Treatment of high-risk myelodysplastic syndromes

Abstract

Myelodysplastic syndrome (MDS) is considered to be a heterogeneous myeloid malignancy with a common origin in the hematopoietic stem cell compartment and is generally divided into lower- and higher-risk forms. While the treatment goals for lower-risk MDS are to decrease transfusion requirements and transformation into acute leukemia, the major aims for higher-risk MDS are to prolong survival and ultimately cure the patient. Although novel agents such as luspatercept and imetelstat have recently been approved as new treatment options for lower-risk MDS, hypomethylating agents currently remain the only approved non-transplant option for higher-risk MDS and are the standard of care for patients not eligible for allogeneic hematopoietic stem cell transplantation (HSCT). Combinations with other drugs as first-line treatment have to date not proven more efficacious than monotherapy in higher-risk MDS, and outcome after the failure of treatment with hypomethylating agents is poor. The only potential cure and standard of care for eligible patients is HSCT and even though the number of transplanted - especially older - MDS patients has increased over time due to better management and greater donor availability, the majority of MDS patients will not be eligible for this curative approach. Current challenges include decreasing the relapse risk, the main cause of HSCT failure. This review summarizes current knowledge on the options of transplant and non-transplant treatment approaches for these patients and demonstrate the unmet clinical need for more effective therapies.

Figure 1.

Proposal of how to assess transplant-eligibility and counsel patients with high-risk myelodysplastic syndrome. MDS: myelodysplastic syndrome; EBMT: European Blood and Marrow Transplantation group; CIBMTR: Center for International Blood and Marrow Transplant Research; NRM: non-relapse mortality; GvHD: graft-versus-host disease.

Figure 2.

Treatment of high-risk myelodysplastic syndrome. IPSS-M: Molecular International Prognostic Scoring System; IPPS-R: Revised International Prognostic Scoring System; BM: bone marrow; MDS: myelodysplastic syndrome; HMA: hypomethylating agent; SCT: stem cell transplantation; MAC: myeloablative conditioning; RIC: reduced intensity conditioning; DLI: donor lymphocyte infusion.