In this presentation, Joshua Bauml, MD, explains the difficulty of targeted therapies for small cell lung cancer—a disease for which no key driver mutation has been identified—and describes studies at Penn Medicine involving the alternative targets PARP1, a “proofreading” protein, and DLL3, an abnormal cell surface receptor, both of which are over-expressed in small cell lung cancer. Dr. Bauml notes the success of a new therapy, rovalpituzumab tesirine, that binds to DLL3 to release a cell-specific chemotherapy.