Trilaciclib (G1T28), a CDK 4/6 Inhibitor, in Patients With Previously Treated Extensive Stage SCLC Receiving Topotecan Chemotherapy

Inclusion Criteria:

- Male or female subjects aged ≥18 years

- Unequivocally confirmed diagnosis of SCLC by histology or cytology, preferably
including the presence of neuroendocrine features by immunohistochemistry

- Progression during or after prior first- or second-line chemotherapy and eligible to
receive topotecan therapy

- At least 1 target lesion that is measurable by RECIST, Version 1.1

- Eastern Cooperative Oncology Group (ECOG) performance status of 0 - 2

- Adequate organ function

Exclusion Criteria:

- Presence of symptomatic brain metastases requiring immediate treatment with radiation
therapy or steroids.

- Uncontrolled ischemic heart disease or uncontrolled symptomatic congestive heart
failure

- Known history of stroke or cerebrovascular accident within 6 months prior to
enrollment

- Other uncontrolled serious chronic disease or conditions that in the investigator's
opinion could affect compliance or follow-up in the protocol

- Concurrent radiotherapy to any site or radiotherapy within 2 weeks prior to enrollment
or previous radiotherapy to the target lesion sites (the sites that are to be followed
for determination of a response)

- Receipt of any investigational medication within 2 weeks prior to enrollment

- History of topotecan treatment for SCLC