessments are being performed by EuroFlow for patients in VGPR or suspected CR. Pharmacodynamic changes in patients’ tumor microenvironments were established by custom panel mass cytometry to include T-cell memory and activated subpopulations, B-cell content, NK-cell subpopulations as well as MDSCs, Tregs and T-exhaustive markers, monocytes and dendritic cells. Results: To date, 14 subjects have been treated in stage 1, and 18 patients in stage 2. Median age was 61.5 (range 41-87) years, 50% were female and 72% white. Median number of prior regimens was 1 (range 1-3), all patients were lenalidomide-exposed, and 47% (11/23) had high-risk cytogenetic features. The most common grade 3-4 treatment emergent adverse events included neutropenia (78%), infection (30%), leukopenia (11%), respiratory conditions (7%), psychiatric disturbance (4%), and thrombosis (4%). Median time on treatment was 4 months (1-29), with 11 patients remaining on DIPd and 5 deaths (4 due to progressive disease and 1 due to sepsis). ORR to date was 84% (16/19), and the best responses included: 5 (26%) sCR; 4 (21%) VGPR; 7 (37%) PR. After a median follow up of 12 months, the median OS was 39 months and PFS was 9.5 months. Conclusions: The quadruplet regimen DIPd is a well-tolerated combination that has shown early safety, efficacy, and ORR in early R/R myeloma, including patients with high-risk genetic abnormalities. Clinical trial information: NCT03590652.

Comparison of the Early Efficacy and Serious Adverse Events between CCCG-ALL 2015 and CCLG-ALL 2008 in the Treatment of Pediatric Patients with Acute Lymphoblastic Leukemia

To evaluate the early efficacy and serious adverse events (SAE) related to chemotherapy of different protocols in the treatment of pediatric patients with acute lymphoblastic leukemia (ALL), so as to improve the overall survival rate. A comparison of the early efficacy and SAE was performed between pediatric patients treated with Chinese Children Cancer Group-ALL 2015 (CCCG-ALL 2015) protocol from January 2019 to June 2020 and those treated with Chinese Children Leukemia Group-ALL 2008 (CCLG-ALL 2008) protocol from January 2017 to December 2018. The remission rate before consolidation chemotherapy between the two groups was not significantly different (P=0.198), but the negative conversion rate of minimal residual disease (MRD) in CCLG-ALL 2008 group was significantly higher than that in CCCG-ALL 2015 group (P=0.000). The incidence of SAE in CCCG-ALL 2015 group was significantly lower than that in CCLG-ALL 2008 group (P=0.021), and the incidence of infection-related SAE was significantly higher in the latter (P=0.001), while the difference of non-infection-related SAE was not statistically significant (P=0.623). In addition, the treatment-related mortality in CCCG-ALL 2015 group was significantly lower than that in CCLG-ALL 2008 group (P=0.003). CCCG-ALL 2015 regimen reduces the intensity of chemotherapy, which can significantly decrease the chemotherapy-related SAE (especially infection-related SAE), as well as treatment-related mortality. However, the MRD negative conversion rate is low before consolidation treatment, and the overall long-term efficacy remains to be further observed.

B-PRISM (Precision Intervention Smoldering Myeloma): A phase II trial of combination of daratumumab, bortezomib, lenalidomide, and dexamethasone in high-risk smoldering multiple myeloma.

8040 Background: Early therapeutic intervention with lenalidomide has shown to be effective in delaying progression in patients with high-risk smoldering multiple myeloma (HR-SMM) (Lonial J Clin Oncol 2020). Quadruplet regimen of daratumumab, bortezomib, lenalidomide and dexamethasone (D-RVD) has demonstrated significant activity in multiple myeloma, achieving high rates of minimal residual disease (MRD) negativity (Voorhees Blood 2020). Thus, we proposed to examine the activity and safety of D-RVD in patients with HR-SMM. Methods: This is a phase II single center, single-arm, open label study evaluating the combination of D-RVD in HR-SMM. Eligibility included high risk per Mayo 2018 “20-2-20” model and other previously established criteria including Mayo 2008 criteria, presence of immunoparesis, evolving type of SMM, and high risk FISH. Primary objective is rate of sustained MRD negativity at 2 years. Secondary objectives include PFS, response rates and safety. Treatment duration with modified D-RVD is for total of 2 years (24 cycles). Daratumumab is administered subcutaneously (SQ) per standard dose and schedule, bortezomib given weekly on days 1, 8, 15 for cycles 1-6 and then biweekly until completion of cycle 24. Lenalidomide is administered on days 1-21 and dexamethasone is administered weekly. All eligible patients will undergo stem cell collection after 6 cycles of therapy. Results: At the time of data cut off, 20 patients have been enrolled with a median follow up of 6 months. The median age is 58 years old (range 40-73). Sixteen out of 20 (80%) patients met high risk criteria per Mayo 2018 model with median plasmacytosis of 20%, median M protein value of 2.6 g/dl and median FLC ratio of 28.2. Seven patients had high-risk FISH: 5 with 1q duplication, 2 with t(4;14). Most common toxicities of any grade included neutropenia (65%), WBC decreased (55%) insomnia (50%), constipation (45%) and hypophosphatemia (45%). Most common grade 3 toxicities included neutropenia (15%), ALT increased (5%), thrombocytopenia (5%), hyperglycemia (5%), hypertension (5%), diarrhea (5%), syncope (5%). No patients discontinued therapy due to toxicity. The overall response rate is 90% with 40% PR, 25% VGPR and 25% CR. All patients have achieved at least a MR and 50% achieved VGPR or greater with responses deepening over time. No patients have progressed on treatment. MRD was evaluable in 16 patients and 8 patients have undergone MRD testing, with MRD negativity rate of 50% (4/8) and 25% (2/8) at thresholds of 10-5 and 10-6, respectively. Stem cells were successfully collected in all patients with mean stem cell yield of 5.78 x 106 CD34+/kg cells. Conclusions: D-RVD is well tolerated in patients with HR-SMM demonstrating significant early activity. Responses continue to deepen over time with patients achieving MRD negative disease. Clinical trial information: NCT04775550.

Daratumumab in first-line therapy is cost-effective in transplant-eligible patients with newly diagnosed myeloma

AbstractTriplet regimens, such as lenalidomide, bortezomib, and dexamethasone (RVd) or thalidomide, bortezomib, and dexamethasone (VTd), are standard induction therapies for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab to RVd and VTd has been investigated in the GRIFFIN and CASSIOPEIA trials, respectively, resulting in improvement in the rate of minimal residual disease (MRD) negativity. In this study, we conducted a cost-effectiveness analysis with a 10-year time horizon to compare first-line and second-line use of daratumumab for transplant-eligible patients with NDMM. Because long-term follow-up data for these clinical trials are not yet available, we developed a Markov model that uses MRD status to predict progression-free survival. Daratumumab was used either in the first-line setting in combination with RVd or VTd or in the second-line setting with carfilzomib plus dexamethasone (Kd). Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios were calculated from a Japanese and US payer perspective. In the Japanese analysis, D-RVd showed higher QALYs (5.43 vs 5.18) and lower costs (¥64 479,793 vs ¥71 287 569) compared with RVd, and D-VTd showed higher QALYs (5.67 vs 5.42) and lower costs (¥43 600 310 vs ¥49 471,941) compared with VTd. Similarly, the US analysis demonstrated dominance of a strategy incorporating daratumumab in first-line treatment regimens. Given that overall costs are reduced and outcomes are improved when daratumumab is used as part of a first-line regimen, the economic analysis indicates that addition of daratumumab to first-line RVd and VTd regimens is a dominant strategy compared with reserving its use for the second-line setting.

Guideline for the treatment of chronic lymphocytic leukaemia

Guideline for the treatment of chronic lymphocytic leukaemia

What Is the Role of HSCT in Philadelphia-Chromosome-Positive and Philadelphia-Chromosome-Like ALL in the Tyrosine Kinase Inhibitor Era?

Previously, the outcome of paediatric Philadelphia-chromosome–positive (Ph+) ALL treated with conventional chemotherapy alone was poor, necessitating the use of haematopoietic stem cell transplantation (HSCT) for the best outcomes. The recent addition of tyrosine kinase inhibitors (TKIs) alongside the chemotherapy regimens for Ph+ ALL has markedly improved outcomes, replacing the need for HSCT for lower risk patients. An additional poor prognosis group of Philadelphia-chromosome–like (Ph-like) ALL has also been identified. This group also can be targeted by TKIs in combination with chemotherapy, but the role of HSCT in this population is not clear. The impact of novel targeted immunotherapies (chimeric antigen receptor T cells and bispecific or drug-conjugated antibodies) has improved the outcome of patients, in combination with chemotherapy, and made the role of HSCT as the optimal curative therapy for Ph+ ALL and Ph-like ALL less clear. The prognosis of patients with Ph+ ALL and persistent minimal residual disease (MRD) at the end of consolidation despite TKI therapy or with additional genetic risk factors remains inferior when HSCT is not used. For such high-risk patients, HSCT using total-body-irradiation–containing conditioning is currently recommended. This review aims to provide an update on the current and future role of HSCT for Ph+ ALL and addresses key questions related to the management of these patients, including the role of HSCT in first complete remission, MRD evaluation and related actions post HSCT, TKI usage post HSCT, and the putative role of HSCT in Ph-like ALL.

Utility of Cell-Free DNA Detection in Transplant Oncology.

Simple SummaryTransplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-liver transplant stages, and evaluate transplant rejection. The use of ctDNA to evaluate transplant rejection has been extensively studied in non-hepatocellular carcinoma (HCC) diseases. Emerging studies have also investigated the use of ctDNA detection in evaluating HCC tumor burden pre-and post-surgery as well as transplant rejection. However, extensive studies still need to be conducted to evaluate the role of ctDNA detection in the medical management of transplant oncology patients.Transplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. A critical concept that must be addressed to ensure the successful application of transplant oncology to patient care is efficient monitoring of tumor burden pre-and post-transplant and transplant rejection. Cell-free DNA (cfDNA) detection has emerged as a vital tool in revolutionizing the management of cancer patients who undergo organ transplantation. The advances in cfDNA technology have provided options to perform a pre-transplant evaluation of minimal residual disease (MRD) and post-transplant evaluation of cancer recurrence and transplant rejection. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-transplant stages, and evaluate transplant rejection.

Is Circulating DNA and Tumor Cells in Myeloma the Way Forward?

Multiple myeloma (MM) is the second deadliest hematological cancer. Despite the enormous innovation on MM treatment in the last decades, still 48% of patients die within 5 years after diagnosis. MM diagnosis and therapeutic strategy mainly rely on direct bone marrow (BM) assessment. Given the MM heterogeneity, BM biopsies do not accurately reflect the whole disease status, hampering accurate disease prognosis. Moreover, biopsies are painful and invasive procedures, highlighting the need for non-invasive and more accurate source of biomarkers. Liquid biopsies are promising sources of biomarkers that may overcome these limitations. Peripheral blood carries circulating myeloma components that are being extensively explored since the last few years as an alternative to BM aspirates. These include circulating tumor cells (CTC), cell-free DNA (cfDNA), and extracellular vesicles containing miRNA and proteins. The current review summarizes scientific evidence establishing BM as a gold standard for the diagnosis, prognosis, and evaluation of minimal residual disease. We discuss the last advances regarding cfDNA and CTC biomarkers from peripheral blood in patients with MM as well as the statistical validations. This paper addresses the technological hurdles associated with liquid biopsies and examines the missing steps for their inclusion into the clinical practice.

Preemptive Immunotherapy for Minimal Residual Disease in Patients With t(8;21) Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation.

In patients with t(8;21) acute myeloid leukemia (AML), recurrent minimal residual disease (MRD) measured by RUNX1-RUNX1T1 transcript levels can predict relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed to compare the efficacy of preemptive interferon (IFN)-α therapy and donor lymphocyte infusion (DLI) in patients with t(8;21) AML following allo-HSCT. We also evaluated the appropriate method for patients with different levels of RUNX1-RUNX1T1 transcripts. In this retrospective study, consecutive patients who had high-risk t(8;21) AML and received allo-HSCT were enrolled. The inclusion criteria were as follows: (1) age ≤65 years; (2) regained MRD positive following allo-HSCT. MRD positive was defined as the loss of a ≥4.5-log reduction and/or <4.5-log reduction in the RUNX1-RUNX1T1 transcripts, and high-level, intermediate-level, and low-level MRDs were, respectively, defined as <2.5-log, 2.5−3.5-log, and 3.5−4.5-log reductions in the transcripts compared with the pretreatment baseline level. Patients with positive RUNX1-RUNX1T1 could receive preemptive IFN-α therapy or DLI, which was primarily based on donor availability and the intentions of physicians and patients. The patients received recombinant human IFN-α-2b therapy by subcutaneous injection twice a week every 4 weeks. IFN-α therapy was scheduled for six cycles or until the RUNX1-RUNX1T1 transcripts were negative for at least two consecutive tests. The rates of MRD turning negative for patients with low-level, intermediate-level, and high-level RUNX1-RUNX1T1 receiving IFN-α were 87.5%, 58.1%, and 22.2%, respectively; meanwhile, for patients with intermediate-level and high-level RUNX1-RUNX1T1 receiving DLI, the rates were 50.0% and 14.3%, respectively. For patients with low-level and intermediate-level RUNX1-RUNX1T1, the probability of overall survival at 2 years was higher in the IFN-α group than in the DLI group (87.6% vs. 55.6%; p = 0.003). For patients with high levels of RUNX1-RUNX1T1, the probability of overall survival was comparable between the IFN-α and DLI groups (53.3% vs. 83.3%; p = 0.780). Therefore, patients with low-level and intermediate-level RUNX1-RUNX1T1 could benefit more from preemptive IFN-α therapy compared with DLI. Clinical outcomes were comparable between preemptive IFN-α therapy and DLI in patients with high-level RUNX1-RUNX1T1; however, they should be further improved.

Evaluation of minimal residual disease by flowcytometry and its clinicopathological correlation in B-lineage acute lymphoblastic leukemia in a tertiary care centre

Evaluation of minimal residual disease by flowcytometry and its clinicopathological correlation in B-lineage acute lymphoblastic leukemia in a tertiary care centre

Use of Circulating Tumour DNA to Assess Minimal Residual Disease in Gastrointestinal Cancers

Despite our modern perioperative therapies, many patients with gastrointestinal cancer relapse after surgery. Novel strategies to identify and treat patients at high risk of relapse are needed to improve cancer outcomes. Circulating tumour DNA (ctDNA) is a promising, non-invasive biomarker with the potential to identify the earliest signs of cancer relapse. The presence of tumourspecific DNA in the blood in the absence of visualized tumour is suggestive of minimal residual disease and forebodes measurable relapse. Genomic sequencing techniques have advanced over the past few decades, and we have become better able to detect significantly low levels of DNA circulating in the blood from low-volume disease. Numerous studies using various technologies have established ctDNA as a powerful prognostic biomarker for relapse and survival in gastrointestinal cancers. ctDNA has the potential to risk-stratify patients in the postoperative, post-adjuvant and longitudinal settings for therapeutic escalation or de-escalation strategies. It may also capture early tumour dynamics in response to therapeutic intervention. As the multifaceted potential of ctDNA is attracting the attention of researchers, clinicians and patients, many questions remain regarding its use, interpretation and limitations. Here, we discuss the current understanding of ctDNA for minimal residual disease evaluation in gastrointestinal cancers and potential future directions.

MRD in adult Ph/BCR-ABL-negative ALL: how best to eradicate?

Evaluation of minimal residual disease (MRD) during first-line treatment and after salvage therapy is part of the standard management of acute lymphoblastic leukemia (ALL). Persistent or recurrent MRD is one of the most relevant prognostic factors and identifies a group of patients with resistance to standard chemotherapy. These patients have a high risk of relapse despite continued first-line therapy. Although stem cell transplantation (SCT) is an appropriate strategy, patients with high MRD show an increased relapse rate even after SCT. Approximately one-quarter of adult ALL patients develop an MRD failure, defined as MRD above 0.01% after standard induction and consolidation. The best time point and level of MRD for treatment modification are matters of debate. In order to eradicate MRD and thereby improve chances for a cure, new targeted compounds with different mechanisms of action compared to chemotherapy are being utilized. These compounds include monoclonal antibodies, chimeric antigen receptor T cells, and molecular targeted compounds. Essential factors for decision-making, available compounds, and follow-up therapies are discussed.

Molecular and MRD-Based Characterization of Acute Lymphoblastic Leukemia in Mexico: Experience from the Mexico in Alliance with St. Jude “Bridge Project”

▪Background: Cancer is the second leading cause of death in Mexico among children 5-14 years. In 2017, Mexico in Alliance with St. Jude (MAS), a multi-site intersectoral collaboration, explored reasons for suboptimal outcomes for children with acute lymphoblastic leukemia (ALL). Results showed 82% of patients to be classified as high-risk and 30% of patients be missing standard molecular or minimal residual disease (MRD) studies needed to inform risk- group stratification. Making sense of the molecular characteristics was challenging in the context of variable access and lack of common denominators. These findings led to the development of the “Bridge Project”; a prospective quality improvement demonstration project aiming to bridge this access and quality gap through multi-site collaboration, centralization, and standardization.Methods: Six MAS collaborating hospitals, located in six different states (Mérida, Guadalajara, Sinaloa, Baja California, Chiapas, and Veracruz), have sent diagnostic samples for children 0-18 years old with suspected ALL to Hospital Infantil Teletón de Oncología (HITO), in Queretaro, which serves as the centralized laboratory for the MAS cooperative group. Access to the diagnostic panel is secured upfront through dedicated funding obtained from a local foundation. The first sample was shipped in July 2019. The consensus-derived diagnostic panel includes morphology, immunophenotype, karyotype, fluorescent in situ hybridization (FISH), molecular biology (RT-PCR) and flow cytometry (FC) MRD at two time points. Protocols vary by institution and MRD evaluation is only done if the institutional protocol incorporates MRD-evaluation into the risk-group stratification. Hospitals send several empty boxes prior to shipping patient samples to assess their regional shipping vendors and timelines. The also standardize data collection processes and use PDSA cycles to monitor sample quality and address issues with sample quality. HITO produces FC results (for diagnosis or MRD evaluation) and FISH/cytogenetic results within 3 to 21 days of sample arrival.Results: As of July 2021, the centralized lab has received samples from 217 patients with suspected ALL through this project and 93% of these samples have arrived within the 48hr target. Of these, 176 (81.1%) had confirmed ALL and 14 (6.4%) had acute myeloid leukemia (AML), 2 (0.9%) cases had other malignant conditions, and in 25 (11.5%) of the cases leukemia was ruled out. Among the 176 cases of confirmed ALL, 162 (92%) had B-cell lineage and 14 (8%) had T-cell lineage. FISH was reported for 172 (97.7%) patients and positive in 126 (73.2%) cases; 46 (26.7%) cases had reported gains, 34 (19.7%) detected t(12;21), 18 (10.4%) detected iAMP cr21, 8 (4.7%) detected breaks of the MLL gene t(4;11), 7 (4%) detected t(1;19), and 6 (3.4%) detected t(9;22). Four T-cell ALL cases had breaks CDKN2A del(9)(p21) and three cases had TRA/D rearrangement (14) (q11.2). Karyotype alterations were detected in 90 (52.3%) of the samples, of which 41 (23.8%) showed hyperdiploidy and 13 (7%) showed complex karyotype. One case of hypodiploid was identified. Day 15 MRD was assessed in 131 (80%) patients with B-cell lineage, Day 84 MRD was assessed in 99 (61.1%) patients with B-cell lineage, and Day 29 MRD in 8 (57.1%) patients with T-cell lineage whose treatment schema utilizes MRD-based stratification. Among B-lineage patients, 84% had MRD <1% at Day 15 and 94.9% MRD <0.01% at Day 84. Among T-cell lineage patients, 75% had MRD <0.01% at Day 29 and 80% MRD <0.01% at Day 84, but numbers for T-cell lineage were small.Conclusions: Given proper structural and financial supports, patients with suspected childhood ALL in Mexico can access a comprehensive diagnostic panel following a centralized laboratory approach. Preliminary results from the Bridge Project allow characterizing childhood ALL to a degree that has not been previously possible in Mexico. In this cohort, favorable characteristics such a t(12;21), gains, and hyperdiploidy are observed in frequencies similar to those reported in Hispanic cohorts in high-income countries. MRD results are for B-cell lineage are also consistent with the literature. Continued engagement in this project from hospitals in diverse geographic settings and with diverse patient populations will allow the MAS cooperative group to continue to improve the characterization of childhood ALL in Mexico. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Prognostic Impact of Minimal Residual Disease Assessment in Elderly Patients with Secondary Acute Myeloid Leukemia. a Comparison between CPX-351 and Intensified Fludarabine-Based Regimens

Background: Minimal residual disease (MRD) assessment retains high prognostic value in Acute Myeloid Leukemia patients (AML) undergoing intensive induction therapy. Widely available MRD techniques include multicolour flow cytometry (MFC), RT-PCR for recurrent genetic lesion and, for patients lacking specific markers, RT-PCR for the pan- leukemic marker WT1. However, most of the data on the prognostic value of MRD come from trials including younger patients treated with conventional 3+7 regimen. AML arising from a previous myelodisplastic syndrome (s-AML) and therapy-related AML (t-AML) are usually under-represented in trial involving younger patients and are unlikely to respond to conventional induction. Few data are therefore available on the kinetics and the prognostic value of MRD in elderly s- AML and t-AML patients, particularly in the context of alternative induction regimens.Aims: We evaluated MRD in a cohort of elderly s-AML or t-AML patients receiving induction therapy either with a fludarabine-containing regimen or CPX-351, in order to compare the probability of achieving MRD negativity, to disclose the prognostic value of MRD in this setting and to define the best time-points for MRD assessments.Methods: A total of 136 elderly (>60 year, median age 67, range 60-75) patients were analyzed in this study. Patients were treated between January 2005 and January 2020 in our Center, either with CPX-351 (n=35) or fludarabine- high dose cytarabine-idarubicin (FLAI), with (n=72) or without (n =29) gemtuzumab-ozogamicin (GO). MRD was retrospectively analyzed in all patients achieving hematological complete remission (CR) with both MFC and WT1 expression levels.All patients were affected by s-AML or t-AML, defined according to the WHO 2016 criteria.Results: After induction, CR was achieved in 83 patients (61%). CR rate was 28/35 in patients treated with CPX-351 (80%), significantly higher when compared to patients receiving FLAI (55/101, 54.5%, p<0.05). The addition of GO to FLAI did not increase CR rate. Among CR patients, a total of 41 (49.4%) and 44 patients (53%) achieved MRD negativity, with MFC or WT1-based methods, respectively. MFC MRD negativity probability was higher among patients receiving CPX-351 as induction therapy (MFC MRD negativity rate of 16/28, 57% and 25/55, 45% in CR patients who received CPX-351 or FLAI, respectively, p<0.05). Adding GO to FLAI did not improve MRD negativity probability.Moreover, MRD showed significant prognostic value in terms of Overall Survival in all treatment group (2-year OS of 74 and 36% in patients with or without residual MFC MRD after induction, respectively, p<0.05). WT1-based MRD lead to similar results.Conclusion: In conclusion MRD assessment retains a strong prognostic value and may help to identify patients with suboptimal response to treatment. The higher rate of MRD negativity observed with CPX-351 may be related with a more efficient anti-leukemic activity of the drug in this particular setting. The evaluation of MRD with both MFC and WT1-based assessment lead to superimposable conclusions and allowed us to obtain MRD data from virtually all AML patients treated in the selected time period. DisclosuresNo relevant conflicts of interest to declare.

A Prospective Phase I/II Trial to Jointly Optimize the Administration Schedule and Dose of Melphalan for Injection (Evomela) As a Preparative Regimen for Autologous Hematopoietic Stem Cell Transplantation in Newly Diagnosed Multiple Myeloma

A Prospective Phase I/II Trial to Jointly Optimize the Administration Schedule and Dose of Melphalan for Injection (Evomela) As a Preparative Regimen for Autologous Hematopoietic Stem Cell Transplantation in Newly Diagnosed Multiple Myeloma

Trial in Progress: A Phase 2 Single Arm, Multicenter Trial to Evaluate the Efficacy of the BiTE ® Antibody Blinatumomab (Blincyto) and Vincristine Sulfate Liposomal Injection (Marqibo) in Adult Subjects with Relapsed/Refractory Philadelphia Negative CD19+ Acute Lymphoblastic Leukemia

Trial in Progress: A Phase 2 Single Arm, Multicenter Trial to Evaluate the Efficacy of the BiTE ® Antibody Blinatumomab (Blincyto) and Vincristine Sulfate Liposomal Injection (Marqibo) in Adult Subjects with Relapsed/Refractory Philadelphia Negative CD19+ Acute Lymphoblastic Leukemia