The murine IgG2a antibody MOv19 was generated by hybridoma technology in the late 1980s, using the crude membrane of an ovarian cancer cell line as immunogen.57 Both MOv19 and LK26, the original mouse clone of falertuzumab, recognized overlapping FRα epitopes with high affinity.58 The murine constant regions of MOv19 (γ2a, κ) were replaced with human CL (κ) and CH (γ1) to generate the chimeric antibody ChiMOv19, which exhibited similar or superior ADCC activity than its murine counterpart.59 Subsequently, a humanized derivative of MOv19 (denoted M9346A) was generated. Here, FOLR1 is linked to ovarian cancer.