Merck has posted results from its Phase III efficacy study of 9-valent human papilloma virus (HPV) vaccine (V503). The study showed that V503 prevented approximately 97% of cervical, vaginal and vulvar pre-cancers caused by HPV types 31, 33, 45, 52, and 58. V503 also generated immune responses to HPV types 6, 11, 16, and 18 that were non-inferior to those generated by Gardasil. V503 includes five more HPV types (31, 33, 45, 52, 58) in addition to the four original HPV types (6, 11, 16, 18) in G...