Talazoparib and Low-Dose Temozolomide in Treating Participants With Relapsed or Refractory Extensive-Stage Small Cell Lung Cancer

This phase II trial studies how effective talazoparib and temozolomide are for treating participants with extensive-stage small cell lung cancer that has come back after an initial chemotherapy treatment. Talazoparib, a PARP inhibitor, may stop the growth of tumor cells by preventing them from repairing their DNA. Chemotherapy, such as temozolomide, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving talazoparib and temozolomide may work better in treating participants with extensive-stage small cell lung cancer than either one alone.

PRIMARY OBJECTIVES: I. Evaluate the efficacy of talazoparib in combination with temozolomide as measured by objective response rate (ORR). SECONDARY OBJECTIVES: I. To evaluate the efficacy of talazoparib plus temozolomide as measured by progression-free survival (PFS), overall survival, duration of response, and time to response. II. To evaluate the safety, tolerability of talazoparib plus temozolomide. III. To evaluate the pharmacokinetics of talazoparib when given in combination with temozolomide. IV. To evaluate patient reported outcomes per the Patient Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). EXPLORATORY OBJECTIVES: I. To identify potential biomarkers associated with response to study drug treatment. OUTLINE: Participants receive temozolomide orally (PO) on days 1-5 and talazoparib PO once daily (QD) on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, participants are followed up at 30 days and then up to 1 year.