‘Personalized’ Cancer Vaccines Head to Phase III Trial

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April 17, 2023 – Researchers this past weekend unveiled clinical trial results for a “major breakthrough” that would personalize cancer treatment.

In an early trial, personalized cancer vaccines reduced the risk of recurrence or death among people with late-stage melanoma by 44%. Melanoma is a deadly skin cancer. 

The findings were presented Sunday at the American Association for Cancer Research conference in Orlando, FL. 

The treatment approach uses mRNA vaccine technology that became well-known for its use in COVID-19 vaccines. The personalized cancer shots are created using information from an individual person’s tumor. The vaccines for people involved in the melanoma study were customized in 34 ways that were specific to a person’s tumor. 

Having later-stage cancer is important for developing the personalized vaccines because smaller tumors from early-stage cancer may not have enough tissue for scientists to extract the needed information, the researchers said. 

The trial included 157 people with stage III or stage IV melanoma who had surgery to remove melanoma from lymph nodes or other organs. People in the study were randomly assigned to one of two groups. One group received a current standard treatment called Keytruda. The second group received the standard Keytruda treatment plus the new personalized vaccine. For both groups, people took Keytruda 18 times, with each dose spaced 3 weeks apart. The vaccine group received the vaccine nine times, also spaced 3 weeks apart. 

Among people in the vaccine group, 78.6% were alive and had not had a cancer recurrence 18 months later. In the Keytruda-only group, 62.2% were alive and had not had a recurrence. The metric is called “recurrence-free survival” among cancer researchers.

The short follow-up period and small number of people in the study were considered limits on fully understanding how well the treatment works. Also, researchers said they were hampered by a cancer vaccine shortage during the pandemic. A larger phase III  trial will begin soon, they said. The study was funded by Moderna Inc. and Merck.

The new personalized vaccine approach isn’t just limited to skin cancer, one of the researchers said. 

“The relevance of this study is the impact it could have not just for melanoma patients but for other cancers as well,” researcher and Harvard Medical School associate professor Ryan Sullivan, MD, said in a statement. “From a general cancer therapeutic standpoint, this is a potential major breakthrough.”

The FDA was already aware of the new treatment’s potential and designated it as a “breakthrough therapy” in February, which accelerates government review once the companies submit data for consideration.