Donor lymphocyte infusion for leukemia relapse after hematopoietic stem cell transplantation

Ruxolitinib on acute graft-versus-host disease prophylaxis after modified donor lymphocyte infusion

OBJECTIVE

To evaluate the effectiveness of ruxolitinib on acute graft-versus-host disease (aGVHD) prophylaxis and its impact on graft-versus-leukemia (GVL) effect in patients after modified donor lymphocyte infusion (mDLI).

METHODS

We retrospectively included patients with relapsed leukemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT) who received ruxolitinib prophylaxis between October 2018 and April 2020. The incidence of aGVHD, disease-free survival (DFS), overall survival (OS), and treatment safety were evaluated.

RESULTS

Seventeen patients were followed up for a median time of 8 months (range: 1-26 months). The incidence of aGVHD on Day 30 after mDLI was 41.2% and ranged from Grade 1 to 4; ten of 17 patients (58.8%) achieved a complete response (CR), and two (11.8%) had a partial response (PR). Cytomegalovirus (CMV) reactivation rate was 23.5%, and the median time from mDLI to CMV reactivation was 48.5 days. The mean DFS and OS after mDLI were 1.0 (95% CI 0.0-3.5) and 9.0 (95% CI 1.2-16.8) months, respectively. The causes of death for 10 patients were leukemia relapse (n = 5), aGVHD and septic shock (n = 3), intracranial lesion (n = 1), and COVID-19 (n = 1).

CONCLUSIONS

We reported encouraging results of ruxolitinib monotherapy in the prevention of aGVHD and maintenance of GVL for post-transplantation relapsed patients, even though being at high risk with poor initial prognosis.

How to Combine the Two Landmark Treatment Methods-Allogeneic Hematopoietic Stem Cell Transplantation and Chimeric Antigen Receptor T Cell Therapy Together to Cure High-Risk B Cell Acute Lymphoblastic Leukemia?

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has made tremendous progress in the last few decades and is increasingly being used worldwide. The success of haploidentical HSCT has made it possible to have "a donor for everyone". Patients who received transplantation in remission may have a favorable outcome, while those who were transplanted in advanced stages of disease have a poor prognosis. Although chimeric antigen receptor T (CAR-T) cell therapy is currently a milestone in the immunotherapy of relapsed or refractory (R/R) B cell acute lymphoblastic leukemia (B-ALL) and has demonstrated high remission rates in patients previously treated in multiple lines, the relatively high relapse rate remains a barrier to CAR-T cell therapy becoming an excellent cure option. Therefore, combining these two approaches (allo-HSCT and CAR-T cell therapy) is an attractive area of research to further improve the prognosis of R/R B-ALL. In this review, we will discuss the current clinical practices of combining allo-HSCT with CAR-T cell therapy based on available data, including CAR-T cells as a bridge to allo-HSCT for R/R B-ALL and CAR-T cell infusion for post-transplant relapse. We will further explore not only other possible ways to combine the two approaches, including CAR-T cell therapy to clear minimal residual disease peri-transplantation and incorporation of CAR technology to treat graft-versus-host disease, but also the potential of CAR-T cells as a part of allo-HSCT.

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.

Cellular Immunotherapy for Hematologic Malignancies: Beyond Bone Marrow Transplantation

Immunotherapy has changed treatment practices for many hematologic malignancies. Even in the current era of targeted therapy, chemotherapy remains the backbone of treatment for many hematologic malignancies, especially in acute leukemias, where relapse remains the major cause of mortality. Application of novel immunotherapies in hematology attempts to harness the killing power of the immune system against leukemia and lymphoma. Cellular immunotherapy is evolving rapidly for high-risk hematologic disorders. Recent advances include chimeric antigen-receptor T cells, mesenchymal stromal/stem cells, dendritic cell tumor vaccines, cytokine-induced killer cells, and virus-specific T cells. The advantages of nontransplantation cellular immunotherapy include suitability for patients for whom transplantation has failed or is contraindicated, and a potentially less-toxic treatment alternative to transplantation for relapsed/refractory patients. This review examines those emerging cellular immunotherapies that are changing treatment paradigms for patients with hematologic malignancies.

Graft-versus-Leukemia Effect Following Hematopoietic Stem Cell Transplantation for Leukemia

The success of hematopoietic stem cell transplantation (HSCT) lies with the ability of the engrafting immune system to remove residual leukemia cells via a graft-versus-leukemia effect (GvL), caused either spontaneously post-HSCT or via donor lymphocyte infusion. GvL effects can also be initiated by allogenic mismatched natural killer cells, antigen-specific T cells, and activated dendritic cells of leukemic origin. The history and further application of this GvL effect and the main mechanisms will be discussed and reviewed in this chapter.

Adoptive Immunotherapies After Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Hematologic Malignancies

Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for patients with chemotherapy-resistant hematologic malignancies that are usually fatal in absence of treatment. Hematopoietic stem cell transplantation is associated with significant early and late morbidity and mortality. Graft-versus-host disease, infections, and relapse are the most important causes of mortality after HSCT. Until now, these complications have been managed mainly with pharmacological drugs, but in some situations, this approach clearly shows its limit. As such, there is a significant need for novel therapies for the treatment of complications after allogeneic HSCT. In this review, the currently available adoptive immunotherapies offering an alternative in case of treatment failure of HSCT complications will be described. The results of the main clinical trials based on immune cell infusion will be discussed and the strategies aiming at maximizing cytotoxic T-lymphocyte, regulatory T-cell, natural killer cell, cytokine-induced killer cell, and γδ T-cell efficacies in the context of immunotherapy approaches after allogeneic HSCT in patients with hematologic malignancies will be gathered.

Immunotherapy in acute myeloid leukemia

Treatment of acute myeloid leukemia (AML) with current chemotherapy regimens is still disappointing, with overall survival rates of ≤40% at 5 years. It is now well established that AML cells can evade the immune system through multiple mechanisms, including the expression of the enzyme indoleamine 2,3 dioxygenase. Immunotherapeutic strategies, including both active, such as vaccination with leukemia-associated antigens, and passive, such as adoptive transfer of allogeneic natural killer cells, may overcome leukemia escape and lead to improved cure. Allogeneic hemopoeitic stem cell transplantation, the most effective treatment of AML, is the best known model of immunotherapy. Following transplant, recipient AML cells are eradicated by donor immune cells through the graft-versus-leukemia (GVL) effect. However, GVL is clinically associated with graft-versus-host disease, the major cause of mortality after transplant. GVL is mediated by donor T cells recognizing either leukemia-associated antigens or minor as well as major histocompatibility antigens. Several innovative strategies have been devised to generate leukemia reactive T cells so as to increase GVL responses with no or little graft-versus-host disease.

Efficacy of adoptive immunotherapy with donor lymphocyte infusion in relapsed lymphoid malignancies

Aims: There is a perceived benefit associated with the administration of donor lymphocyte infusion (DLI) in patients with lymphoid malignancies relapsing after allogeneic hematopoietic cell transplantation. However, it is unclear if and how this benefit varies according to specific diseases. Because administration of DLI is not universally effective and could be associated with significant toxicities resulting in morbidity and mortality, it is imperative to identify cases where benefits outweigh harms of the procedure. Materials & methods: We conducted a systematic review of the published literature and extracted and pooled data independently for each disease cohort: acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), multiple myeloma (MM), non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). Results: In summary, 39 studies met inclusion criteria. The pooled proportion (95% CI) for complete response was 27% (16–40) in ALL, 55% (15–92) in CLL, 26% (19–33) in MM, 52% (33–71) in NHL and 37% (20–56) in HL. Conclusion: Complete response rates appear higher when DLI is used for relapsed CLL and lymphomas (NHL and HL), and less pronounced in ALL or MM. Absence of data pertaining to disease-specific prognostic determinants, such as adverse genetic or molecular abnormalities, or quantitative disease burden when applicable, limit our ability to identify cases in whom benefits from DLI outweigh risks associated with the procedure within a particular disease.

Overlooking evolution: a systematic analysis of cancer relapse and therapeutic resistance research

Cancer therapy selects for cancer cells resistant to treatment, a process that is fundamentally evolutionary. To what extent, however, is the evolutionary perspective employed in research on therapeutic resistance and relapse? We analyzed 6,228 papers on therapeutic resistance and/or relapse in cancers and found that the use of evolution terms in abstracts has remained at about 1% since the 1980s. However, detailed coding of 22 recent papers revealed a higher proportion of papers using evolutionary methods or evolutionary theory, although this number is still less than 10%. Despite the fact that relapse and therapeutic resistance is essentially an evolutionary process, it appears that this framework has not permeated research. This represents an unrealized opportunity for advances in research on therapeutic resistance.

Clinical evaluation of cellular immunotherapy in acute myeloid leukaemia

Immunotherapy is currently under active investigation as an adjuvant therapy to improve the overall survival of patients with acute myeloid leukaemia (AML) by eliminating residual leukaemic cells following standard therapy. The graft-versus-leukaemia effect observed following allogeneic haematopoietic stem cell transplantation has already demonstrated the significant role of immune cells in controlling AML, paving the way to further exploitation of this effect in optimized immunotherapy protocols. In this review, we discuss the current state of cellular immunotherapy as adjuvant therapy for AML, with a particular focus on new strategies and recently published results of preclinical and clinical studies. Therapeutic vaccines that are being tested in AML include whole tumour cells as an autologous source of multiple leukaemia-associated antigens (LAA) and autologous dendritic cells loaded with LAA as effective antigen-presenting cells. Furthermore, adoptive transfer of cytotoxic T cells or natural killer cells is under active investigation. Results from phase I and II trials are promising and support further investigation into the potential of cellular immunotherapeutic strategies to prevent or fight relapse in AML patients.