Author: Laurie Barclay, MD; Charles P. Vega, MD

Quadrivalent human papillomavirus (HPV) vaccine may prevent infection with HPV types 6, 11, 16, and 18 and the development of related external genital lesions in young men 16 to 26 years old, according to the results of a randomized, placebo-controlled, double-blind trial reported in the February 3 issue of the New England Journal of Medicine.

“Infection with …HPV and diseases caused by HPV are common in boys and men,” write Anna R. Giuliano, PhD, from the Risk Assessment, Detection, and Intervention Program, H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida, and colleagues. “We report on the safety of a quadrivalent vaccine (active against HPV types 6, 11, 16, and 18) and on its efficacy in preventing the development of external genital lesions and anogenital HPV infection in boys and men.”

The study sample consisted of 4065 healthy boys and men, aged 16 to 26 years, enrolled from 18 countries. The primary efficacy goal was to demonstrate that use of the quadrivalent HPV vaccine was associated with a lower incidence of external genital lesions related to HPV-6, 11, 16, or 18. The investigators used a per-protocol population, in which participants received all 3 vaccinations and had tested negative for relevant HPV types at enrollment, and an intent-to-treat population, in which participants received vaccine or placebo, regardless of baseline HPV status.

In the intent-to-treat population, there were 36 external genital lesions in the vaccine group and 89 in the placebo group, yielding an observed overall efficacy of 60.2% (95% confidence interval [CI], 40.8 – 73.8). Vaccine efficacy for lesions related to HPV types 6, 11, 16, or 18 was 65.5% (95% CI, 45.8 – 78.6). In the per-protocol population, the observed efficacy was 83.8% (95% CI, 61.2 – 94.4); for lesions related to HPV types 6, 11, 16, or 18, the efficacy was 90.4% (95% CI, 69.2 – 98.1).

Observed efficacy regarding persistent infection with HPV-6, 11, 16, or 18 was 47.8% (95% CI, 36.0 – 57.6) in the intent-to-treat population and 85.6% (97.5% CI, 73.4 – 92.9) in the per-protocol population. Efficacy regarding detection of related DNA at any time was 27.1% (95% CI, 16.6 – 36.3) and 44.7% (95% CI, 31.5 – 55.6), respectively.

Significantly more participants receiving quadrivalent HPV vaccine had injection-site pain vs those receiving placebo (57% vs 51%; P < .001).

“Quadrivalent HPV vaccine prevents infection with HPV-6, 11, 16, and 18 and the development of related external genital lesions in males 16 to 26 years of age,” the study authors write.

Limitations of this study include narrow age range of the participants and relatively short follow-up period. In addition, participants had no more than 5 lifetime sexual partners, which may have resulted in overrepresentation of participants with a low likelihood of HPV exposure at baseline and a low likelihood of subsequent exposure vs the general population.

In an accompanying perspective, Jane J. Kim, PhD, From the Department of Health Policy and Management at Harvard School of Public Health in Boston, Massachusetts, notes “the extraordinary potential for HPV vaccination to improve health in both women and men.”

“And although enthusiasm for universal vaccination may initially be tempered by uncertainties about the vaccine’s safety, efficacy, and duration of protection (as well as its uptake, acceptability, and cost), many of these factors could very well change in the future,” Dr. Kim writes. “For example, the cost-effectiveness profile of routine vaccination of young men will improve if the evidence of efficacy continues to mount, the vaccine price declines, or coverage among girls and women remains low. To maximize the benefits to the population’s health from health services and interventions, we have a responsibility to use resources as efficiently as possible.”

Merck, the National Center for Research Resources, and the National Institutes of Health supported this study. Merck employs 7 of the study authors and has disclosed various financial relationships with 5 other study authors. Some of the other study authors have disclosed various other financial relationships with GlaxoSmithKline, Qiagen, and/or AstraZeneca. Dr. Kim has disclosed no relevant financial relationships. Disclosure forms provided by the authors and by Dr. Kim are available with the full text of the journal article at the New England Journal of Medicine Web site .

Source: N Engl J Med. 2011;364:401-411. Abstract

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