The U.S. Food and Drug Administration has given Breakthrough Therapy Designation status to blinatumomab, a drug in development at Amgen Inc. for treating certain cancers. The Thousand Oaks pharmaceutical company said the designation resulted from a recent study on patients with acute lymphoblastic leukemia, a cancer of the blood and bone marrow. To qualify for breakthrough status, a drug must show the potential for significant improvement compared to available therapy options. Dr. Sean Harper, executive vice president of research and development at Amgen, said he expects to file an FDA application to commercialize blinatumomab by the end of the year. “There is a high unmet need for new medicines to treat relapsed and refractory acute lymphoblastic leukemia patients, who have very few treatment options,” he said in a statement. The FDA’s Breakthrough Therapy Designation expedites the agency’s review of a drug for serious or life-threatening conditions. In the U.S., more than 6,000 cases of acute lymphoblastic leukemia were diagnosed in 2013. In adult patients, average survival was three to five months. The company announced the breakthrough designation Tuesday. Shares closed Wednesday up 72 cents or less than 1 percent to $121.03 on the Nasdaq.