Aaron Kesselheim is an associate professor of medicine at Harvard Medical School and a member of the Division of Pharmacoepidemiology and Pharmacoeconomics at Brigham and Women's Hospital. Stephen Morrissey, the interviewer, is the Managing Editor of the Journal. A. Sarpatwari, J. Avorn, and A.S. Kesselheim. Progress and Hurdles for Follow-on Biologics. N Engl J Med 2015;