The primary objective of this study is to describe the response to treatment with biosimilar EPO alpha in MDS patients who had already been treated with "originator" EPO alpha and were responsive, and in patients who started treatment with biosimilar EPO alpha

To date, therapy with erythropoiesis-stimulating agents (ESAs) has been shown to be effective in the treatment of symptomatic anemia in patients with Myelodysplastic Syndrome ( MDS) at low to intermediate risk, with the percentage of responsive patients ranging from 15 to 63%, depending on the characteristics of the patients treated, and averaging 45%.

Significant improvement in survival and quality of life was observed in treatment-responsive patients compared with non-responsive patients.

Recently, biosimilar ESAs have been introduced into clinical practice, and in patients with renal failure anemia and anemia associated with antineoplastic chemotherapy, their efficacy and safety have been demonstrated.

However, data on the efficacy and safety of biosimilar ESAs in patients with MDS are scarce to date, and efficacy and safety data for the purpose of their approval have been mainly extrapolated from studies conducted in patients with anemia from renal failure and anemia from antineoplastic chemotherapy. In these conditions bone marrow erythropoiesis is reduced but not qualitatively impaired as in MDS.

These considerations may justify a retrospective study examining the efficacy and safety of biosimilar EPO alpha in a real-life setting in anemic MDS patients.

Inclusion Criteria:

MDS patients with symptomatic anemia (pre-treatment hemoglobin < 10g/dL) who started treatment with biosimilar EPO alpha, diagnosed according to the WHO 2016 classification, and characterized by very low, low, or intermediate IPSS-R risk and a pre-treatment serum EPO level < 500 U/L, who started treatment with biosimilar EPO alpha at the U. O. of Hematology of IRCCS AOUBO during the period from 01/06/2018 to 31/12/2021.

• Age ≥ 18 years at the time of enrollment
• Acquisition of informed consent to study participation and data processing

Exclusion Criteria:

• - Presence of other possible contributory causes of anemia (e.g., anemia from chronic inflammatory disease, hemolysis, hemorrhage)
• Poor compliance with treatment
• Very impaired general clinical condition (ECOG performance status > 3)
• Concomitant treatment with antineoplastic cytotoxic drugs

All patients with MDS who started treatment with biosimilar EPO alpha at the "Seràgnoli" Institute, U.O. of Hematology of IRCCS AOU of Bologna during the period from 01 Jun 2018 to 31 Dec 2021 will be enrolled in the study.

Specifically, the population will consist of

• patients who initiated treatment after having already been treated with "originator" EPO alfa and responsive to treatment at the time of initiation of biosimilar EPO alfa, and
• patients who started treatment without previous treatment with biosimilar EPO alfa