A new migraine medication – one of the first bespoke drugs for decades – appears to work well even when others have failed, researchers have said .
Erenumab is a monthly injection that might soon be offered to patients on the NHS if the cost can be justified.
The latest findings presented at a US medical conference suggest it could help about a third of people with intractable migraine.
Up to four other treatments had failed to prevent their pain.
Erenumab reduced the average number of monthly migraine headaches by more than 50% for nearly a third of the people with hard-to-treat migraine who took part in the 12-week study.
The drug works differently from other preventive ones given to migraine patients, which are often "repurposed" medicines originally designed to treat other conditions, such as blood pressure and epilepsy, rather than severe headache.
Erenumab, like three other monoclonal antibody drugs also being tested by pharmaceutical companies, is tailor-made for migraine.
It takes advantage of the body's protective immune system to block the nerve signals that cause migraine pain.
More than a headache
Migraine is very common – it affects one in seven British people – and can be hard to stop.
The severe throbbing pain can last for hours or days on end, making it difficult to work, rest and sleep.
Some people get nauseous and sick with it. Others also get an aura – accompanying visual symptoms, such as seeing colourful shapes or experiencing tunnel vision or blind spots.
Rachel Walls, 37, from the West Midlands, has had migraines since she was 17. For the past two decades she has tried lots of different preventive medications and alternative therapies with no success.
"I get a migraine with aura so it affects my eyesight too," she says. "I see cells floating across my vision and I find smells and strong light really difficult to deal with.
"The pain is horrible. It's like having your skull crushed. You can't do anything else – just lie in a dark room and wait for it to go, and it can last for days."
She relies on strong painkillers during these attacks, which she says is unpleasant.
She took part in the erenumab study and says her attacks are now fewer, shorter and less intense.
"I get about six or eight migraine attacks a month now, whereas before it was 12 to 15.
"It's not a miracle drug – but for me, it has made a difference. I started the trial last June. For the first three months I didn't know if I was given the drug or a dummy one, but since then I have been on it.
"I've been told that I can only have it for 12 months though, so I'll have to come off it soon and wait to see if it's approved before I can get it again."
Experts hope the new monoclonal antibody treatments could prove life-changing for many of the millions of people living with migraine, but longer trials are still needed to show this.
Dr Peter Goadsby, one of the lead investigators of the study and an expert neurologist at University College London, said: "Our challenge now is to work out who is going to benefit the most from them at the get-go.
"It's really promising that it can help some of these patients who, until now, have not had an option."
Simon Evans, of Migraine Action, said: "An option that can prevent migraine and that's well tolerated is sorely needed.
"Migraine is too often trivialised as just a headache when, in reality, it can be a debilitating, chronic condition that can destroy lives."
Erenumab and another monoclonal antibody migraine treatment called fremanezumab have been submitted for approval by US and European drug regulators. A decision is expected soon.