Miltuximab®-IR700-mediated PIT was tested in prostate (DU-145), bladder (C3 and T-24), brain (U-87 and U-251) and ovarian (SKOV-3) cancer cell lines….Miltuximab®-IR700-mediated PIT caused 67.3–92.3% reduction in viability of cells with medium-high GPC-1 expression and did not affect the viability of GPC-1-low cells....After confirming the binding of Miltuximab® to a panel of GPC-1 expressing cancer cell lines, we conjugated it with IR700 and investigated PIT with Miltuximab®-IR700 conjugate in bladder, prostate, brain, and ovarian cancer cell lines, demonstrating effective cell killing that was specific, and dependent on GPC-1 expression.