Lack of activity of allogeneic stem cell transplantation with reduced-intensity conditioning regimens in advanced sarcomas

Graft-versus-cancereffect and innovative approaches in thetreatment of refractory solid tumors

Background/aim

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been used for the treatment of various refractory solid tumors during the last two decades. After the demonstration of graft-versus-leukemia (GvL) effect in a leukemic murine model following allo-HSCT from other strains of mice, graft-versus-tumor (GvT) effect in a solid tumor after allo-HSCT has also been reported in a murine model in 1984. Several trials have reported the presence of a GvT effect in patients with various refractory solid tumors, including renal, ovarian and colon cancers, as well as soft tissue sarcomas [1]. The growing data on haploidentical transplants also indicate GvT effect in some pediatric refractory solid tumors. Novel immunotherapy-based treatment modalities aim at inducing an allo-reactivity against the metastatic solid tumor via a GvT effect. Recipient derived immune effector cells (RDICs) in the antitumor reactivity following allo-HSCT have also been considered as an emerging therapy for advanced refractory solid tumors.

Conclusion

This review summarizes the background, rationale, and clinical results of immune-based strategies using GvT effect for the treatment of various metastatic and refractory solid tumors, as well as innovative approaches such as haploidentical HSCT, CAR-T cell therapies and tumor infiltrating lymphocytes (TIL).

Review of allogeneic hematopoietic stem cell transplantation with reduced intensity conditioning in solid tumors excluding breast cancer

Solid tumors in adults constitute a heterogeneous group of malignancy originating from various organ systems. Solid tumors are not completely curable by chemotherapy, even though some subgroups are very chemo-sensitive. Recently, oncologists have focused on the use of allogeneic hematopoietic stem cell transplantation (allo-HSCT) with reduced intensity conditioning (RIC) for the treatment of some refractory solid tumors. After the demonstration of allogeneic graft-versus-leukemia effect in patients with hematological malignancies who received allo-HSCT, investigators evaluated this effect in patients with refractory metastatic solid tumors. According to data from experimental animal models and preliminary clinical trials, a graft-versus-tumor (GvT) effect may also be observed in the treatment of some solid tumors (e.g., renal cell cancer, colorectal cancer, etc.) after allo-HSCT with RIC. The use of RIC regimens offers an opportunity of achieving full-donor engraftment with GvT effect, as well as, a reduced transplant-related mortality. Current literature suggests that allo-HSCT with RIC might become a choice for elderly and medically fragile patients with refractory metastatic solid tumors.

Adoptive immunotherapy against sarcomas

INTRODUCTION

Conventional treatments reached an unsatisfactory therapeutic plateau in the treatment of advanced unresectable bone and soft tissue sarcomas that remain an unsolved medical need. Several evidences support the concept that adoptive immunotherapy may effectively integrate within the complex and multidisciplinary treatment of sarcomas.

AREAS COVERED

In this work we reviewed adoptive immunotherapy strategies that have been explored in sarcoma settings, with specific focus on issues related to their clinic transferability. We schematically divided approaches based on T lymphocytes specific for MHC-restricted tumor-associated antigens or relying on MHC-independent immune effectors such as natural killer (NK), cytokine-induced killer (CIK) or γδ T cells.

EXPERT OPINION

Preclinical findings and initial clinical reports showed the potentialities and drawbacks of different adoptive immunotherapy strategies. The expansion of tumor infiltrating lymphocytes is difficult to be reproduced outside melanoma. Genetically redirected T cells appear to be a promising option and initial reports are encouraging against patients with sarcomas. Adoptive immunotherapy with MHC-unrestricted effectors such as NK, CIK or γδ T cells has recently shown great preclinical potential in sarcoma setting and biologic features that may favor clinical transferability. Combination of different immunotherapy approaches and integration with conventional treatments appear to be key issues for successful designing of next clinical trials.

High-dose chemotherapy and stem cell rescue for high-risk Ewing's family of tumors

The prognosis for high-risk Ewing's tumors has been improved by multimodal radiation and chemotherapy. Ewing's family of tumors requires risk-adapted treatment. Risk stratification is dependent on stage, tumor localization and volume, and the pattern of disease spread at the time of diagnosis and the time of relapse. The concepts for high-dose therapy followed by hematopoietic cell transplantation in Ewing's family of tumors are based on dose-response and dose-intensity relationships. This article will discuss the use of high-dose therapy followed by hematopoietic cell transplantation, focusing on recent progress with respect to agent combinations, dose and outcomes of therapy.

Immunotherapeutic Intervention against Sarcomas

Advances in systemic therapy for sarcoma have produced, over the last two decades, relatively short-term benefits for the majority of patient. Among the novel biologic therapeutics that will likely increase our ability to cure human cancer in the years to come, immunotherapy is one of the most promising approaches. While past attempts to use immunotherapy have failed to dramatically shift the paradigm of care for the treatment of patients with sarcoma, major advances in basic and translational research have resulted, in more recent years, in clinical trial activity that is now beginning to generate promising results. However, to move from “proof of principle” to large scale clinical applicability, we need well-designed, multi-institutional clinical trials, along with continuous laboratory research to explore further the immunological characteristics of individual sarcoma subtypes and the consequent tailoring of therapy.

Transplantation of allogeneic hematopoietic stem cells: an emerging treatment modality for solid tumors

Allogeneic transplantation of hematopoietic cells from an HLA-compatible donor has been used to treat hematologic malignancies. Allogeneic transplantation not only replaces the marrow affected by the disease, but exerts an immune graft-versus-tumor (GVT) effect mediated by donor lymphocytes. The development of nonmyeloablative conditioning regimens before allogeneic transplantation has allowed this therapy to be used in elderly and disabled patients. An allogeneic GVT effect is observed in a proportion of patients with renal, breast, colorectal, ovarian, and pancreatic cancer treated with allogeneic transplantation. In general, the tumor response is associated with the development of acute and chronic graft-versus-host disease. Further improvements will depend on the identification of the antigen targets of GVT, and on reduction of the toxicity of the procedure. Targeted therapies may complement the immune effect of allogeneic transplantation. We present updated results from the literature and data recently placed on file at the European Bone Marrow Transplantation Solid Tumors Working Party.