Harpoon Therapeutics, Inc. (NASDAQ: HARP), a clinical-stage immunotherapy company developing a novel class of T cell engagers, today announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation for HPN217 for the treatment of multiple myeloma. HPN217, a tri-specific T cell activating recombinant protein construct (TriTAC®) targets B-cell maturation antigen (BCMA), a well-validated antigen expressed on malignant multiple myeloma cells. Harpoon has four drug product candidates in clinical development for the treatment of solid and hematologic malignancies based on its proprietary TriTAC platform.