HPV Vaccination Update: An Important Hurdle

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Summary and Comment

HPV Vaccination Update: An Important Hurdle

The HPV vaccine was highly effective against anogenital and cervical lesions in women with no previous vaccine-specific HPV exposure.

The quadrivalent human papillomavirus (HPV) vaccine — which targets HPV types 6, 11, 16, and 18 — gained FDA approval in June 2006 based on initial results of two worldwide, industry-sponsored, blinded, placebo-controlled phase III trials. Both trials are ongoing, and investigators now report updated findings about this three-dose vaccine’s efficacy in preventing genital warts and cervical lesions.

The first trial included more than 5000 women (age range, 16–24). After a mean follow-up of 3 years, the vaccine was demonstrated to be 100% effective in preventing vaccine-type anogenital warts, cervical intraepithelial neoplasia (CIN) grades 1–3, and cervical adenocarcinoma in situ among recipients with no evidence of prior infection. Results of an intention-to-treat analysis (which also included women with prior infection history) showed that the vaccine reduced the incidence of all cervical lesions, regardless of HPV type, by 20%.

In the second trial, more than 12,000 women (age range, 15–26) were followed for the incidence of high-grade cervical lesions during a mean of 3 years. Vaccine efficacy was 95% to 98% for the prevention of grade 2 or 3 CIN or adenocarcinoma in situ associated with vaccine-specific HPV in women with no evidence of previous infection. In the intention-to-treat population, vaccine efficacy was 44%. For both trials, side effects were largely limited to injection-site reactions.

Comment: These trial results provide an excellent opportunity to evaluate the benefits and risks of widespread immunization against the HPV types that cause most anogenital warts and about 70% of cervical cancers. Although this first HPV vaccine clearly will not prevent all lesions, its efficacy in women without prior infection is remarkable; as an editorialist notes, delaying vaccination could mean a missed opportunity for protection. Still, the long-term efficacy of the vaccine remains to be determined — and cervical-cancer screening will continue to be important even in women who have been immunized.

— Sandra Ann Carson, MD

Published in Journal Watch Women's Health May 17, 2007

Citation(s):

Garland SM et al. Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases. N Engl J Med 2007 May 10; 356:1928-43.

Original article (Subscription may be required)
Medline abstract (Free)

The FUTURE II Study Group. Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions. N Engl J Med 2007 May 10; 356:1915-27.