An expanding pipeline of vaccines is giving patients new hope against some of the deadliest cancers, by training the body's immune system to attack malignancies.

Why it matters: This personalized approach could make conditions like melanoma and bladder, kidney, pancreatic and breast cancers treatable, and even potentially preventable, via infusion.

• But it still can take months to produce a personalized vaccine, giving the cancer more time to spread.

Driving the news: Moderna reported last week that it launched three clinical trials of an experimental mRNA vaccine therapy in patients with bladder cancer, kidney cancer and a form of skin cancer called cutaneous squamous cell carcinoma.

• The company has partnered with Merck on a late-stage trial of the vaccine technology against melanoma when administered in combination with Merck's immunotherapy Keytruda.
• Meanwhile, German vaccine maker BioNTech has mRNA vaccines against melanoma and head and neck cancers in phase 2 trials.
• University of Florida researchers said last week they used mRNA technology to attack glioblastoma in a small early-stage clinical trial, while researchers at the University of Cincinnati are testing a therapeutic vaccine against pancreatic cancer.

The big picture: There already are vaccines on the market that target human papillomavirus, or HPV, and hepatitis B, which can lead to abnormal changes in cells that develop into cancer.

• But the emerging wave of cancer vaccines are being designed to prime the immune system to seek out and destroy solid tumors not easily cured with surgery, without the side effects that often accompany chemotherapy.
• They build off the success of COVID-19 vaccines, which boosted hopes for mRNA-based therapeutics for a wide array of diseases.

What they're saying: "The immune system needs an address of where to go," Kyle Holen, head of development, therapeutics and oncology at Moderna, told Axios.

• Using genetic sequencing to identify tumor-specific mutations, they create a personalized defense that "basically trains our immune system to know what to fight," he said.

Between the lines: Broad-based treatments have the advantage of getting patients to treatment quicker than personalized vaccines, said Mai-Britt Zocca, CEO of Denmark-based IO Biotech, which has a melanoma vaccine in phase 3 trial.

• Their vaccine targets tumor cells as well as immune-suppressive cells that are universally found in melanoma. "Therefore we don't need to do any personalized manufacturing," Zocca said.

What to watch: The field is ultimately working toward the holy grail — preventing cancer altogether. In theory, the therapeutic vaccines could be used to prevent cancer from even starting, the companies said.

• Some researchers, like San Jose, California-based Anixa Biosciences, are trying to create those preventative vaccines first.
• Based on methods developed at the Cleveland Clinic, Anixa is aiming to prevent triple-negative breast cancer using a vaccine that targets a protein produced in the body when a woman is lactating or when the breast cancer develops. They recently reported a positive early-stage trial.
• "If this approach works for breast cancer, it could work for many other cancers," said Amit Kumar, Anixa CEO.

Editor's note: This article was corrected to note that IO Biotech is headquartered in Denmark (not Rockville, Maryland, where it has a U.S. office). It also clarifies that Merck, maker of Keytruda, is a partner in the development of a cancer vaccine with Moderna.