ALK and non-small cell lung carcinoma: In the phase Ib study [59] of pembrolizumab plus crizotinib for previously untreated ALK-rearranged advanced NSCLC, one of the first two patients enrolled at dose level 0 (crizotinib 250 mg twice daily and pembrolizumab 200 mg every 3 weeks) required discontinuation of pembrolizumab due to grade 3 liver toxicity, and one died of grade 4 pneumonia induced by pembrolizumab.