According to the Associated Press, Pfizer Inc. said that the Food and Drug Administration accepted its application for the experimental lung cancer treatment crizotinib, one of its key drug candidates. Pfizer said it also filed for approval in Japan, meaning it is now seeking approval in the world''s two largest pharmaceutical markets. Last year the FDA agreed to conduct a priority review of the drug, which would return a decision within six months instead of the usual 10 months. Pfizer is seeking approval of crizotinib as a treatment for advanced non-small cell lung cancer. Crizotinib is a pill, and it is the first of a new class of cancer drugs that appears to be less toxic than most chemotherapy. The FDA awarded orphan drug status to crizotinib, meaning Pfizer could get up to seven years of marketing exclusivity if the product is approved. Crizotinib targets a genetic variation that is found in about 4 percent of non-small cell lung cancer patients. The drug is designed to block signaling in cell pathways that are critical for tumor cell growth and survival.