CD274 and small cell lung carcinoma: They randomized patients with extensive SCLC, unselected for PD-L1, and controlled brain metastases who detained an objective response after 2 cycles of chemotherapy with platinum and etoposide to receive pembrolizumab in combination with four additional cycles of platinum etoposide then pembrolizumab up to 35 cycles (experimental arm) vs. four additional platinum etoposide cycles (control arm).