Safety and Tolerability Evaluation of Low-dose Radiation in Combination With CS1001 in Relapsed SCLC Patients

This is a dose-escalation study of Low-dose Radiation in combination with CS1001 in relapsed SCLC patients. Patients are assigned to 3 treatment groups received from 3 Gy to 15Gy, to determine the safety, tolerability and the maximal tolerant dose. Biomarkers and immunological markers are collected and analyzed as well.

Inclusion criteria

• Patients with histologically or cytologically confirmed LS-SCLC or ES-SCLC and experienced progression since first-line standard platinum containing dual-drug chemotherapy.
• Patients whose initial diagnosis was limited must undergo radical chest radiotherapy and the time of tumor progression is not less than 3 months from the end of radiotherapy, or cannot receive radical chest radiotherapy due to specific reasons
• At least one extracranial measurable lesion (RECIST v1.1), and for a lesion that has received radiotherapy, progression of the lesion after radiotherapy must be confirmed.
• Patients with brain metastases are allowed to receive previous radiotherapy and their condition is stable, but the time to the end of radiotherapy must not be less than 3 months.
• No radiotherapy contraindications were judged by the radiologist
• ECOG performance status of 0 or 1.
• Patients with life expectancy ≥ 3 months.
• Patients must have adequate organ function.
• Fertile men and women of childbearing potential must agree to use an effective method of birth control from providing signed consent and for 6 months after last study drug administration.

Exclusion criteria

• Subjects known to have primary CNS tumors or meningeal metastases or unstable CNS metastases.
• Patients with active autoimmune diseases or history of autoimmune diseases should be excluded.
• Patients who have received immune checkpoint proteins/antibody/medicine (including PD-1, PD-L1, etc) for treatment.
• Known history of HIV infection.
• Subjects with active chronic hepatitis B or active hepatitis C .
• Patients who have serious hypersensitive reaction to monoclonal antibodies, and have history of uncontrolled allergic asthma.
• Known history of alcoholism or drugs abuse.
• Subjects with history of radiation pneumonitis of grade 3 or above, regardless of recovered or not.