A Study of IBI110 in Combination With Sintilimab and Chemotherapy in Patients With Untreated Extensive-Stage Small Cell Lung Cancer

Carboplatin will be administered after completion of Sintilimab by IV infusion to achieve an initial target AUC of 5 mg/mL/min on Day 1.

Cisplatin 75 mg/m\^2 will be administered after completion of Sintilimab by IV infusion on Day 1.

Etoposide 100 mg/m\^2 will be administered by IV infusion following carboplatin or cisplatin administration, during the induction phase on Day 1 through 3 of each cycle. On Days 2 and 3, patients will receive etoposide alone.

Sintilimab 200 mg will be administered by IV infusion following IBI110 on Day 1 of each 21-day .

IBI110 RP2D will be administered by IV infusion on Day 1 of each 21-day .