Indications for allogeneic hematopoietic cell transplantation for adults with Philadelphia-chromosome negative acute lymphoblastic leukemia in first complete remission: all about MRD?

Anti-CD19 CAR T-cell consolidation therapy combined with CD19+ feeding T cells and TKI for Ph+ acute lymphoblastic leukemia

We conducted a single-arm, open-label, single-center phase 1 study to assess the safety and efficacy of multicycle-sequential anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in combination with autologous CD19+ feeding T cells (FTCs) and tyrosine kinase inhibitor (TKI) as consolidation therapy in patients under the age of 65 years with de novo Ph-positive CD19+ B-cell acute lymphoblastic leukemia. Participants were given induction chemotherapy as well as systemic chemotherapy with TKI. Afterward, they received a single cycle of CD19 CAR T-cell infusion and another 3 cycles of CD19 CAR T-cell and CD19+ FTC infusions, followed by TKI as consolidation therapy. CD19+ FTCs were given at 3 different doses. The phase 1 results of the first 15 patients, including 2 withdrawals, are presented. The most common adverse events were cytopenia (13/13) and hypogammaglobinemia (12/13). There was no incidence of cytokine release syndrome above grade 2 or immune effector cell-associated neurotoxicity syndrome or grade 4 nonhematological toxicities. All 13 patients achieved complete remission, including 12 patients with a complete molecular response (CMR) at the data cutoff. The relapse-free survival was 84%, and the overall survival was 83% with a median follow-up of 27 months. The total number of CD19-expressing cells decreased with an increasing CMR rate. CD19 CAR T cells survived for up to 40 months, whereas CD19+ FTCs vanished in 8 patients 3 months after the last infusion. These findings could form the basis for the development of an allo-HSCT-free consolidation paradigm. This trial was registered at www.clinicaltrials.gov as #NCT03984968.

Comparable outcomes in patients with B-cell acute lymphoblastic leukemia receiving haploidentical hematopoietic stem cell transplantation: Pretransplant minimal residual disease-negative complete remission following chimeric antigen receptor T-cell therapy versus chemotherapy

Introduction

Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy followed by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) markedly improves the long-term survival of patients with refractory/relapsed (R/R) B-cell acute lymphoblastic leukemia (B-ALL).

Methods

We performed a parallel comparison of transplant outcomes in 168 B-ALL patients undergoing haplo-HSCT after achieving minimal residual disease (MRD)-negative complete remission (CR) from CAR-T therapy (n = 28) or chemotherapy (n = 140) between January 2016 and August 2021. We further divided the chemotherapy group into the first CR group (chemo+CR1, n = 118) and a second or more CR group (chemo+≥CR2, n = 22).

Results

With a median follow-up period of 31.0 months, the 2-year overall survival (OS), leukemia-free survival (LFS), non-relapse mortality (NRM), and relapse rates in the CAR-T and chemotherapy groups did not differ significantly (OS, 87.9% vs. 71.5 %; LFS, 72.0% vs. 66.8%; NRM, 3.9% vs. 13.7%; relapse, 24.1% vs. 19.4%). Multivariate analysis confirmed that ≥CR2 at transplantation following chemotherapy was an independent risk factor associated with poor OS (hazard ratio (HR) 4.22 [95% CI, 1.34–13.293], p = 0.014) and LFS (HR 2.57 [95% CI, 1.041–6.343], p = 0.041). The probabilities of OS and LFS at 2 years in the CAR-T group were comparable to those in the chemo+CR1 group but significantly higher than those in the chemo+≥CR2 group (OS, 87.9% vs. 37.8%, p = 0.007; LFS, 72.0% vs. 41.7%, p = 0.043). No significant differences in the incidences of NRM were noted among the three groups.

Conclusions

Our results demonstrated that patients with R/R B-ALL receiving haplo-HSCT after CAR-T therapy achieved comparable outcomes to patients transplanted post-chemotherapy-based MRD-negative CR1, without increased risk of transplant-related mortality and toxicity.

An Aggregated-Based Deep Learning Method for Leukemic B-lymphoblast Classification

Leukemia is a cancer of blood cells in the bone marrow that affects both children and adolescents. The rapid growth of unusual lymphocyte cells leads to bone marrow failure, which may slow down the production of new blood cells, and hence increases patient morbidity and mortality. Age is a crucial clinical factor in leukemia diagnosis, since if leukemia is diagnosed in the early stages, it is highly curable. Incidence is increasing globally, as around 412,000 people worldwide are likely to be diagnosed with some type of leukemia, of which acute lymphoblastic leukemia accounts for approximately 12% of all leukemia cases worldwide. Thus, the reliable and accurate detection of normal and malignant cells is of major interest. Automatic detection with computer-aided diagnosis (CAD) models can assist medics, and can be beneficial for the early detection of leukemia. In this paper, a single center study, we aimed to build an aggregated deep learning model for Leukemic B-lymphoblast classification. To make a reliable and accurate deep learner, data augmentation techniques were applied to tackle the limited dataset size, and a transfer learning strategy was employed to accelerate the learning process, and further improve the performance of the proposed network. The results show that our proposed approach was able to fuse features extracted from the best deep learning models, and outperformed individual networks with a test accuracy of 96.58% in Leukemic B-lymphoblast diagnosis.

Measurable residual disease of acute lymphoblastic leukemia in allograft settings: how to evaluate and intervene

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a curable strategy for acute lymphoblastic leukemia (ALL), especially for adult cases. However, leukemia relapse after allograft restricts the improvement of transplant outcomes. Measurable residual disease (MRD) has been the strongest predictor for relapse after allo-HSCT, allowing MRD-directed preemptive therapy.

AREAS COVERED

This manuscript summarizes the detection of MRD in patients with ALL who undergo allo-HSCT, focusing the effects of positive pre-HSCT MRD and post-HSCT MRD on outcomes as well as MRD-directed interventions.

EXPERT OPINION

Except for MFC and RQ-PCR, other strategies, such as next-generation sequencing and RNAseq, have been developed for MRD determination. Negative effects of positive MRD peri-transplantation on outcomes of ALL patients were observed both in human leukocyte antigen (HLA)-matched sibling donor transplantation and in alternative donor transplantation. Advances have been made in determining the need for transplant according to MRD evaluation after induction or consolidation therapy. A number of approaches, including CAR-T-cell therapy, antibodies (blinatumomab, etc), targeted therapy (imatinib, etc), transplant donor selection, as well as donor lymphocyte infusion and interferon-α, have been successfully used or are promising for peri-transplantation MRD interventions. This progress could lead to the significant improvement of transplant outcomes for ALL patients.