Chimeric Antigens Receptor T Cell Therapy Improve the Prognosis of Pediatric Acute Lymphoblastic Leukemia With Persistent/Recurrent Minimal Residual Disease in First Complete Remission

BackgroundThe presence of minimal residual disease (MRD) is an independent risk factor for poor prognosis in patients with acute lymphoblastic leukemia (ALL). Moreover, the role of chimeric antigen receptor T-cell (CAR-T) therapy in patients with MRD is currently unclear.MethodsWe conducted a prospective study to investigate the role of CAR-T therapy in patients with persistent/recurrent MRD-positive ALL in first remission.ResultsA total of 77 patients who had persistent/recurrent MRD were included. Of these patients, 43 were enrolled in the CAR-T group, 20 received chemotherapy as a bridge to allogeneic hematopoietic cell transplantation (allo-HSCT), and 14 patients received intensified chemotherapy. MRD negativity was achieved in 90.7% of the patients after CAR-T infusion. Patients who received CAR-T therapy had a higher 3-year leukemia-free survival (LFS) than patients who did not (77.8% vs. 51.1%, P = 0.033). Furthermore, patients in the CAR-T group had a higher 3-year LFS than those in the chemotherapy bridge-to-allo-HSCT group [77.8% (95% CI, 64.8–90.7%) vs. 68.7% (95% CI, 47.7–89.6%), P = 0.575] and had a significantly higher 3-year LFS than those in the intensified chemotherapy group [77.8% (95% CI, 64.8–90.7%) vs. 28.6% (95% CI, 4.9–52.3%), P = 0.001]. Among the patients who received CAR-T therapy, eight were not bridged to allo-HSCT, and six (75%) remained in remission with a median follow-up of 23.0 months after CAR-T infusion.ConclusionsOur findings show that CAR-T therapy can effectively eliminate MRD and improve survival in patients with a suboptimal MRD response.

Monitoring of post-transplant MLL-PTD as minimal residual disease can predict relapse after allogeneic HSCT in patients with acute myeloid leukemia and myelodysplastic syndrome

Background The mixed-lineage leukemia (MLL) gene is located on chromosome 11q23. The MLL gene can be rearranged to generate partial tandem duplications (MLL-PTD), which occurs in about 5-10% of acute myeloid leukemia (AML) with a normal karyotype and in 5-6% of myelodysplastic syndrome (MDS) patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently one of the curative therapies available for AML and MDS with excess blasts (MDS-EB). However, how the prognosis of patients with high levels of MLL-PTD after allo-HSCT, and whether MLL-PTD could be used as a reliable indicator for minimal residual disease (MRD) monitoring in transplant patients remains unknown. Our study purposed to analyze the dynamic changes of MLL-PTD peri-transplantation and the best threshold for predicting relapse after transplantation. Methods We retrospectively collected the clinical data of 48 patients with MLL-PTD AML or MDS-EB who underwent allo-HSCT in Peking University People’s Hospital. The MLL-PTD was examined by real-time quantitative polymerase chain reaction (RQ-PCR) at the diagnosis, before transplantation and the fixed time points after transplantation. Detectable MLL-PTD/ABL > 0.08% was defined as MLL-PTD positive in this study. Results The 48 patients included 33 AML patients and 15 MDS-EB patients. The median follow-up time was 26(0.7-56) months after HSCT. In AML patients, 7 patients (21.2%) died of treatment-related mortality (TRM), 6 patients (18.2%) underwent hematological relapse and died ultimately. Of the 15 patients with MDS-EB, 2 patients (13.3%) died of infection. The 3-year cumulative incidence of relapse (CIR), overall survival (OS), disease-free survival (DFS) and TRM were 13.7 ± 5.2, 67.8 ± 6.9, 68.1 ± 6.8 and 20.3% ± 6.1%, respectively. ROC curve showed that post-transplant MLL-PTD ≥ 1.0% was the optimal cut-off value for predicting hematological relapse after allo-HSCT. There was statistical difference between post-transplant MLL-PTD ≥ 1.0% and MLL-PTD < 1.0% groups (3-year CIR: 75% ± 15.3% vs. 0%, P < 0.001; 3-year OS: 25.0 ± 15.3% vs. 80.7% ± 6.6%, P < 0.001; 3-year DFS: 25.0 ± 15.3% vs. 80.7 ± 6.6%, P < 0.001; 3-year TRM: 0 vs. 19.3 ± 6.6%, P = 0.277). However, whether MLL-PTD ≥ 1% or MLL-PTD < 1% before transplantation has no significant difference on the prognosis. Conclusions Our study indicated that MLL-PTD had a certain stability and could effectively reflect the change of tumor burden. The expression level of MLL-PTD after transplantation can serve as an effective indicator for predicting relapse.

NGS Analysis of Clonality and Minimal Residual Disease in a Patient with Concurrent Richter’s Transformation and CLL/SLL

B-cell lymphomas are neoplastic proliferations of clonal B lymphocytes. Clonality is generally determined by PCR amplification of VDJ rearrangements in the IgH heavy chain or VJ rearrangements in Igκ/Igλ light chain genes followed by capillary electrophoresis. More recently, next-generation sequencing (NGS) has been used to detect clonality in B-cell lymphomas because of the exponential amount of information that is obtained beyond just detecting a clonal population. The additional information obtained is useful for diagnostic confirmation, prognosis assessment, and response to therapy. In this study, we utilized NGS analysis to characterize two histologically distinct lymphomas (DLBCL and CLL/SLL) that were detected contemporaneously in an asymptomatic patient. NGS analysis showed that the same VDJ rearrangement was present in nodal (DLBCL) and marrow (CLL/SLL) biopsies confirming that the DLBCL resulted from Richter’s transformation of a subclinical CLL/SLL. The V region of the rearrangement remained unmutated without somatic hypermutation. In silico analysis showed that the HCDR3 sequence was heterogeneous and not stereotypic. Minimal residual disease analysis by NGS showed that the tumor clone decreased by 2.84 logs in the bone marrow after R-CHOP therapy. However, a small number of tumor cells were still detected in the peripheral blood after R-CHOP therapy. Subsequent allogeneic transplantation was successful in eradicating the tumor clone and achieving deep molecular remission. We show that NGS analysis facilitated clinical management in our patient by helping to characterize the VDJ rearrangement in detail and by tracking minimal residual disease with high sensitivity and specificity.

Daratumumab, Carfilzomib, Lenalidomide, and Dexamethasone With Minimal Residual Disease Response-Adapted Therapy in Newly Diagnosed Multiple Myeloma

PURPOSE The MASTER trial combined daratumumab, carfilzomib, lenalidomide, and dexamethasone (Dara-KRd) in newly diagnosed multiple myeloma (NDMM), using minimal residual disease (MRD) by next-generation sequencing (NGS) to inform the use and duration of Dara-KRd post-autologous hematopoietic cell transplantation (AHCT) and treatment cessation in patients with two consecutive MRD-negative assessments. METHODS This multicenter, single-arm, phase II trial enrolled patients with NDMM with planed enrichment for high-risk cytogenetic abnormalities (HRCAs). Patients received Dara-KRd induction, AHCT, and Dara-KRd consolidation, according to MRD status. MRD was evaluated by NGS at the end of induction, post-AHCT, and every four cycles (maximum of eight cycles) of consolidation. Primary end point was achievement of MRD negativity (< 10–5). Patients with two consecutive MRD-negative assessments entered treatment-free MRD surveillance. RESULTS Among 123 participants, 43% had none, 37% had 1, and 20% had 2+ HRCA. Median age was 60 years (range, 36-79 years), and 96% had MRD trackable by NGS. Median follow-up was 25.1 months. Overall, 80% of patients reached MRD negativity (78%, 82%, and 79% for patients with 0, 1, and 2+ HRCA, respectively), 66% reached MRD < 10–6, and 71% reached two consecutive MRD-negative assessments during therapy, entering treatment-free surveillance. Two-year progression-free survival was 87% (91%, 97%, and 58% for patients with 0, 1, and 2+ HRCA, respectively). Cumulative incidence of MRD resurgence or progression 12 months after cessation of therapy was 4%, 0%, and 27% for patients with 0, 1, or 2+ HRCA, respectively. Most common serious adverse events were pneumonia (6%) and venous thromboembolism (3%). CONCLUSION Dara-KRd, AHCT, and MRD response-adapted consolidation leads to high rate of MRD negativity in NDMM. For patients with 0 or 1 HRCA, this strategy creates the opportunity of MRD surveillance as an alternative to indefinite maintenance.

Minimal residual disease in multiple myeloma: why, when, where

Improvements in multiple myeloma therapy have led to deeper responses that are beyond the limit of detection by historical immunohistochemistry and conventional flow cytometry in bone marrow samples. In parallel, more sensitive techniques for assessing minimal residual disease (MRD) through next-generation flow cytometry and sequencing have been developed and are now routinely available. Deep responses when measured by these assays correspond with improved outcomes and survival. We review the data supporting MRD testing as well as its limitations and how it may fit in with current and future clinical practice.