Humans have suffered from migraines for millennia. Yet, despite decades of research, there isn't a drug on the market today that prevents them by targeting the underlying cause. All of that could change in a few months when the Food and Drug Administration is expected to announce its decision about new therapies that have the potential to turn migraine treatment on its head.The new therapies are based on research begun in the 1980s showing that people in the throes of a migraine attack have high levels of a protein called calcitonin gene–related peptide, or CGRP, in their blood.

              Step by step, researchers tracked and studied this neurochemical's effects. They found that injecting the peptide into the blood of people prone to migraines triggers migraine-like headaches, whereas people not prone to migraines experienced, at most, mild pain. Blocking transmission of CGRP in mice appeared to prevent migraine-like symptoms. And so a few companies started developing a pill that might do the same in humans.

               What's Triggering Your Migraine? Clinical trials of the first pills were effective against migraine but halted in 2011 over concerns about potential liver damage. So, four pharmaceutical companies rejiggered their approach. To bypass the liver, all four instead looked to an injectable therapy called monoclonal antibodies — tiny immune molecules most commonly used to treat cancer. Not only do these bypass the liver to block CGRP, but one injection appears to be effective for up to three months with almost no noticeable side effects.

                  Two manufacturers, Amgen (in collaboration with Novartis) and Teva Pharmaceuticals, have completed clinical trials and expect to hear from the FDA by June whether the therapies have been approved. Two more companies, Eli Lilly and Alder Biopharmaceuticals, plan to file for FDA approval later this year.