Elritercept (KER-050 / TAK-226): A Comprehensive Profile

1. Introduction to Elritercept (KER-050 / TAK-226)

Elritercept, also identified by the development codes KER-050 and TAK-226, is an investigational therapeutic agent currently under clinical evaluation.[1] Structurally, it is engineered as a fusion protein. This protein combines a modified extracellular domain of the human activin receptor type IIA (ActRIIA) with the Fc (fragment crystallizable) region of human immunoglobulin G1 (IgG1).[3] Functionally, elritercept acts as a ligand trap, specifically modulating signaling pathways mediated by ActRIIA.[1] Its Chemical Abstracts Service (CAS) number is 2727114-26-1, and its FDA Unique Ingredient Identifier (UNII) is ZNC37E4KAK.[2]

The development of elritercept was initiated by Keros Therapeutics, Inc..[6] Recognizing its therapeutic potential, Takeda entered into a significant global license agreement with Keros, effective January 2025. This agreement grants Takeda exclusive rights for the development, manufacturing, and commercialization of elritercept worldwide, excluding mainland China, Hong Kong, and Macau.[1] The substantial upfront payment of $200 million from Takeda to Keros, coupled with potential future milestones, highlights the perceived value and strategic importance of elritercept within the hematology and oncology landscape.[1] This level of investment from a major pharmaceutical entity like Takeda suggests strong confidence in elritercept's potential, likely based on promising early-phase clinical data and its capacity to address significant unmet medical needs in its target indications. Takeda has explicitly identified elritercept as a key addition to its oncology pipeline and a potential driver for future growth.[7]