A Study of Elritercept to Treat Anemia in Adults With Very Low, Low, or Intermediate Risk Myelodysplastic Syndromes (MDS) Who Need Regular Blood Transfusions

The main aim of this study is to find out how well elritercept works in lowering the need for RBC transfusions. Other aims are to learn how well elritercept works in reducing the need for RBC transfusions over longer periods of time or in adults with high transfusion needs. The study will also check on how safe elritercept is and how well it is tolerated.

This is a Phase 3, double-blind, randomized, placebo-controlled study to evaluate the efficacy and safety of elritercept (TAK-226, KER-050) versus placebo. Elritercept (TAK-226, KER-050) is an investigational medicinal product being developed for the treatment of anemia in adult participants with a diagnosis of lower-risk myelodysplastic neoplasms/syndromes. After all required Screening Period assessments are completed, and eligibility is confirmed, participants will be randomized and enter the Primary Phase of the Double-Blind Treatment Period. Participants will be randomly assigned in a 2:1 ratio to receive either elritercept (TAK-226, KER-050) or placebo subcutaneously (SC) every 4 weeks (Q4W). Participants will be stratified according to their RS status (RS-positive versus non-RS) and baseline transfusion burden (LTB versus HTB). The Primary Phase of the Double-blind Treatment Period will last 24 weeks. The Secondary Phase of the Double-Blind Treatment Period will last an additional 24 weeks. During the Secondary Phase of the Double-Blind Treatment Period, all participants will continue to receive the same double-blind treatment they received during the Primary Phase. Study visits will occur approximately every 2 weeks from Cycle 1 through Cycle 6 and every 4 weeks from Cycle 7 through the remainder of the Double-Blind Treatment Period. During the Extension Phase of the Double-Blind Treatment Period, all eligible participants will continue to receive the same double-blind treatment they received during the Primary and Secondary Phases. Participants will continue in the Extension Phase until they individually discontinue or until the study is unblinded. For participants to remain on double-blind treatment, they must meet the criteria outlined in the MDS disease assessment criteria every 24 weeks. Based on the outcome of the Week 24 MDS disease assessment, participants will either continue in the Extension Phase of the Double-blind Treatment Period or will be discontinued from treatment and proceed to End of Treatment and then into the Safety Follow-up Period. The Safety Follow-Up Period will extend from the last dose of study treatment through 8 weeks after the last dose of study treatment. Study visits should occur every 4 weeks within the Safety Follow-Up Period. Long-term follow-up will take place quarterly after a participant has completed the Safety Follow-Up Period. Long-term follow-up will continue for 5 years from the first dose of study treatment or 3 years after the last dose, whichever is longer, or until a participant is deceased, is lost to follow-up, withdraws consent, or the study closes, whichever is earliest.