On December 10, 2014, the Food and Drug Administration (FDA) approved Gardasil 9 (formerly V503; Merck Sharp and Dohme Corp.), a 9-valent prophylactic human papillomavirus (HPV) vaccine that was developed to succeed Gardasil, Merck’s 4-valent prophylactic HPV vaccine marketed in the U.S. since 2006.
Gardasil 9 targets the same 4 HPV types as original Gardasil (types 6, 11, 16, and 18) plus 5 more: HPV types 31, 33, 45, 52, and 58. This additional set of HPV types is believed to be responsible for approximately 20% of cervical cancers. HPV 16 and HPV 18 are responsible for approximately 70% of cervical cancer cases worldwide. Gardasil 9, therefore, potentially prevents approximately 90% of cervical, vulvar, vaginal, and anal cancers. Gardasil’s only competitor in the U.S. market to date is the less popular bivalent HPV vaccine, Cervarix (GlaxoSmithKline).
Gardasil 9 is approved for the prevention of cervical, vulvar, vaginal, and anal cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58 and for prevention of genital warts caused by HPV types 6 or 11. The vaccine is indicated for use in females age 9 through 26 and males age 9 through 15. Gardasil’s only competitor in the U.S. market to date is the less popular bivalent HPV vaccine, Cervarix (GlaxoSmithKline).
There are more than 150 known HPV viruses; more than 40 types can be transmitted via sexual contact. Some of these sexually transmitted HPV types can cause genital warts; other types can cause cancer. Infection with HPV is the major cause of cervical cancer and most anal cancers. HPV vaccines work by triggering an immune response to the targeted HPV types, thereby preventing persistent HPV infection after exposure. Gardasil 9 does not contain live HPV.
The FDA approval was based on safety data from 6 clinical studies that included 13,234 individuals who received at least one dose of Gardasil 9; the most commonly reported adverse reactions were injection site pain, swelling, redness, and headache. Efficacy was evaluated in an active comparator trial of more than 14,000 females ranging in age from 16 to 26 years who were randomized to receive either Gardasil 9 (n=7099) or quadrivalent Gardasil (n=7105). Gardasil 9 demonstrated effectiveness comparable to quadrivalent Gardasil against HPV types 6, 11, 16, and 18 and demonstrated 97% effectiveness in generating immune response against 5 additional HPV types (31, 33, 45, 52, and 58).
There is no evidence that Gardasil 9 provides protection against disease due to HPV exposure that occurred prior to vaccination. Women should continue to have recommended cervical cancer screening after vaccination with Gardasil 9. Gardasil 9 is administered via intramuscular injection; vaccination requires 3 injections. The initial injection is followed by a second injection 2 months later, and a third injection at 6 months.