Survival of early posthematopoietic stem cell transplantation relapse of myeloid malignancies

The predictive value of T-cell chimerism for disease relapse after allogeneic hematopoietic stem cell transplantation

Introduction

Chimerism is closely correlated with disease relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, chimerism rate is dynamic changes, and the sensitivity of different chimerism requires further research.

Methods

To investigate the predictive value of distinct chimerism for relapse, we measured bone marrow (BM), peripheral blood (PB), and T-cell (isolated from BM) chimerism in 178 patients after allo-HSCT.

Results

Receiver operating characteristic (ROC) curve showed that T-cell chimerism was more suitable to predict relapse after allo-HSCT compared with PB and BM chimerism. The cutoff value of T-cell chimerism for predicting relapse was 99.45%. Leukemia and myelodysplastic syndrome (MDS) relapse patients' T-cell chimerism was a gradual decline from 2 months to 9 months after allo-HSCT. Higher risk of relapse and death within 1 year after allo-HSCT. The T-cell chimerism rates in remission and relapse patients were 99.43% and 94.28% at 3 months after allo-HSCT (P = 0.009), 99.31% and 95.27% at 6 months after allo-HSCT (P = 0.013), and 99.26% and 91.32% at 9 months after allo-HSCT (P = 0.024), respectively. There was a significant difference (P = 0.036) for T-cell chimerism between early relapse (relapse within 9 months after allo-HSCT) and late relapse (relapse after 9 months after allo-HSCT) at 2 months after allo-HSCT. Every 1% increase in T-cell chimerism, the hazard ratio for disease relapse was 0.967 (95% CI: 0.948-0.987, P<0.001).

Discussion

We recommend constant monitoring T-cell chimerism at 2, 3, 6, and 9 months after allo-HSCT to predict relapse.

Demethylating agents in combination with CD7-targeted CAR-T for the successful treatment of a case with mixed-phenotype acute leukemia relapsed after allogeneic hematopoietic stem cell transplantation: A Case Report

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has cured many patients with malignant hematologic diseases such as mixed phenotype acute leukemia (MPAL), while those relapsing after allo-HSCT still exhibit high mortality, poor prognosis, and no standard treatment modalities. It is necessary to explore more therapeutic modalities for patients with post-transplant relapse to obtain a better prognosis.

Case presentation

In this case report, a young male with MPAL received allo-HSCT after reaching complete remission (CR) by induction chemotherapy. Unfortunately, relapse of both myeloid and T lineages occurred nine months later. After receiving demethylating chemotherapy, myeloid lineage measurable residual disease (MRD) turned negative. T-lineage MRD turned negative after CD7-targeted chimeric antigen receptor (CAR)-T cell therapy. The bone marrow remained MRD-negative for 4 months. This case preliminarily demonstrated a long-lasting CR with CD7-targeted CAR-T cell therapy, allowing a better prognosis.

Conclusion

Demethylating drugs combined with CD7-targeted CAR-T cell therapy is feasible in treating MPAL patients with relapse after transplantation, with good efficacy and safety, which will be a promising treatment option for MPAL.

The prevention of disease relapse after allogeneic hematopoietic cell transplantation in acute myeloid leukemia

Disease relapse represents by far the most frequent cause of hematopoietic cell transplantation (HCT) failure. Patients with acute leukemia suffering relapse after HCT have limited conventional treatment options with little possibility of cure and represent, de facto, suitable candidates for the evaluation of novel cellular and biological-based therapies. Donor lymphocyte infusions (DLI) has been one of the first cellular therapies adopted to treat post HCT relapse of acute leukemia patients and still now, it is widely adopted in preemptive and prophylactic settings, with renewed interest for manipulated cellular products such as NK-DLI. The acquisition of novel biological insights into pathobiology of leukemia relapse are translating into the clinic, with novel combinations of target therapies and novel agents, helping delineate new therapeutical landscapes. Hypomethylating agents alone or in combination with novel drugs demonstrated their efficacy in pre-clinical models and controlled trials. FLT3 inhibitors represent an essential therapeutical instrument incorporated in post-transplant maintenance strategies. The Holy grail of allogeneic transplantation lies in the separation of graft-vs.-host disease from graft vs. tumor effects and after more than five decades, is still the most ambitious goal to reach and many ways to accomplish are on their way.

Using stroma-anchoring cytokines to augment ADCC: a phase 1 trial of F16IL2 and BI 836858 for posttransplant AML relapse

Natural killer (NK) cells are key effectors in cancer immunosurveillance and posttransplant immunity, but deficiency of environmental signals and insufficient tumor recognition may limit their activity. We hypothesized that the antibody-mediated anchoring of interleukin-2 (IL-2) to a spliced isoform of the extracellular matrix (ECM) glycoprotein tenascin-C would potentiate NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) against leukemic blasts. In this novel-novel combination, dose-escalation phase 1 trial, we enrolled patients with posttransplant acute myeloid leukemia (AML) relapse to evaluate the safety, pharmacokinetics, pharmacodynamics, and preliminary activity of the antibody-cytokine fusion F16IL2 (10-20x106 IU IV, days 1, 8, 15, and 22 of 28-day cycles) in combination with the anti-CD33 antibody BI 836858 (10-40 mg IV, 2 days after each F16IL2 infusion). Among 15 patients (median [range] age, 50 [20-68] years) treated across 4 dose levels (DL), 6 (40%) had received 2 or 3 prior transplantations. The most frequent adverse events were pyrexia, chills and infusion-related reactions, which were manageable, transient and of grade ≤ 2. One dose-limiting toxicity occurred at each of DL 3 (pulmonary edema) and 4 (GVHD). Three objective responses were observed among 7 patients treated at the 2 higher DL, whereas no responses occurred at the 2 starting DL. Combination therapy stimulated the expansion and activation of NK cells, including those expressing the FcγRIIIA/CD16 receptor. ECM-targeted IL-2 combined with anti-CD33 immunotherapy represents an innovative approach associated with acceptable safety and encouraging biologic and clinical activity in posttransplant AML relapse. This trial was registered at EudraCT (2015-004763-37).

Survival following relapse after allogeneic hematopoietic cell transplantation for acute leukemia and myelodysplastic syndromes in the contemporary era

OBJECTIVE/BACKGROUND

Relapse is the most common cause of treatment failure after allogeneic hematopoietic cell transplantation (alloHCT). No standard of care exists, and a wide range of treatments are used for post-alloHCT relapse. In the recent era, several novel therapies including targeted agents are available for acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), and myelodysplastic syndrome (MDS).

METHODS

We reviewed outcomes after alloHCT relapse, with or without use of these newer agents for ALL, AML, and MDS. In total, 115 adults with relapsed or refractory ALL (n = 17), AML (n = 67), and MDS (n = 31) at median 5 (range, 1-64) months after their first alloHCT in 2010-2018 were included.

RESULTS

Median follow-up was 19 (range, 6-80) months after relapse from alloHCT. Targeted agents were given to 29 (25%) patients. In multivariable analysis, use of targeted agent at any time point after relapse was not associated with survival. Matched unrelated (vs. matched sibling; hazard ratio [HR] 1.70; p = .027) or haploidentical donor grafts (vs. matched sibling; HR 2.69; p = .003), presence of grade II-IV acute graft-versus-host disease before relapse (HR 2.46; p < .001), and less than 12 months from HCT to relapse (<6 vs. > 12 months; HR 6.34; p < .001; 6-12 vs. > 12 months; HR 3.16; p = .005) were adverse prognostic factors for post-relapse survival.

CONCLUSION

Outcomes after alloHCT relapse remain poor regardless of the novel agent use. Innovative treatment strategies are needed to improve outcomes after relapse post-alloHCT.

T cell optimization for graft-versus-leukemia responses

Protection from relapse after allogeneic hematopoietic cell transplantation (HCT) is partly due to donor T cell-mediated graft-versus-leukemia (GVL) immune responses. Relapse remains common in HCT recipients, but strategies to augment GVL could significantly improve outcomes after HCT. Donor T cells with αβ T cell receptors (TCRs) mediate GVL through recognition of minor histocompatibility antigens and alloantigens in HLA-matched and -mismatched HCT, respectively. αβ T cells specific for other leukemia-associated antigens, including nonpolymorphic antigens and neoantigens, may also deliver an antileukemic effect. γδ T cells may contribute to GVL, although their biology and specificity are less well understood. Vaccination or adoptive transfer of donor-derived T cells with natural or transgenic receptors are strategies with potential to selectively enhance αβ and γδ T cell GVL effects.

Immune Escape after Hematopoietic Stem Cell Transplantation (HSCT): From Mechanisms to Novel Therapies

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. Recent advances in understanding its molecular basis have opened the way to new therapeutic strategies, including targeted therapies. However, despite an improvement in prognosis it has been documented in recent years (especially in younger patients) that allogenic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment in AML and the first therapeutic option for high-risk patients. After allo-HSCT, relapse is still a major complication, and is observed in about 50% of patients. Current evidence suggests that relapse is not due to clonal evolution, but instead to the ability of the AML cell population to escape immune control by a variety of mechanisms including the altered expression of HLA-molecules, production of anti-inflammatory cytokines, relevant metabolic changes and expression of immune checkpoint (ICP) inhibitors capable of “switching-off” the immune response against leukemic cells. Here, we review the main mechanisms of immune escape and identify potential strategies to overcome these mechanisms.

Survival of early posthematopoietic stem cell transplantation relapse of myeloid malignancies

Objective

Relapse of AML after allogeneic hematopoietic stem cell transplantation (HSCT) has a poor prognosis, and standard of care therapy is lacking. Early (<6 months) relapse is associated with dismal outcome, while the majority of relapses occur early after transplantation. A more precise indication which patients could benefit from reinduction therapy is warranted.

Methods

We retrospectively analyzed outcomes of 83 patients with postallogeneic HSCT relapse. Patients were divided based on intention to treat (curative vs supportive care).

Results

Of the 50 patients treated with curative intent, 44% reached complete remission (CR) upon reinduction chemotherapy, and of these patients, 50% survived. Two survivors reached CR after immunotherapy (donor lymphocyte infusion (DLI), without reinduction chemotherapy). Sixty‐nine percent of the survivors had received high‐intensity cytarabine treatment, followed by immunologic consolidation. Relapse <3 months after transplantation was predictive for adverse survival (P = .004), but relapse <6 months was not. In fact, >50% of the survivors had a relapse <6 months.

Conclusion

We confirmed the dismal prognosis of postallogeneic HSCT relapse. Importantly, our data demonstrate that patients fit enough to receive high‐dose chemotherapy, even when relapse occurred <6 months, had the best chance to obtain durable remissions, in particular when immunologic consolidation was performed after reaching CR.