Conflict of interest: A.H. Morice has received consulting fees from Afferent, Merck Sharp & Dohme, Boehringer Ingelheim, Pfizer, and Proctor & Gamble; lecture fees from Boehringer Ingelheim and AstraZeneca; and grant support from Proctor & Gamble. Conflict of interest: M.M. Kitt is a former employee of Afferent Pharmaceuticals and Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and may own stock in the company. Conflict of interest: A.P. Ford is a former employee of Afferent Pharmaceuticals and Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and may own stock in the company. Conflict of interest: A.M. Tershakovec is a former employee of Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA, and may own stock in the company. Conflict of interest: W-C. Wu was an employee of Merck Sharp & Dohme, Corp., during the conduct of the study. Conflict of interest: K. Brindle has nothing to disclose. Conflict of interest: R. Thompson has nothing to disclose. Conflict of interest: S. Thackray-Nocera has nothing to disclose. Conflict of interest: C. Wright has nothing to disclose.