[author: Pam Koenig]

Photo by National Cancer Institute on Unsplash

After a decade or more of research suggesting that the HPV vaccine could be effective in protecting against certain types of head and neck cancer, the FDA has finally given approval for this application of Gardasil 9, the latest version of the vaccine.

Recommendations for Use

In the FDA expanded application, Gardasil 9 is now indicated in females 9 through 45 years of age for the prevention of oropharyngeal and other head and neck cancers, in addition to cervical, vulvar, vaginal, and anal cancers caused by HPV, as well as cervical, vulvar, vaginal, and anal precancerous or dysplastic lesions and genital warts caused by HPV.

For males, the vaccine is now indicated for ages 9 through 45 years for the prevention of oropharyngeal and other head and neck cancers, as well as anal cancers caused by HPV and anal precancerous or dysplastic lesions and genital warts caused by HPV.

Oropharyngeal cancer of the head and neck (sometimes referred to simply as “throat cancer”) is the most common malignancy caused by HPV, and the majority of those cases occur in males. According to the Centers for Disease Control and Prevention (CDC), HPV causes 34,800 cases of cancer each year; of these cancers, 13,500 cases are oropharyngeal, whereas 10,900 cases are cervical. (CDC, 2019)

Evidence Shows Link Between HPV and Oropharyngeal Cancer

Gardasil was first approved in 2006 for females ages 9–26 based on clinical trials showing that the vaccine, by preventing HPV infection, could inhibit the development of precancerous cervical lesions. This type of lesion is not apparent in head and neck cancer, so proving effectiveness of the vaccine for this type of cancer was more challenging. Numerous clinical studies conducted by scientists, such as Maura Gillison, M.D., PhD., a leader in the field of HPV research and professor at M.D. Anderson Cancer Center, found the vaccine effective for oropharyngeal cancer and her research along with the weight of the epidemiological evidence collected in the scientific community as a whole prompted FDA to grant an accelerated approval for Gardasil for the prevention of head and neck cancer.

In 1999, Dr. Gillison was one of the first scientists to link oropharyngeal cancer to HPV. Over time, she and other researchers noted that the rate of oropharyngeal cancers was rising, apparently as a result of HPV infection. The cancers were occurring primarily in middle-aged men and had an easier treatment course and better prognosis than the usual oropharyngeal cancers.

Dr. Gillison and others worked for years to have Gardasil approved for men and women to prevent cancers of the throat. In a 2017 epidemiological study, she and colleagues found that the HPV vaccine given to prevent anogenital cancers was associated with a 17% reduction in carcinogenic HPV prevalence in the oropharynx among young U.S. adults. (Chaturvedi et al., 2017)

HPV Not Just a Problem for Women

According to Dr. Gillison, the public perception is that HPV is only a problem for women in relation to cervical cancer, while in reality, the burden of HPV positive oropharyngeal cancer in U.S. men now exceeds the burden of cervical cancer in women. (STAT News, 2019)

· HPV-associated cancers are considered sexually transmitted diseases

· Diagnosed in areas of the body where HPV is often found

o Cervix, vagina, vulva, penis, anus, rectum, oropharynx (including base of tongue and tonsils)

· The virus gains entrance to basal cells through micro-abrasions in the epithelium

· HPV infection causes common and anogenital warts, as well as other non-dermatological diseases

· Although usually a transient infection, persistent HPV infection is associated with the development of cancer

· Over 200 HPV types have been identified; eight types are clear carcinogens, primarily HPVs 16 and 18

· HPV 16 is present in ~90% of HPV-positive tumors of the oropharynx (IARC, 2012; Brianti et al., 2017)

In February 2020, Merck, the pharmaceutical company that manufactures Gardasil, began a clinical trial of 6,000 men to test whether patients who receive Gardasil are less likely to develop HPV oropharyngeal infections. The study is ongoing and the results will be provided to the FDA for review.

Links to STAT news articles:

https://www.statnews.com/2020/06/12/fda-approves-gardasil-9-the-hpv-vaccine-to-prevent-head-and-neck-cancer/

https://www.statnews.com/2019/09/11/new-evidence-shows-why-the-hpv-vaccine-is-as-important-for-boys-as-girls/

Links to other articles:

Brianti P, De Flammineis E, Mercuri SR. Review of HPV-related diseases and cancers. New Microbiol. 2017;40(2):80–85.

http://www.newmicrobiologica.org/PUB/allegati_pdf/2017/2/80.pdf

Carbone A, De Paoli P. Cancers related to viral agents that have a direct role in carcinogenesis: pathological and diagnostic techniques. J Clin Pathol. 2012;65(8):680–686

https://pubmed.ncbi.nlm.nih.gov/22496514/

Centers for Disease Control and Prevention. How many cancers are linked to HPV each year?

https://www.cdc.gov/cancer/hpv/statistics/cases.htm

Last updated August 2, 2019.

Chaturvedi AK, Graubard BI, Broutian T, et al. Effect of Prophylactic Human Papillomavirus (HPV) Vaccination on Oral HPV Infections Among Young Adults in the United States. J Clin Oncol. 2018;36(3):262–267.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5773841/pdf/JCO.2017.75.0141.pdf

International Agency for Research on Cancer. Biological agents: A review of human carcinogens. Vol. 100B. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, Lyon, France; 2012.

https://publications.iarc.fr/119

Merck announcement of Gardasil FDA approval, June 2020:

https://www.businesswire.com/news/home/20200612005599/en/FDA-Approves-Merck%E2%80%99s-GARDASIL-9-Prevention-HPV-Related

Merck clinical trial (Feb. 2020)

https://clinicaltrials.gov/ct2/show/NCT04199689

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