Timothy J. Wilkin
Results of a phase 3 trial recently published in Clinical Infectious Diseases showed that the quadrivalent HPV vaccine was not effective in preventing new anal infections or improving high-grade squamous intraepithelial lesions in adults aged 27 years or older with HIV.
Because this population often has a history of HPV, as well as a high prevalence of anal and oropharyngeal cancer caused by the virus, Timothy J. Wilkin, MD, MPH, associate professor of medicine in the division of infectious diseases at Weill Cornell Medicine, and colleagues said their findings underscore the importance of vaccinating boys and girls before HPV exposure.
The researchers assessed the efficacy of HPV vaccination in 575 men and women aged 27 years or older in the United States and Brazil who were enrolled in the phase 3 ACTG A5298 trial. Since the nine-valent HPV vaccine (Gardasil-9, Merck) was not approved by the FDA when the study was initiated, participants were randomly assigned in a 1:1 ratio to receive the quadrivalent HPV vaccine (qHPV; Gardasil, Merck) or placebo at baseline, week 8 and week 24. The primary endpoint was the prevention of persistent anal infections or a new anal infection at the final study visit with qHPV vaccine types (6, 11, 16 and 18). Secondary endpoints included the incidence of anal high-grade squamous intraepithelial lesions on biopsy (bHSIL), which precede anal cancer, and oral HPV infections with vaccine types.
“Some reports suggest that patients who have received an HPV vaccine respond better to treatments of anal HSIL and cervical HSIL,” the researchers wrote.
According to the findings, 27 participants who received qHPV and 33 who received placebo had persistent anal HPV infections, yielding a vaccine efficacy of 22% (95.1% CI, –31 to 53). Additional data showed the vaccine was 0% (95% CI, –44 to 31) effective against anal bHSIL and 32% (95.1% CI, –80 to 74) effective in preventing persistent oral HPV infections. However, vaccine efficacy against persistent oral HPV significantly increased to 88% (95.1% CI, 2-98) when researchers excluded from their analysis participants with a single oral infection at the final visit.
Although the researchers had planned to follow participants for 3 years, the Data and Safety Monitoring Board stopped the trial early due to the lack of vaccine efficacy. Wilkin and colleagues concluded that their data do not support HPV vaccination to prevent new anal infections or improve anal HSIL outcomes in patients with HIV aged 27 years or older, but the vaccine could play a role in preventing oral infections.
“I believe it is imperative to conduct a clinical trial to definitively prove efficacy for the prevention of oral HPV and, by extension, HPV-related oropharyngeal cancer,” Wilkin told Infectious Disease News. “I would not recommend widespread HPV vaccination in this group based on currently available data.”– by Stephanie Viguers
Disclosures: Wilkin reports receiving grant funding on behalf of his institution from Bristol Myers-Squibb, Gilead Sciences, GlaxoSmithKline and ViiV Healthcare. He also reports receiving honoraria from GlaxoSmithKline and ViiV Healthcare. Please see the study for all other authors’ relevant financial disclosures.