Researchers Are ‘Building Up the Wall of Evidence’ to Support Cancer Vaccines in the Future

Recent announcements from pharmaceutical companies have focused on the cancer vaccines space, and these may indicate a big step forward in making these a reality for patients with cancer, an expert said.

For example, Moderna and Merck announced positive preliminary findings from the KEYNOTE-942 trial assessing a messenger RNA (mRNA) vaccine with Keytruda (pembrolizumab) for patients with stage 3 to 4 melanoma at high risk for recurrence after complete resection. Other announcements have been made regarding vaccines for breast, prostate and colon cancers.

CURE® spoke with Dr. Catherine J. Wu, professor at Harvard Medical School, chief of the division of stem cell transplantation and cellular therapies and Lavine Family Chair of Preventive Cancer Therapies at Dana-Farber Cancer Center in Boston, to learn more about what to make of the recent news on cancer vaccines, how they may be used in patients and things that occurred in the past few years that are making people take note of these stories more than before.

“I think that each of these pieces of information that come out there, brick by brick, (are) building up the wall of evidence to support this,” Wu told CURE®.

What are your thoughts on these recent stories in the news about cancer vaccines?

Some of (the data) are published, and some of them are not published. Some of them are (press) releases, or some of them haven't necessarily been vetted out in publications, where they go through peer review. In general, cancer vaccines are not new. They've been around for a while. They kind of come, they kind of go. I would say that there are three general things that are different than before.

The first general thing is, we are in the genomics age. So 10 years ago, sequencing came along, the Human Genome Project happened, then next-generation sequencing happened. And the sequencing costs keep going down. So the impact of genomic medicine, in terms of where we are, continues to resonate. And what that means is that our ability to unlock the secrets of individual tumors, individual immune systems, continues to happen over time. That's a big change compared to 30 years ago.

Another big change is that we're in the age of human immunology. So sequencing is one aspect, but across the board, in terms of the tools that we have to directly understand human disease has never been before. It's an exciting time. And what that also means is that if there's clinical trials, we can actually follow and try to understand and learn from our patients directly from their samples or biopsies, what was the impact of those therapies.

No. 3 — it’s a big one — (is the) pandemic, COVID-19, COVID-19 vaccines. The first two is the progression of science. And the third thing was this big, disruptive thing that no one ever imagined, or maybe some people knew would happen. But what most of us didn't know that this was going to be what it was. And so suddenly, … it's a massive experiment, millions of people in the world got therapy with a new type of vaccine. And I think … we're emerging out of the pandemic in one way. We're going to live with it. We're not dying like people were in March 2020.

Are these the most positive signals that we've had regarding cancer vaccines?

I think there's been continuous positive signals since five years ago. I think it depends on what kind of signal you're looking for. So there's biologic signals, and there's clinical signals. I think the biologic signals, some of the first studies were (done) … back in 2016, 2017, small studies, but the biology was good.

I think what we're beginning to see now is large clinical studies that are building on those works. And that's what's really exciting. So I hope this will get us on a path toward something that's actually — any patient couldn't go to the clinic and say, dial me up a vaccine and comes out of the pharmacy and there you go.

Should we look forward to cancer vaccines in the future?

Yes, absolutely. … I think that there's concerted efforts, both on the academic side and also on the industry side, to work on this. Academics can do signal finding, they can do small studies. We really rely on our industry partners to really support the large studies that are going to be able to — to have the resources to be able to follow out the patients and look at the impact. But the signals are all in the positive.

If you had to predict, when do you think cancer vaccines will become more of a reality?

I would hope in the next three to five years.

Would patients get the vaccine ones and that’s it or would it be administered on a schedule similar to the flu vaccine?

I think that's still open.You'll recognize that cancer is not one thing. Even COVID-19, which is one thing, is different among people. Some people have mild cases, some people have really long, complicated cases. And that just speaks to heterogeneity.

I think cancers, you have more aggressive cancers, you have less aggressive cancers, you have different paces of disease, different durations that people have had cancer, so I think it depends. For example, if this was for treatment of someone with very severe cancer, one could imagine many doses and combinations together with maybe other therapies too that we have out there, like antibodies and so on and so forth. If it were after surgery and it was really to help prevent relapse, maybe that would be a very short course and in the same way that give a shot here.

Would these vaccines be for all cancer types or are some cancer types better suited for them than others?

In general, cancer vaccines should be cross cutting. It's really trying to focus on the immune system to mount a response against the patient's own tumor cells. So I think the principles are the same across systems, but, of course, it's about the details. Depending on the setting, there's different bells and whistles. If there's a particular targeted therapy that works really well in one disease and it has a synergistic effect with a vaccine, that could be really attractive, for example.

When would a patient receive the vaccine in the timeline of a cancer journey?

In general, vaccines work best in the setting of when there's not a lot of active tumor cells around. So either in the beginning when the immune system is a little bit more intact or maybe in conjunction with surgery, for example, after the surgery. So I think in general, vaccines serve a really great mop-up function. So when there's not a lot of tumor on board and just trying to get the immune system to do the final cleanup.

Transcription edited for clarity and conciseness.

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