Immunosuppressive therapy is one therapy option for treatment of patients with lower-risk myelodysplastic syndromes. However, the use of several different immunosuppressive regimens, the lack of high-quality studies, and the absence of validated predictive biomarkers pose important challenges. We conducted a systematic review and meta-analysis according to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines and searched MEDLINE via PubMed, Ovid EMBASE, COCHRANE registry of clinical trials (CENTRAL), and the Web of Science without language restriction from inception through September 2018 as well as relevant conference proceedings and abstracts. for prospective cohort studies or clinical trials investigating immunosuppressive therapy in myelodysplastic syndromes. Fixed and Random-effects models were used to pool response rates. We identified nine prospective cohort studies and 14 clinical trials with a total 570 patients. The overall response rate was 43% (95% confidence interval [CI] 34.2%-52.3%) including a complete remission rate of 12.5% (95% CI 9.3%-16.6%) and red blood cell transfusion independence rate of 30.6% (95% CI 23.2%-39.2%). The most commonly used forms of immunosuppressive therapy were anti-thymocyte globulin alone or in combination with cyclosporin A with a trend towards higher response rates with combination therapy. Progression rate to acute myeloid leukemia was 8.6% per patient year (95% CI 3.3%-13.9%). Overall survival and adverse events were only inconsistently reported. We were unable to validate any biomarkers predictive of a therapeutic response to immunosuppressive therapy. Immunosuppressive therapy for treatment of lower-risk myelodysplastic syndrome patients can be successful to alleviate transfusion burden and associated sequelae.
