Long-Term Immunogenicity, Effectiveness Observed With HPV Vaccine Gardasil 9

Gardasil^® 9 (human papillomavirus [HPV] 9-valent vaccine, recombinant) was associated with sustained HPV-antibody responses through 10 years among boys and girls who received a 3-dose regimen at 9 to 15 years of age.

Gardasil 9 is a vaccine indicated in females 9 through 45 years of age for the prevention of cervical, vulvar, vaginal, anal, oropharyngeal and other head and neck cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58; cervical, vulvar, vaginal, and anal precancerous or dysplastic lesions caused by HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58; and genital warts caused by HPV types 6 and 11.

It is also approved for use in males 9 through 45 years of age for the prevention of anal, oropharyngeal and other head and neck cancers caused by HPV types 16, 18, 31, 33, 45, 52, and 58; anal precancerous or dysplastic lesions caused by HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58; and genital warts caused by HPV types 6 and 11.

The long-term follow-up study (ClinicalTrials.gov Identifier: NCT00943722) assessed the immunogenicity and effectiveness of the vaccine after the third dose in 301 boys and 971 girls. Antibody assessments showed that geometric mean titers peaked at month 7, dropped between months 7 and 12, and then gradually decreased through month 126. Findings showed that a majority of participants remained seropositive at month 126 (81.3-97.7% based on competitive Luminex^® immunoassay; 94.9-100% based on immunoglobulin G Luminex immunoassay).

Starting at age 16, genital swabs were collected and external genital exams were conducted (every 6 months) to assess for effectiveness. Results showed that among both boys and girls, there were no cases of vaccine-targeted HPV type high-grade intraepithelial neoplasia or condyloma. Compared with similar HPV-vaccinated cohorts from previous studies, the incidence rates of HPV6/11/16/18/31/33/45/52/58-related 6-month persistent infection and disease were observed to be low and within expected ranges (girls: persistent infection: 52.4 per 10,000 person-years; disease: 2.2 per 10;000 person-years; boys: persistent infection: 54.6 per 10,000 person-years; disease: 0 per 10,000 person-years).

“These data highlight the importance of Gardasil 9 in prevention of certain HPV-related cancers and diseases later in life,” said Dr Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “HPV-related cancers and diseases are a significant public health issue. These strong study results serve as a reminder that we need to do everything we can to expand and recover vaccination rates globally to help protect all eligible people from certain HPV-related cancers.”