Company: KROS
Filing Date: 2025-02-26
Form Type: 10-K
Source: 0001664710-25-000018
Chunk: 113

Company: Keros Therapeutics, Inc.
Filing Date: 2025-02-26
Form: 10-K
Item: Item 1
Chunk 113
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 anywhere along the differentiation and maturation spectrum of erythropoiesis, and often have multiple mutations that cause ineffective erythropoiesis. By acting on cell types throughout the erythropoiesis pathway, elritercept may lead to robust responses in RS positive patients who have a characteristic defect in terminal maturation, and may also address anemia in the broader MDS population, including non-RS patients, that has defects in earlier-stage erythroid cell development. Specifically related to red blood cells, we have demonstrated in multiple preclinical studies that administration of RKER-050 elicited increases in red blood cell production in healthy mice by stimulating multiple stages in the maturation of erythroid precursors. The rapid and sustained increase in red blood cells observed in these preclinical studies suggests that RKER-050 potentially stimulated both terminal maturation of late-stage erythroid precursors to rapidly increase red blood cells and maturation of early-stage precursor populations to increase the pool of progenitors that can be mobilized for a sustained upregulation of erythropoiesis. Additionally, by increasing the pool of early erythroid precursor cells and serum erythropoietin, we believe elritercept can potentially treat patients with MDS that have hypocellular bone marrow. We have also observed an increase in erythropoietin in healthy mice in preclinical studies of RKER-050, which we believe could contribute to the durability in red blood cell production and is supportive of the durability of the red blood cell increase we observed in our Phase 1 clinical trial of elritercept in healthy post-menopausal women.

•Increased platelet counts in blood. Ineffective hematopoiesis in patients with MDS and in patients with myelofibrosis can result in thrombocytopenia, which can lead to an increased risk of bleeding events. We believe treatment with elritercept has the potential to address the MDS- and myelofibrosis-associated thrombocytopenia. Additionally, by promoting thrombopoiesis, we believe elritercept has the potential to aid the differentiation of megakaryocytes to platelets in myelofibrosis patients and reactivate hematopoiesis in the bone marrow. We have demonstrated in preclinical studies that treatment with a single dose of RKER-050 resulted in rapid and sustained increases in platelets in healthy mice. We observed an increase in platelets 12 hours after administration of RKER-050, which we believe supports that el