Oncology experts from multiple countries collaborated on the SELECT-1 randomized clinical trial, which focused on treatment of KRAS-mutant advanced non-small cell lung cancer (NSCLC). Screening patients in 25 countries from October 2013–January 2016, they enrolled individuals whose advanced disease continued to progress after first-line anticancer therapy. Participants were randomly assigned to treatment with docetaxel plus the mitogen-activated protein kinase inhibitor selumetinib or to treatment with docetaxel plus placebo. The final analysis included 251 patients in the selumetinib arm and 254 in the placebo group. By June 2016, 88% of the 510 participants had experienced a progression event and 68% had died. Progression-free survival, the primary outcome, was a median 3.9 months for the selumetinib cohort and 2.8 months for the remaining patients. Overall survival was a median 8.7 months and 7.9 months, respectively. Not only did the addition of selumetinib to docetaxel fail to improve survival rates in patients with KRAS-mutant advanced NSCLC, the investigators conclude, but patients in the selumetinib group experienced grade 3 or worse adverse events at a significantly higher rate than docetaxel-only patients.