Amgen’s migraine drug Aimovig continues to impress with its efficacy in late-stage studies. On Monday, the company revealed Phase IIIb data that demonstrated the drug is also effective in reducing the number of episodic headaches in patients who have not responded to previous treatments.

The new data was released three months after Amgen and its development partner Novartis announced Phase III results that showed Aimovig (erenumab) significantly reduced the number of “mean monthly migraine days” for patients. In November 2017, Amgen said those patients were likely to see the number of migraines experienced in a month cut by 50 percent.

Shares of Amgen climbed steadily following the report to close at $192.33 on Monday. Shares are up slightly this morning to $193.38.

Migraines impact about 12 percent of the population in the United States, including children. The pain and other symptoms associated with migraines can cause sufferers to completely stop what they are doing and prevent them from working or functioning in a normal capacity for more than a day. Episodic migraine sufferers typically deal with four to 14 migraine days per month.

This morning, Amgen said its Phase IIIB Liberty study showed that patients who had experienced two to four previous preventive treatment failures met primary endpoints. In the Liberty study, 246 patients were randomized to receive Aimovig or placebo over a 12-week treatment phase. Amgen said significantly more patients taking Aimovig experienced at least a 50 percent reduction in monthly migraine days compared to placebo. Additionally, the trial met secondary endpoints including reduction of monthly migraine days, reduction in days needing acute (rescue) medication, improvement in scores on the Migraine Physical Function Impact Diary (MPFID) tool. Aimovig also yielded 75 percent and 100 percent responder rates, which means the number of patients experiencing at least a 75 percent or 100 percent reduction in monthly migraine days compared to placebo.

Amgen said the Phase IIIb results are the first “positive placebo-controlled data ever reported” in an episodic patient population that is made entirely of patients who have failed two to four preventive medications.

"We've purposely designed a clinical program for Aimovig that examined a broad spectrum of migraine patients, ranging from those who have never tried a preventive treatment to patients who have tried and failed such treatments," Sean Harper, Amgen’s head of Research and Development, said in a statement. "These data in patients with multiple treatment failures, who are not only considered difficult to treat but also have few options available, add to the consistent body of evidence for Aimovig.”

The Phase IIIb news puts Amgen one step closer to bringing its calcitonin gene-related peptide (CGRP) receptor drug to market for migraine headaches. The U.S. Food and Drug Administration has set a Prescription Drug User Fee Act date of May 17 for Aimovig.

Rival drugmaker Teva Pharmaceuticals is expecting the U.S. Food and Drug Administration to rule on its CGRP migraine treatment fremanezumab by the end of June. The FDA accepted that company’s Biologics License Application on Dec. 15.

If approved, Amgen’s Aimovig will be administered once-monthly using a self-injection device. Novartis and Amgen will co-commercialize Aimovig in the U.S. Novartis will commercialize the drug globally except in Japan, where Amgen has rights.