Amgen moved closer towards becoming the first company to gain an approval for a monoclonal antibody therapy to prevent migraine episodes. The Thousand Oaks, California, biotech announced positive top-line phase 3 data September 28, for erenumab, which blocks the calcitonin gene-related peptide (CGRP) receptor. In phase 3 studies, erenumab reduced the number of monthly migraine days by 2.9 days compared with 1.8 days in the placebo arm, measured over 12 weeks, meeting its primary endpoint. Participants in the study, called ARISE, had been experiencing 4–14 migraine days each month. The safety profile of erenumab was similar to placebo. ARISE is the first pivotal trial of erenumab. Amgen is collaborating on the drug's development with Basel-based Novartis, which holds commercialization rights outside of the US, Canada and Japan. They are competing with several other developers of CGRP-targeting migraine drugs; Alder Biopharmaceuticals, Eli Lilly and Allergan all have candidates that bind to CGRP ligand in phase 3 (Nat. Biotechnol. 33, 676, 2015). In June, Amgen also announced positive phase 2 results using erenumab to treat chronic migraine, a market comprising about 10% of migraine patients. Amgen may seek approval in one or more migraine indications in early 2018, says Leerink Swann analyst Geoffrey Porges—a faster timeline than for its competitors, who have yet to report phase 3 data. But analysts generally do not expect to see much difference in efficacy between these drugs. They will more likely be differentiated based on dosing format and/or frequency and tolerability versus current treatments, Porges and other Leerink analysts said in a note this past summer.