An experimental vaccine for kidney cancer is off to a promising start. In data from a Phase I trial released this week, the vaccine candidate appeared to be safe and produced a clear immune response in all nine patients at high risk for recurrences of their cancer.
Scientists at the Dana-Farber Cancer Institute and elsewhere developed the vaccine, which is designed to prevent advanced cases of kidney cancer from returning. Since the trial patients received the vaccine roughly three years ago, they have stayed cancer-free. The early results suggest that these vaccines may someday be able to tackle a wider variety of cancers than expected, the researchers say.
Vaccines are generally designed to train a person’s immune system against future threats like the flu or measles. There are some vaccines, like the HPV jab, that are highly effective at preventing cancer-causing infections. But cancer vaccines are more often therapeutic, helping treat someone’s ongoing cancer or trying to prevent reoccurrences.
Though there are some existing cancer vaccines, these have for the most part only provided modest results. But scientists in the field are working on newer approaches to boosting a person’s immunity from cancer, and we can now be optimistic about much more effective cancer vaccines in the near future. One such approach helps our bodies spot the distinct proteins generated by cancer cells as they mutate, known as neoantigens.
“Neoantigen vaccines are personalized cancer treatments that train the immune system to recognize and attack cancer cells,” senior study researcher Toni Choueiri, a medical oncologist at Dana-Farber, told Gizmodo in an email. “They work by introducing a patient’s unique tumor proteins into the body, which the immune system identifies as foreign and attacks them.”
Choueiri’s team includes researchers from the Broad Institute of MIT and Harvard University. The team’s vaccine targets advanced kidney cancers that have begun to spread elsewhere. The clinical trial involved nine patients with stage III or IV clear cell renal cell carcinoma, who all received the standard treatment of surgery to remove their tumors; some patients were also given a drug that boosts the immune system’s response to cancer, called pembrolizumab.
The researchers personalized the vaccines given to their patients. They isolated neoantigens within each person’s individual cancers that seemed to have the best chance of inducing immunity, manufactured more of them, and then included them in the vaccine. So far, the results are highly encouraging.
“We found neoantigen-targeting vaccines in [kidney cancer] are highly immunogenic, capable of targeting key driver mutations (such as VHL) in kidney cancer and induce anti-tumor immunity,” said Choueiri, who is also the director of the Lank Center for Genitourinary Oncology at Dana-Farber. “We also observed a rapid, substantial, and durable expansion of new T cell clones related specifically to the vaccine.”
The findings, published Tuesday in Nature, are important for another key reason. The team’s work originally began with developing a neoantigen vaccine for melanoma, a type of skin cancer known to have a high mutation burden. Kidney cancer, on the other hand, tends to have a relatively low mutation burden, which raised the possibility that the same approach wouldn’t work for these cases. But the results indicate that even these cancers can now be a viable target for neoantigen vaccines.
Phase I trials primarily test an experimental treatment’s safety and tolerance, so it will take more research with larger groups of people to truly know whether these vaccines can be the next big thing in fighting off kidney cancer. But the fact that all nine patients have remained cancer-free after a median length of 34 months (the study’s cut-off date) is welcome news. And the research team is already working on the next phase of its vital research.
“There is now an ongoing multicenter international randomized study that uses a similar neoantigen-targeting personalized cancer vaccine that will be administered in combination with the immunotherapy pembrolizumab,” Choueiri said. “At this time, the study is accruing patients who underwent surgery for their kidney cancer, but remain at high-risk of cancer recurrence.”