Pfizer Terminates Phase II Maplirpacept Trial Amid Recruitment Struggles, Keeps Focus on Blood Cancer Pipeline
SHERIDAN, WYOMING – July 1, 2025 – Pfizer has announced the termination of its Phase II trial evaluating the investigational CD47-targeting fusion protein maplirpacept in diffuse large B-cell lymphoma (DLBCL), citing persistent recruitment difficulties that prevented the study from meeting enrollment targets. The decision, which affects a program inherited through the company’s $2.26 billion acquisition of Trillium Therapeutics in 2021, underscores ongoing challenges in advancing CD47 inhibitors while highlighting Pfizer’s continued commitment to its hematologic oncology pipeline.
Recruitment Roadblocks Halt Mid-Stage Development