Efficacy Endpoints in Migraine Clinical Trials: The Importance of Assessing Freedom from PainP14Silberstein, S.Marmura, M.Nahas, S. J.Newman, L.Farr, S.Author information1Jefferson Headache Center, Philadelphia, PA, USA; 2The Headache Institute, New York, NY, USA; 3Zogenix, Inc, Emeryville and San Diego, CA, USA.Headache 52(5):p 877-878, May 2012.Copyright © 2012 Blackwell Publishing Ltd.