RRx-001 Sequentially With a Platinum Doublet or a Platinum Doublet in Third-Line or Beyond in Patients With Small Cell Lung Cancer

1. Age ≥ 18 and \< 80 years 2. Prior platinum treatment is required 3. Prior treatment with a checkpoint inhibitor is required unless contraindicated. Maintenance with a checkpoint inhibitor is NOT required 4. Patient must have received at least 2 prior lines of therapy 5. Biopsy confirmation of small cell lung cancer 6. Capable of providing informed consent and complying with trial procedures 7. Measurable disease by RECIST 1.1. Measurable lesions will be confirmed by imaging (CT scan) 8. PS 0-1

1. Symptomatic central nervous system metastases or neurologically unstable patients that are on increasing steroid dose. 2. The presence of another primary malignancy (excluding in situ of the cervix or basal carcinoma of the skin) 3. Treatment of SCLC with any antineoplastic agent with the exception of steroids. 4. Patients with clinically significant illnesses which would compromise participation in the study, including, but not limited to active or uncontrolled infection, immune deficiencies, Hepatitis B, Hepatitis C, uncontrolled diabetes, uncontrolled hypertension, certain heart conditions, or mental illness/social situations that would limit compliance with study requirements. 5. History of an allergic reaction to previously received platinum-based regimen, or history of having to discontinue previously received platinum-based regimen secondary to toxicity (excluding hematologic toxicity) 6. Any clinical laboratory findings, which give reasonable suspicion of a disease or condition that contraindicates the use of any study medication or renders the patient at high risk from treatment 7. Uncontrolled or symptomatic pleural or pericardial effusion 8. Pregnant or nursing. There is a potential for congenital abnormalities and for this regimen to harm nursing infants