This phase III study is comparing the effectiveness of two types of immunotherapy treatments (MK-7684A and atezolizumab) when used in combination with chemotherapy (etoposide and carboplatin or cisplatin) in people with Extensive-Stage Small Cell Lung CancerA Phase 3, Randomized, Double-Blind Study of MK-7684A in Combination With Etoposide and Platinum Followed by MK-7684A vs Atezolizumab in Combination With Etoposide and Platinum Followed by Atezolizumab for the First-Line Treatment of Participants With Extensive-Stage Small Cell Lung Cancer

Summary

Eligible participants will be randomly allocated to either the Experimental Arm or the Active Comparator Arm. In the Experimental Arm, participants will receive 4 cycles (each cycle is 3 weeks) of a fixed-dose coformulation of 200mg pembrolizumab and 200mg vibostolimab (also known as MK7684A) every 3 weeks, in combination with 100mg/m^2 etoposide, and platinum chemotherapy (Area Under the Curve [AUC] 5 mg/mL/min carboplatin or 75mg/m^2 cisplatin)every 3 weeks for a total of approximately 12 weeks. This will then be followed by additional cycles of MK7684A every 3 weeks. In the Active Comparator Arm, participants will receive 4 cycles (each cycle is 3 weeks) of 1200mg atezolizumab every 3 weeks, in combination with 100mg/m^2 etoposide and platinum chemotherapy (AUC 5mg/mL/min carboplatin or 75mg/m^2 cisplatin) every 3 weeks for a total of approximately 12 weeks. This will then be followed by additional cycles of atezolizumab every 3 weeks.