A therapeutic HPV vaccine shrank cervical tumors in mice

An experimental nasal vaccine could one day serve as a treatment for cervical cancer.

In mice, the vaccine unleashed cancer-fighting immune cells in the cervix and ultimately shrank tumors, researchers report November 12 in Science Translational Medicine.

The vaccine targets a cancer protein made by the human papillomavirus, or HPV, and takes a therapeutic approach rather than a preventative one, says Rika Nakahashi-Ouchida, an immunologist at Chiba University in Japan. Treatments like this are urgently needed for people who have already been infected with HPV and now have precancerous lesions growing in their cervix, she says. “We believe these vaccines could expand treatment options for patients.” 

Globally, some 660,000 new cases of cervical cancer are diagnosed each year, with most caused by HPV. Current HPV vaccines like Gardasil-9 are preventative, blocking the virus from infecting the body and stamping out new cases of cervical cancer. A large 2024 study in Scotland, for instance, reported zero cases of cervical cancer among women vaccinated at age 12 or 13 since the country began its vaccination program in 2008.

But preventative vaccines can’t quash existing infections. Infected people who develop cancer must rely on treatments such as surgery, radiation and chemotherapy.

Therapeutic vaccines, which direct the immune system to attack cancer, offer a potential new treatment. While many groups are developing such vaccines for cervical cancer — most as injectable shots — none are available for use. Nakahashi-Ouchida’s team tried a different approach: a nanogel vaccine squirted into the nose.

The team’s gel carries a protein from a cancer-causing HPV strain; researchers modified the protein to be harmless. In mice with cervical tumors, vaccination prompted an immune response to migrate from mucosal tissue in the nose to tumor tissue in the cervix, the team found. Those tumors then started to shrink.

“I was very excited to see that,” Nakahashi-Ouchida says. She hadn’t been sure that nasal vaccination could spark a response in tissue as distant as the cervix. In other experiments in macaques, the vaccine also spurred cancer protein-targeting immune cells to beeline to cervical tissue.

Nakahashi-Ouchida says there’s much to do before such a vaccine is ready for clinical use. She’d like the vaccine to include cancer proteins from other HPV strains, for one. With such tweaks and further testing, she estimates a nasal vaccine for cervical cancer could be available in about five years.