Last May, the Food and Drug Administration (FDA) approved Amgen and Novartis’ Aimovig, the first drug specifically designed to prevent chronic migraines, and offered new hope to the millions of Americans regularly weathering these debilitating headaches. Just months later came two other drugs in its class, Eli Lilly’s Emgality and Teva Pharmaceuticals’ Ajovy. About a year after Aimovig hit the market, patients and doctors are reporting dramatic successes thanks to these therapies.