Inclusion Criteria:
1. Adult aged 18 years or older
2. Histologically confirmed SCLC with documented disease progression after at least 2 prior systemic regimens, including at least one platinum-based regimen
3. DLL3-expressing SCLC based on central immunohistochemistry (IHC) assessment of banked or otherwise representative tumor tissue. Positive is defined as staining in ≥ 1% of tumor cells
4. Measurable disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1
5. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
6. Minimum life expectancy of at least 12 weeks
7. Subjects with a history of central nervous system (CNS) metastases must have documentation of stable or improved status based on brain imaging for at least 2 weeks after completion of definitive treatment and within 2 weeks prior to first dose of study drug, off or on a stable dose of corticosteroids
8. Recovery to Grade 1 of any clinically significant toxicity (excluding alopecia) prior to initiation of study drug administration
9. Adequate hematologic and organ function as confirmed by laboratory values
10. Last dose of any prior therapy administered by the following time intervals before the first dose of study drug:
* Chemotherapy, small molecule inhibitors, radiation, and/or other investigational anticancer agents (excluding investigational monoclonal antibodies): 2 weeks
* Immune-checkpoint inhibitors (i.e., anti-PD-1, anti-PD-L1, or anti-CTLA-4): 4 weeks
* Other monoclonal antibodies, antibody-drug conjugates, radioimmunoconjugates, or T-cell or other cell-based therapies: 4 weeks (2 weeks with documented disease progression)
11. Females of childbearing potential must have a negative beta human chorionic gonadotropin (β-hCG) pregnancy test result within 7 days prior to the first dose of study drug. Females of non-childbearing potential are those who are postmenopausal greater than 1 year or who have had a bilateral tubal ligation or hysterectomy.
Exclusion Criteria:
1. Any significant medical condition, including any suggested by screening laboratory findings that, in the opinion of the investigator or sponsor, may place the subject at undue risk from the study, including but not necessarily limited to uncontrolled hypertension and/or diabetes, clinically significant pulmonary disease (e.g., chronic obstructive pulmonary disease requiring hospitalization within 6 months) or neurological disorder (e.g., seizure disorder active within 6 months)
2. 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 (NYHA) Class III-IV within 6 months prior to their first dose of study drug
3. Recent or ongoing serious infection, including:
* Any active grade 3 or higher (per National Cancer Institute's Common Terminology Criteria for Adverse Events \[NCI CTCAE\] version 4.03) viral, bacterial, or fungal infection within 2 weeks of the first dose of the study drug. Routine antimicrobial prophylaxis is permitted.
* Known seropositivity for or active infection by human immunodeficiency virus (HIV)
* Active Hepatitis B (by surface antigen expression or polymerase chain reaction) or C (by polymerase chain reaction) infection or on hepatitis-related antiviral therapy within 6 months of first dose of study drug.
4. Women who are breastfeeding
5. Systemic therapy with corticosteroids at \>20 mg/day prednisone or equivalent within 1 week prior to the first dose of study drug
6. History of another invasive malignancy that has not been in remission for at least 3 years. Exceptions to the 3 year limit include nonmelanoma skin cancer, curatively treated localized prostate cancer, and cervical cancer in situ on biopsy or squamous intraepithelial lesion on pap smear
7. Prior exposure to a pyrrolobenzodiazepine (PBD)-based drug, or known hypersensitivity to rovalpituzumab tesirine or excipient contained in the drug formulation, unless undergoing retreatment with rovalpituzumab tesirine in the context of this protocol
