Merck & Co. Inc.'s human papillomavirus, or HPV, vaccine Gardasil 9 received the U.S. Food and Drug Administration's expanded approval to treat women and men aged 27 through 45 years.

Gardasil 9 — which prevents certain cancers and diseases caused by the nine HPV types — was previously approved to treat patients aged 9 through 26 years.

"The Centers for Disease Control and Prevention has stated that HPV vaccination prior to becoming infected with the HPV types covered by the vaccine has the potential to prevent more than 90% of these cancers, or 31,200 cases every year, from ever developing," said Peter Marks, director of the FDA's Center for Biologics Evaluation and Research.

Gardasil 9 is a new HPV vaccine, not to be confused with Gardasil — an earlier vaccine approved in 2006 to protect against certain cancers caused by HPV — that it no longer available in the U.S. The FDA approved Gardasil 9 in 2014, covering the same four HPV types as Gardasil, as well as an additional five HPV types.

The U.S. regulator's approval of Gardasil 9 was granted to Merck unit Merck Sharp & Dohme Corp.

The approval in women is based on a study of Gardasil in about 3,200 women aged 27 through 45 years, which showed that Gardasil was 88% effective in preventing persistent infection, genital warts, vulvar and vaginal precancerous lesions, cervical precancerous lesions and cervical cancer related to HPV types covered by the vaccine. The approval also takes into account new data on long-term follow-up from this study.

Gardasil 9's effectiveness in men is inferred from results of the study of Gardasil in women, along with results showing Gardasil's effectiveness in men aged 16 through 26 years and immune response data from a clinical trial in which 150 men, 27 through 45 years of age, received a three-dose regimen of Gardasil over six months.

According to the FDA, Gardasil's effectiveness is relevant to Gardasil 9 since the vaccines are manufactured similarly and cover four of the same HPV types.

The FDA granted approval to Merck's application for Gardasil 9 under a priority review, which expedites the review of medical products for a serious or life-threatening condition.

About 14 million Americans get infected by HPV annually, while about 12,000 women are diagnosed with and about 4,000 women die from cervical cancer caused by certain HPV viruses, the FDA stated, citing CDC data.