Outcome of Second Allogeneic Hematopoietic Cell Transplantation in Patients With Acute Lymphoblastic Leukemia

The outcome of relapsed childhood acute lymphoblastic leukemia after allogeneic hematopoietic stem-cell transplantations: A single-center experience

In children with high-risk childhood acute leukemia who undergo allogeneic hematopoietic stem-cell transplantation (allo-HSCT), relapse is still the leading cause of treatment failure. The prognosis is poor, yet prospective studies have only limited data on risk factors and outcomes. We aimed to understand the outcomes and prognostic factors for patients with acute lymphoblastic leukemia (ALL) who relapsed following allo-HSCT. We analyzed retrospectively 46 children with childhood acute lymphoblastic leukemia who had relapsed after receiving their first alloHSCT. All these patients received salvage chemotherapy which consisted of fludarabine, cytarabine, and idarubicin before performing a second alloHSCT. The median follow-up of the 46 patients after the first transplantation was 366 days. The median time from first allo-HSCT to relapse was 278.4 ± 238.4 days. Forty-six patients received salvage chemotherapy before the second alloHSCT, and CR was achieved in 32 of 46 patients. However, only 17 (37%) of 46 patients received a second allo-HSCT, and 15 of 46 patients died from disease progression, infections, and bleeding. Twelve patients are still alive after the second allo-HSCT. Two-year overall survival (OS) was 38.9%. Local therapy was given to 10 (21.8%) patients, either as part of systemic therapy or alone. In multivariate analyses, the time of relapse and curative salvage therapy with a second allo-HSCT were identified as significant prognostic factors for OS. Children with leukemia who had relapsed after the first allo-HSCT received salvage chemotherapy. Our statistical analysis showed that the second HSCT could be beneficial for outcomes if patients relapsed beyond 180 days of the first allo-HSCT.

Donor-derived CD19 CAR-T Cells versus Chemotherapy Plus Donor Lymphocyte Infusion for Treatment of Recurrent CD19-positive B-ALL After Allogeneic Hematopoietic Stem Cell Transplantation

OBJECTIVE

This study aimed to compare the efficacy of anti-CD19 chimeric antigen receptor T cells (CAR-T cells) versus chemotherapy plus donor lymphocyte infusion (chemo-DLI) for treating relapsed CD19-positive B-cell acute lymphoblastic leukemia (B-ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

Clinical data of 43 patients with B-ALL who relapsed after allo-HSCT were retrospectively analyzed. Twenty-two patients were treated with CAR-T cells (CAR-T group), and 21 with chemotherapy plus DLI (chemo-DLI group). The complete remission (CR) and minimal residual disease (MRD)-negative CR rates, leukemia-free survival (LFS) rate, overall survival (OS) rate, and incidence of acute graft-versus-host disease (aGVHD), cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were compared between the two groups.

RESULTS

The CR and MRD-negative CR rates in the CAR-T group (77.3% and 61.5%) were significantly higher than those in the chemo-DLI group (38.1% and 23.8%) (P=0.008 and P=0.003). The 1- and 2-year LFS rates in the CAR-T group were superior to those in the chemo-DLI group: 54.5% and 50.0% vs. 9.5% and 4.8% (P=0.0001 and P=0.00004). The 1- and 2-year OS rates in the CAR-T versus chemo-DLI group were 59.1% and 54.5% vs. 19% and 9.5% (P=0.011 and P=0.003). Six patients (28.6%) with grade 2-4 aGVHD were identified in the chemo-DLI group. Two patients (9.1%) in the CAR-T group developed grade 1-2 aGVHD. Nineteen patients (86.4%) developed CRS in the CAR-T group, comprising grade 1-2 CRS in 13 patients (59.1%) and grade 3 CRS in 6 patients (27.3%). Two patients (9.1%) developed grade 1-2 ICANS.

CONCLUSION

Donor-derived anti-CD19 CAR-T-cell therapy may be better, safer, and more effective than chemo-DLI for B-ALL patients who relapse after allo-HSCT.

Prognosis of patients with acute lymphoblastic leukaemia relapsing after allogeneic stem cell transplantation

The outcomes of patients with acute lymphoblastic leukaemia (ALL) presenting relapse after allogeneic stem cell transplant (allo-SCT) are poor, with few data available in this setting.

OBJECTIVE AND METHODS

To evaluate the outcomes of patients with ALL presenting relapsed after allo-SCT, we performed a retrospective study including 132 from 11 centres in Spain.

RESULTS

Therapeutic strategies consisted of palliative treatment (n = 22), chemotherapy (n = 82), tyrosine kinase inhibitors (n = 26), immunotherapy with inotuzumab and/or blinatumumab (n = 19), donor lymphocyte infusions (n = 29 pts), second allo-SCT (n = 37) and CAR T therapy (n = 14). The probability of overall survival (OS) at 1 and 5 years after relapse was 44% (95% confidence interval [CI]: 36%; 52%) and 19% (95% CI: 11%; 27%). In the 37 patients undergoing a second allo-SCT, the 5-year estimated OS probability was 40% [22%; 58%]. Younger age, recent allo-SCT, late relapse, 1st complete remission at 1st allo-SCT and chronic graft-versus-host disease confirmed their positive impact on survival in the multivariable analysis.

CONCLUSION

Despite the poor prognosis of patients with ALL presenting relapse after a first allo-SCT, some can be satisfactorily rescued and a second allo-SCT still remains a valid option for selected patients. Moreover, emerging therapies really might improve ALL patients outcome when relapsing after an allo-SCT.

RCMNet: A deep learning model assists CAR-T therapy for leukemia

Acute leukemia is a type of blood cancer with a high mortality rate. Current therapeutic methods include bone marrow transplantation, supportive therapy, and chemotherapy. Although a satisfactory remission of the disease can be achieved, the risk of recurrence is still high. Therefore, novel treatments are demanding. Chimeric antigen receptor-T (CAR-T) therapy has emerged as a promising approach to treating and curing acute leukemia. To harness the therapeutic potential of CAR-T cell therapy for blood diseases, reliable cell morphological identification is crucial. Nevertheless, the identification of CAR-T cells is a big challenge posed by their phenotypic similarity with other blood cells. To address this substantial clinical challenge, herein we first construct a CAR-T dataset with 500 original microscopy images after staining. Following that, we create a novel integrated model called RCMNet (ResNet18 with Convolutional Block Attention Module and Multi-Head Self-Attention) that combines the convolutional neural network (CNN) and Transformer. The model shows 99.63% top-1 accuracy on the public dataset. Compared with previous reports, our model obtains satisfactory results for image classification. Although testing on the CAR-T cell dataset, a decent performance is observed, which is attributed to the limited size of the dataset. Transfer learning is adapted for RCMNet and a maximum of 83.36% accuracy is achieved, which is higher than that of other state-of-the-art models. This study evaluates the effectiveness of RCMNet on a big public dataset and translates it to a clinical dataset for diagnostic applications.

Outcomes in patients with acute lymphoblastic leukemia who underwent second allogeneic hematopoietic cell transplantation for relapse after first transplantation

Outcomes in patients with acute lymphoblastic leukemia (ALL) who experience relapse after allogeneic hematopoietic cell transplantation (HCT) are unsatisfactory. This study aimed to evaluate the outcomes of patients with ALL who underwent second HCT (HCT2) for relapse after first HCT. It was a single-center retrospective study including adult patients with ALL who underwent HCT2 between 1991 and 2020. The cohort was stratified according to the transplant year, and included 39 patients with a median age of 29 years. A more recent transplant year was associated with achievement of complete remission (CR) and use of reduced-intensity conditioning (RIC), compared with an earlier transplant year. The overall survival (OS) rate and 2-year cumulative incidence of non-relapse mortality (recent vs. earlier) were 55% vs. 8% (P < 0.001) and 26% vs. 75% (P < 0.001), respectively. In multivariate analysis, non-CR (vs. CR; HR 3.6, 95% CI 1.2-11.3, P = 0.025) and myeloablative conditioning (vs. RIC; HR 3.5, 95% CI 1.3-9.4, P = 0.011) were negative prognostic factors for OS. Outcomes of the recent cohort from real-world data are promising, and achieving CR and using the RIC regimen at HCT2 may be an important therapeutic strategy.

Second allogeneic hematopoietic stem cell transplantation in patients with acute leukemia relapsed after allogeneic hematopoietic stem cell transplantation

The prognosis of patients with acute leukemia relapsed after allogeneic hematopoietic stem cell transplantation (HSCT) is dismal. We aimed to evaluate the outcomes and prognostic factors of the second HSCT (HSCT2) in acute leukemia patients relapsed after the first HSCT (HSCT1). We analyzed 80 patients who received HSCT2 for relapsed acute leukemia in two Korean institutes. All but four patients received HSCT2 from a donor other than matched sibling donor: an unrelated donor (URD) in 30 and a familial haploidentical donor (FHD) in 46. Forty-four patients (55.0%) were in complete remission (CR) or CR with incomplete count recovery (CRi) at HSCT2, and the median time from HSCT1 to relapse was 9 months. The 2-year overall survival (OS) and event-free survival (EFS) were 21.0% and 17.5%, respectively. The outcomes were similar between URD and FHD. Multivariate analysis demonstrated that disease status (active disease vs. CR/CRi) at HSCT2 and remission duration after HSCT1 were independent prognostic factors for OS and EFS after HSCT2. HSCT2 from URD or FHD was feasible in patients with acute leukemia relapsed after allogeneic HSCT. Also, our study confirmed two critical prognostic factors; disease status at HSCT2 and remission duration after HSCT1.

Outcome predictors after retransplantation in relapsed acute lymphoblastic leukemia: a multicenter, retrospective study

Retransplantation is the only curative treatment option for patients with acute lymphoblastic leukemia (ALL) that has relapsed after allogeneic hematopoietic cell transplantation (allo-HCT); however, data in this setting remain scant. Hence, this multicenter, retrospective study aims to determine outcome predictors after retransplantation in relapsed ALL. We examined 55 recipients who underwent multiple allo-HCTs during 2006-2018. The 2-year overall survival (OS), progression-free survival (PFS), and non-relapse mortality rates were 35.9%, 29.1%, and 23.6%, respectively. We observed a trend of better outcome in Ph + ALL (n = 22) patients compared with non-Ph ALL (n = 33) patients; the 2-year PFS was 40.9% versus 21.2%, indicating a beneficial effect of more potent second- or third-generation tyrosine kinase inhibitors. Univariate analysis revealed that late relapse after the previous transplant was the only significant predictor of better transplant outcome among Ph + ALL patients, whereas factors related to prolonged OS/PFS in non-Ph ALL patients were late relapse after the previous transplant, longer duration from disease relapse/progression to second or more allo-HCT, disease status at the transplantation, and good performance status. Nevertheless, further investigations are warranted to determine whether novel molecular-targeted agents with higher efficacy and fewer toxicities could exceed conventional chemotherapies as a bridging strategy to next allo-HCT and improve the outcomes of non-Ph ALL patients.

Donor-derived CD19 CAR-T cell therapy of relapse of CD19-positive B-ALL post allotransplant

Safety and efficacy of allogeneic anti-CD19 chimeric antigen receptor T cells (CAR-T cells) in persons with CD19-positive B-cell acute lymphoblastic leukemia (B-ALL) relapsing after an allotransplant remain unclear. Forty-three subjects with B-ALL relapsing post allotransplant received CAR-T cells were analyzed. 34 (79%; 95% confidence interval [CI]: 66, 92%) achieved complete histological remission (CR). Cytokine release syndrome (CRS) occurred in 38 (88%; 78, 98%) and was ≥grade-3 in 7. Two subjects died from multiorgan failure and CRS. Nine subjects (21%; 8, 34%) developed ≤grade-2 immune effector cell-associated neurotoxicity syndrome (ICANS). Two subjects developed ≤grade-2 acute graft-versus-host disease (GvHD). 1-year event-free survival (EFS) and survival was 43% (25, 62%). In 32 subjects with a complete histological remission without a second transplant, 1-year cumulative incidence of relapse was 41% (25, 62%) and 1-year EFS and survival, 59% (37, 81%). Therapy of B-ALL subjects relapsing post transplant with donor-derived CAR-T cells is safe and effective but associated with a high rate of CRS. Outcomes seem comparable to those achieved with alternative therapies but data from a randomized trial are lacking.

Hematopoietic Cell Transplantation in the Treatment of Adult Acute Lymphoblastic Leukemia: Updated 2019 Evidence-Based Review from the American Society for Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in adults with acute lymphoblastic leukemia (ALL) is reviewed and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the recommendations. A panel of ALL experts developed consensus on the treatment recommendations based on the evidence. Allogeneic HCT offers a survival benefit in selected patients with ALL, and this review summarizes the standard indications as well as the areas of controversy. There is now greater experience with pediatric-inspired chemotherapy regimens that has transformed upfront therapy for adult ALL, resulting in higher remission rates and overall survival. This in turn has increased the equipoise around decision making for ALL in first complete remission (CR1) when there is no measurable residual disease (MRD) at the end of induction and/or consolidation. Randomized studies are needed for adults with ALL to compare allogeneic HCT in CR1 with pediatric-inspired chemotherapy alone. Indications for transplantation in the evolving landscape of MRD assessments and novel targeted and immune therapeutics remain important areas of investigation.