This is unpublished

Kleber Yotsumoto
M.D., Ph.D.

he, him, his
Physician & Research Faculty
Associate Professor, Division of Hematology and Oncology, University of Washington
Director, Sickle Cell Disease and Iron Overload Program, Fred Hutchinson Cancer Center
Sites of Practice
Fred Hutchinson Cancer Center - South Lake Union

Photo: Fred Hutch

Education, Training, Board Certifications

  • M.D., University of Campinas, Brazil
  • Ph.D., University of Campinas
  • Residency in Internal Medicine, University of Campinas
  • Fellowship in Clinical Hematology and Transfusion Medicine, University of Campinas
  • Fellowship, National Heart, Lung, and Blood Institute, Bethesda

clinical expertise

  • Autoimmune diseases
  • Blood disorders
  • Essential thrombocytosis
  • Hemolytic anemias
  • Hereditary spherocytosis
  • Idiopathic thrombocytopenic purpura




Clinical and/or research interests

Dr. Kleber Yotsumoto Fertrin’s research aims to investigate novel potential approaches to treat and cure patients with hemolytic anemias, such as sickle cell disease and thalassemias, to reduce the need for blood transfusion, and to prevent and treat excess body iron.

Originally starting his career in Brazil, Dr. Fertrin’s early interest in genetics led him to study the clinical aspects and molecular biology of sickle cell disease and thalassemias, which are very prevalent in his home country, along with other rare anemias leading to the need for red blood cell transfusions and, consequently, to iron overload. His previous research reported on how iron metabolism regulation varies depending on the underlying defect in erythropoiesis (Fertrin et al., Am J Hematol 2014), and on the spectrum of tissue iron overload across different disorders, affecting most frequently the liver, but also more rarely the brain (Borges et al., Am J Neuropsych 2019) and the heart (Tavares et al., Transfus Med Rev 2019). In clinical research, he participated in the design and execution of the first clinical trials to demonstrate the effectiveness of adjuvant amlodipine to improve iron chelation in patients with transfusion-dependent thalassemia (Fernandes et al., Am J Med 2013 and Blood 2016) and participated in the multicenter clinical trial that led to the approval of crizanlizumab as treatment for recurrent vaso-occlusive crises in patients with sickle cell disease.

Dr. Fertrin’s current research projects explore novel medications that can reduce anemia and iron overload in pyruvate kinase deficiency and thalassemias, as well as decrease the frequency of painful episodes in sickle cell disease. He is also interested in the use of curative approaches for hemoglobin disorders, including gene editing, and in innovative therapeutic strategies that can mitigate the need for red blood cell transfusions more broadly or improve tissue iron removal in patients who develop iron overload.