Myelodysplastic syndrome during therapy with immune checkpoint inhibitors: A clinical case

Immune checkpoint inhibitors (ICIs) are widely used in the treatment of patients with solid tumors and lymphoproliferative diseases. However, these agents may cause immune-mediated adverse events, including the myelodysplastic syndrome (MDS) as a rare but serious hematologic side effect. The development of MDS during ICI therapy is usually associated with hyperactivation of the immune system, leading to autoimmune damage to the bone marrow. A clinical case of MDS (refractory anemia without sideroblasts) during ICI therapy is presented. In a 77-year-old patient with stage IV melanoma without a primary site, a persistent decrease in hemoglobin was noted during combination immunotherapy (ipilimumab 1 mg/kg + + nivolumab 3 mg/kg). During the examination, other causes of anemia were excluded – the most common being deficiencies of iron, vitamin B₁₂, and folic acid. A negative Coombs test and normal levels of bilirubin and lactate dehydrogenase ruled out erythrocyte hemolysis. A decrease in the reticulocyte count and the appearance of a significant fraction of immature forms suggested bone marrow dysfunction. Prednisolone and erythropoietin therapy led to only a slight increase in hemoglobin levels, precluding continuation of ICI immunotherapy. Due to the lack of response to supportive therapy, the diagnostic evaluation was continued, and an iliac bone marrow biopsy was performed. The morphological study showed refractory anemia without sideroblasts, an MDS variant. Therefore, the anemia was due to a clonal erythropoietic disorder. This case highlights the need for a comprehensive anemia diagnosis in patients receiving ICIs. In the lack of a response to immunosuppression, after excluding other possible causes of anemia in cancer patients, clonal hematopoietic disorders, including MDS, should be considered. The concomitant MDS requires a multidisciplinary approach to balance the efficacy of cancer therapy with hematologic risks.