Bridging Studies for Older Populations
Although HPV VLP vaccines are meant to target young people before exposure, they have been shown to offer protection against one oncogenic HPV type (either HPV-16 or HPV-18) in female patients who are infected with the other oncogenic HPV type.[60,61] Thus, vaccine manufacturers and regulatory agencies in other countries sought to expand the vaccine indication to females aged 26 years and older. With age simply representing likelihood of previous sexual intercourse and HPV exposure, women of advanced age with few or no sexual partners may also gain protection from vaccination; thus, it is logical not to deny vaccines to these populations.
A bridging study was conducted to evaluate vaccine-induced immune responses in two age cohorts outside those used in the clinical efficacy trials. Women aged 26–45 years and those aged 46–55 years were compared with girls and women aged 15–25 years with respect to seroconversion rates and antibody levels after vaccination with the bivalent vaccine. In all age groups, women who were seronegative initially achieved seroconversion for both HPV-16 and HPV-18 1 month after the third dose of vaccine. A decrease in geometric mean antibody titers was observed with increasing age, again forcing the issue of waning protection and need for even more frequent boosters in these age groups.
Pharmacotherapy. 2011;31(3):280-297. © 2011 Pharmacotherapy Publications
Cite this: Clinical Perspectives on the Role of the Human Papillomavirus Vaccine in the Prevention of Cancer - Medscape - Mar 01, 2011.