Erenumab, which is being co-developed with Novartis, was tested at the 70 mg and 140 mg doses in a 12-week, 667-patient phase 2 study of subjects who were experiencing about 18 migraine days per month.
Patients experienced a 6.6-day reduction in monthly migraine days in each of the erenumab treatment arms, compared to a 4.2-day reduction in the placebo arm.
Amgen said the safety profile of erenumab was similar to placebo across both treatment arms and no adverse event was reported in over 5% of patients treated with erenumab.
The company is undertaking further analyses and plans to present the data at a future medical conference.
Amgen executive vice president of research and development Sean Harper said: "These positive results are exciting because they add to the growing body of evidence supporting erenumab for the prevention of migraine. We look forward to Phase 3 episodic migraine data later this year."
Erenumab is a fully human monoclonal antibody specifically targets the Calcitonin-Gene-Related-Peptide (CGRP) receptor, which is believed to transmit signals that can cause incapacitating pain.
Migraine is a primary headache disorder characterized by recurrent headaches that are moderate to severe.
In the US, between three and seven million Americans suffer from chronic migraine, with about 15 headache days a month with at least eight days being migraine.