MERU

Inclusion Criteria:

- Histologically or cytologically confirmed extensive-stage disease small cell lung
cancer (ED SCLC) at initial diagnosis with ongoing clinical benefit (stable disease
[SD], partial response [PR], or complete response [CR]) following completion of 4
cycles of first-line platinum-based therapy

- Participant is eligible to be randomized at least 3 but no more than 9 weeks from Day
1 of the fourth cycle of first-line platinum-based chemotherapy.

- Participants with a history of central nervous system (CNS) metastases prior to the
initiation of first-line platinum-based chemotherapy must have received definitive
local treatment and have documentation of stable or improved CNS disease status

- Eastern Cooperative Oncology Group (ECOG) performance score of 0 or 1

- Participants must have adequate bone marrow, renal and hepatic function

- Availability of archived or representative tumor material for assessment of DLL3
expression

Exclusion Criteria:

- Any prior systemic chemotherapy, small molecule inhibitors, immune checkpoint
inhibitors, other monoclonal antibodies, antibody-drug conjugates,
radioimmunoconjugates, T-cell or other cell-based or biologic therapies, or any other
anti-cancer therapy than that described in inclusion criteria for SCLC.

- Any disease-directed radiotherapy (except prophylactic cranial irradiation, palliative
radiotherapy to a radiographically documented non-progressing lesion for symptom
control, or pre-planned radiotherapy for CNS metastases present prior to start of
first-line therapy and non-progressing) after last dose of first-line chemotherapy.

- Prior exposure to a pyrrolobenzodiazepine (PBD-based) or indolinobenzodiazepine-based
drug, prior participation in a rovalpituzumab tesirine clinical trial, or known
hypersensitivity or other contraindications to rovalpituzumab tesirine or excipient
contained in the drug formulation.