Cobimetinib is an oral inhibitor of MEK, a signaling protein that can cause some types of lung cancer to grow. Cobimetinib is also made by Genentech. Laboratory studies suggest that ALK and MEK may work together to help ALK+ lung cancer cells grow. In the laboratory, combination treatment with drugs targeting ALK and MEK prevented lung cancer cells from growing. It is possible that combination treatment with alectinib and cobimetinib will work better than alectinib alone to control the spread of the cancer.