About 40 million Americans suffer from migraine — intense headaches characterized by throbbing pain and sensitivity to light and nausea. The condition, which can last for days, is incurable.

Lilly's trial tested three doses of the oral drug against a placebo. Patients enrolled in the trial had an average of more than five migraine attacks per month.

At two hours following the first dose, a higher percentage of patients treated with lasmiditan were migraine pain-free compared to those on a placebo, meeting the study's main goal, the company said.

Indianapolis-based Lilly, which acquired lasmiditan through its $960 million purchase of CoLucid Pharmaceuticals in January, said it plans to file a U.S. marketing application for the drug in the second half of 2018.

Currently, migraine patients are treated with triptans, a class of drugs that hit the market in the 1990s. Triptans work by constricting blood vessels in the brain and cannot be used in up to 35 percent of patients due to high cardiovascular risk.

A host of other drugs - including anti-depressants, medicines for hypertension and even botox - are also used to treat migraine, but with little success.

Overall, migraine costs the United States about $36 billion annually in healthcare and lost productivity, according to the Migraine Research Foundation.

A clutch of drugmakers are racing to grab a piece of this lucrative, under-served market.

Lilly has another migraine drug in development, galcanezumab, which targets a protein associated with pain signaling called CGRP.

But unlike lasmiditan, galcanezumab is being evaluated as a treatment to prevent migraines in patients who suffer from a severe form of the disorder.

Companies including Amgen Inc, Teva Pharmaceutical Industries Ltd and Alder Biopharmaceuticals Inc are also developing similar CGRP drugs to prevent migraine.

Amgen submitted a U.S. application to market its migraine drug in May.