The gist: Genetic mutations in a patient’s tumor can help determine which drugs are more likely to work. But a tumor can sometimes develop a new genetic mutation that makes it stop responding to a particular drug. When a person becomes resistant to his or her treatment, knowing about any new tumor mutations can help determine which treatment to try next. A recent study looked at mutations in non-small cell lung cancer (NSCLC). Different kinds of mutations in a gene called ALK can make NSCLC tumors treatable with different drugs. Certain ALK mutations make NSCLC tumors resistant to certain drugs. The scientists identified two new mutations that are associated with resistance to the drugs crizotinib and alectinib. Based on the findings, they suggest that a patient should get tested for new tumor mutations each time he or she becomes resistant to a particular drug. This will allow the doctor to select the best-fitting treatment to try next.
“Two novel ALK mutations, V1180L and I1171T, were associated with resistance to crizotinib and alectinib but were sensitive to other next-generation ALK tyrosine kinase inhibitors for non–small-cell lung cancer, according to study results.
“Although crizotinib (Xalkori, Pfizer) is the standard therapy for ALK-rearranged non–small cell lung cancer (NSCLC), patients often develop resistance to this agent and the next-generation ALK tyrosine kinase inhibitor (TKI) alectinib (CH5424802/RO5424802; Chugai Pharmaceuticals, Roche), according to study background information…
“ ‘These data highlight the need for repeat tumor biopsies at the time of resistance to each individual agent to determine if ALK mutations are present in the tumor, and if so, which ones,’ Politi and Gettinger wrote. ‘This practice will allow subsequent treatment to be tailored to the most current mutational state of the tumor.’ ”