Polyphor AG announced that due to the lack of meaningful clinical benefit based on objective response rate (ORR) and clinical response rate (CBR) in the third-line or later population and following a thorough analysis, the company has decided to initiate the closure of the FORTRESS study evaluating balixafortide (POL6326) in combination with eribulin for the treatment of patients with HER2-negative, locally recurrent or metastatic breast cancer. As data maturity is reached for the overall population, Polyphor plans to further analyze progression-free survival (PFS) data for the trial, including all major subgroups. However, the company will not seek an overall survival (OS) analysis as key secondary endpoint nor marketing approval in connection with this study. The company plans to present the data from the FORTRESS trial results analyses at a future medical meeting. In order to reduce costs and increase operational efficiency, Polyphor plans to restructure by up to 29 positions. The consultation process with employees has already been initiated.