Learn about biosimilars biosimilars: What is a Biosimilar? A biosimilar is a type of biologic medication. The term “biosimilar” means that the medication is highly similar to the already approved brand name biologic (“originator” medication). Biosimilars are not generic versions of the original biologic. Difference Between… , biosimilar medications, and their use for bone marrow failure bone marrow failure: A condition that occurs when the bone marrow stops making enough healthy blood cells. The most common of these rare diseases are aplastic anemia, myelodysplastic syndromes (MDS) and paroxysmal nocturnal hemoglobinuria (PNH). Bone marrow failure can be acquired (begin any time in life) or can be… disease treatments from Cate Lockhart, MS, PharmD, PhD.