Allogeneic Hematopoietic Cell Transplantation for Myelodysplastic Syndrome: Current Status

Impact of copy neutral loss of heterozygosity and total genome aberrations on survival in myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases with varying genetic aberrations. Half of MDS patients have normal karyotype, obscuring the underlying condition indicating a need for new markers for improved diagnostics and prognosis. We performed a retrospective review of sequential MDS patients who underwent chromosomal genetic array testing (CGAT) between November 2008 and March 2014. Total Genomic Aberration (TGA) scores, with and without copy-neutral loss of heterozygosity (cnLOH), were compared to pathology and clinical data. Of 68 MDS participants, 50 patients (73%) had abnormal CGAT results. 32% showedcnLOH, 41% had no cnLOH but displayed copy number aberration (CNAs). Of 26 patients with normal cytogenetics, 46% had clonal abnormalities by CGAT. Abnormal CGAT results were associated with lower overall survival (P=0.04). Overall survival in patients with TGA above the median (68.6 Mb) was significantly inferior to those below the median (HR=2.9, 95% CI=1.3-6.8, P=0.01). Furthermore, there was an observed association between increased TGA and increased dysplastic lineages (Ptrend=0.003). CGAT studies provide important findings that extend beyond current standard testing. Clinical utility of CGAT includes improved diagnostic yield, correlation of extent of TGA and increased dysplastic features, and survival.

Should elderly patients with higher-risk myelodysplastic syndromes undergo allogeneic hematopoietic stem cell transplantation?

Myelodysplastic syndromes (MDS) include a group of hematopoietic malignancies characterized by dysplastic changes, ineffective hematopoiesis and variable risk of leukemic progression. At diagnosis, 86% of MDS patients are ≥60 years. Azacitidine, the only drug that prolongs life in high-risk (HR)-MDS patients, adds a median of only 9.5 months to life. Allogeneic stem cell transplantation (alloSCT) remains the only potentially curative approach. Despite recent improvements including use of reduced intensity conditioning (RIC) that decrease transplant-related mortality, alloSCT continues to be used rarely in elderly MDS. There is paucity of data regarding outcomes of RIC alloSCT in elderly MDS patients, especially in direct comparison with azanucleosides. In this paper, the authors discuss the recent Markov decision analysis by Koreth et al. in which investigators demonstrated superior survival of patients with HR-MDS aged 60-70 years who underwent RIC alloSCT in comparison with those who were treated with azanucleosides.

Current therapy of myelodysplastic syndromes

After being a neglected and poorly-understood disorder for many years, there has been a recent explosion of data regarding the complex pathogenesis of myelodysplastic syndromes (MDS). On the therapeutic front, the approval of azacitidine, decitabine, and lenalidomide in the last decade was a major breakthrough. Nonetheless, the responses to these agents are limited and most patients progress within 2 years. Allogeneic stem cell transplantation remains the only potentially curative therapy, but it is associated with significant toxicity and limited efficacy. Lack or loss of response after standard therapies is associated with dismal outcomes. Many unanswered questions remain regarding the optimal use of current therapies including patient selection, response prediction, therapy sequencing and combinations, and management of resistance. It is hoped that the improved understanding of the underpinnings of the complex mechanisms of pathogenesis will be translated into novel therapeutic approaches and better prognostic/predictive tools that would facilitate accurate risk-adaptive therapy.