Many patients with non-small cell lung cancer (NSCLC) who have mutations in the ALK gene benefit from treatment with ALK inhibitors. A phase I/II clinical trial of the new ALK inhibitor CH5424802 determined that the drug was well tolerated and showed signs of effectiveness. Out of 46 patients with ALK-mutant advanced NSCLC, 2 experienced a complete response and 41 a partial response; 40 patients currently remain on the treatment. If future studies confirm the effectiveness of CH5424802, it could offer an additional option to crizotinib (Xalkori), currently the only ALK inhibitor approved for treating ALK-mutant NSCLC. An ongoing clinical trial is investigating whether CH5424802 is beneficial in patients who have become resistant to Xalkori.