Company: KROS
Filing Date: 2025-02-26
Form Type: 10-K
Source: 0001664710-25-000018
Chunk: 114

Company: Keros Therapeutics, Inc.
Filing Date: 2025-02-26
Form: 10-K
Item: Item 1
Chunk 114
---
ritercept can potentially promote production of platelets by blocking inhibitory TGF-ß ligands so that megakaryocytes can fully differentiate. Additionally, bone marrow analysis performed 24 hours post-dose demonstrated that administration of RKER-050 increased the megakaryocyte precursor population, and that these 

21

cells had increased ploidy, compared to vehicle. These data suggest that RKER-050 promoted the maturation of early megakaryocyte populations and primed megakaryocytes for proplatelet production.

•Reduced accumulation of progenitor cells. Ineffective hematopoiesis in patients with MDS and in patients with myelofibrosis can be caused by excessive production of blood cell progenitors that are unable to complete differentiation and ultimately become mature blood cells. We believe treatment with elritercept will stimulate these progenitors to progress to maturation, ameliorating the accumulation of these cells that lead to MDS- and myelofibrosis-associated cytopenias.

•Regeneration of the bone marrow microenvironment to potentially slow disease progression. The bone marrow microenvironment is composed of bone cells, stromal cells, immune cells, blood vessels and nerves. Crosstalk in this osteo-hematopoietic niche determines the maintenance, self-renewal and eventual differentiation of hematopoietic stem cells and progenitor cells to blood cells. Accordingly, a disease-impacted bone marrow microenvironment contributes to ineffective hematopoiesis and bone loss. In a preclinical study, administration of RKER-050 in a mouse model of MDS prevented the anemia and bone loss observed in the vehicle-treated MDS mice. We believe these data support the potential of elritercept to alter the bone marrow microenvironment that is supportive of self-renewal and maintenance of normal hematopoietic stem cells and progenitor cells in patients with MDS and other hematological diseases, including myelofibrosis.

▪Robust and sustained increase in red blood cells, hemoglobin and reticulocytes, supporting monthly or less frequent dosing. ESAs can require dosing up to three times a week. We believe that treatment with elritercept has the potential to reduce the frequency of dosing to every four weeks or less frequently, thereby decreasing the burden on patients and potentially improving compliance.

In December 2024, we entered into an exclusive license agreement with Takeda to further develop, manufacture and commercialize elritercept worldwide outside of mainland China, Hong Kong and Mac