Study Comparing Rovalpituzumab Tesirine Versus Topotecan in Subjects With Advanced or Metastatic Small Cell Lung Cancer With High Levels of Delta-like Protein 3 (DLL3) and Who Have First Disease Progression During or Following Front-line Platinum-based Chemotherapy (TAHOE)

* Participant must have histologically or cytologically confirmed advanced or metastatic Small Cell Lung Cancer (SCLC) with documented first disease progression during or following front-line platinum-based systemic regimen * Tumor must have high Delta-like protein 3 (DLL3) expression defined as having ≥ 75% tumor cells staining positive according to the VENTANA DLL3 (SP347) IHC Assay. * Participant must have measurable disease, as defined per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. * Participant must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Participant must have recovery to Grade 0 or 1 of any clinically significant toxicity (excluding alopecia) prior to initiation of study drug administration.

* Participant has a documented history of a cerebral vascular event (stroke or transient ischemic attack), unstable angina, myocardial infarction, or cardiac symptoms consistent with New York Heart Association Class (NYHA) III - IV within 6 months prior to their first dose of study drug. * Participant has known leptomeningeal metastases. * Participant has received more than one prior systemic therapy regimen for SCLC. * Participant had a serious infection within 2 weeks prior to randomization, including any Grade 3 or higher viral, bacterial, or fungal infection. * Participant has a history of active malignancies other than SCLC within the past 2 years prior to study entry, with the exception of in situ cancer which was curatively treated. * Participant had prior exposure to topotecan, irinotecan or any other topoisomerase I inhibitors.