The Food and Drug Administration approved a new migraine drug on Thursday.

Aimovig, known generically as erenumab, is the first drug in a new class of headache medicines. It's been shown to stop migraine headaches before they start.

The drug would be approved for patients who have tried other drugs and found no relief. In studies, it did not entirely prevent migraines, but reduced their frequency.

“Aimovig provides patients with a novel option for reducing the number of days with migraine,” said Dr. Eric Bastings, deputy director of the FDA's neurology products division.

“We need new treatments for this painful and often debilitating condition.”

FDA's approval means the drug may soon be available under prescription. It should also be paid for by health insurance.

The drug's maker, Amgen, said U.S. list price is for the once monthly self-injection treatment will be $575 per month or $6,900 annually.

“The price of Aimovig reflects the value it brings to patients and society, including the financial impact on sufferers, caregivers and employers, while also factoring in critical issues such as patient affordability, and fair and timely access,” Amgen said in a statement.

Erenumab the first in a new class of drugs that block calcitonin gene-related peptide (CGRP), a molecule that transmits migraine pain signals during an attack. It's a human monoclonal antibody -- a targeted immune system protein.

It's formulated as an injection to provide long-lasting protection.

More than 39 million Americans suffer from migraine attacks, according to the Migraine Research Foundation. Of these, about 4 million have chronic migraine and suffer headaches for 10 to 14 days a month.

While some people are helped by low cost, over-the-counter drugs such as ibuprofen, others need prescription medications, such as sumatriptan and ergotamine, which constrict the blood vessels in the brain and can cause dizziness or nausea. Botox injections are also used to help ease migraines in some people.

But a large percentage of sufferers are not helped by anything.

"This is the first-ever mechanism specific migraine drug designed for prevention," said Dr. Peter Goadsby, professor of neurology at Kings College London and the University of California, San Francisco, who is a lead researcher on the drug. "This will change migraine treatment for those who don’t respond to conventional treatments."

Goadsby's team found that the drug reduced the average number of monthly migraine headaches by more than 50 percent for nearly half of study participants. After three months, patients treated with the human antibody were nearly three times more likely to have reduced their migraine days by 50 percent or more than those treated with placebo.

Participants of the study also had a greater average reduction in the number of days with headaches and the number of days they needed to take drugs to stop the migraines.

No patients taking erenumab stopped treatment due to adverse side effects, but the scientists noted that more research will needed to investigate if the benefits continue.

Malden, Massachusetts native Denise Desjardins, 58, with niece Madeline Salvitella suffered from migraine headaches for over 10 years, but found great relief after taking erenumab, a fully human monoclonal antibody drug that is showing great promise in migraine prevention. Denise Dejardins

Malden, Massachusetts native Denise Desjardins, 58, coped with migraine headaches for more than 10 years, particularly around her menstrual cycle.

“I would land in bed for two to three days, four to five times a year,” said Desjardins. “These were in-your-bed, no-matter-what headaches.”

Her migraines became a daily misery after a bilateral mastectomy following a diagnosis of breast cancer. She was put on Imitrex, a popular migraine drug that helps to quiet overactive pain nerves in the brain, but it didn't help.

For about four years, Desjardins has been taking an erenumab injection once a month, without any side effects, as part of the study.

"I don't even think I get migraines anymore," said Desjardins.

“I think having a treatment that is specifically invented to treat a disease that affects millions of people, makes this a big game changer,” said Dr. Dario Zagar, president of Associated Neurologists of Southern Connecticut.

Because other migraine medications were not developed for headache, their side effects limited how well patients could tolerate them.

“I think someone who gets migraines, will tell you they would do just about anything to reduce how frequently they're getting them — and if you told someone who was getting migraines two or three times a week that they would only get one (a week) or possibly none at all — they would be very happy,” said Zagar.