Although complex, biologic agents are key components of modern therapy in multiple disciplines, particularly oncology. However, despite the fact that biosimilars (eg, filgrastim-sndz, bevacizumab-awwb, trastuzumab-dkst, rituximab-abbs) have been approved in the United States, many clinicians are poorly informed about their unique pathway for approval. At the NCCN 2019 Annual Congress: Hematologic Malignancies, Dr. Andrew D. Zelenetz, Memorial Sloan Kettering Cancer Center, outlined important issues regarding the use of biosimilars, including extrapolation, interchangeability, and naming.