Leading Breast Cancer Expert Shares Clinical Research on Vaccines

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Andrew Schorr:

And hello.  I'm Andrew Schorr from Patient Power.  Welcome to this program.  We're talking about breast cancer and the whole idea of your immune system and can a vaccine help different subsets of breast cancer patients.  And joining me is an expert researcher in the field, Dr. Sasha Stanton from the University of Washington. Dr. Stanton, thanks for being with us.  

Dr. Stanton:

Absolutely.  Thank you so much for having me.  

Andrew Schorr:

So, first of all, let's make it clear.  When we talk about a vaccine, this is—is it to prevent breast cancer?  Or is it to be a treatment if you have breast cancer? How do we think of it?  

Dr. Stanton:

So we're actually thinking of it in both ways, and I think the vaccine by itself is really going to be much more for prevention, and there are two ways to look at that.  It is both preventing breast cancer if you've never had it and you have a risk for it or preventing breast cancer if you've had it to prevent it from coming back.  

And right now in our current clinical trials we are much more looking at that second question.  So we have a vaccine for patients who have had breast cancer in the past, and we're trying to teach their immune system. Much like you'd teach your immune system to recognize if you've had the flu and destroy it, we want to teach their immune system to recognize if they get a cancer that comes back again and destroy it before it became spread throughout their body.  

Andrew Schorr:

Okay.  

Dr. Stanton:

But in my work in the laboratory I am looking much more into prevention, which would be taking a patient population that had never had cancer and teaching their immune system to prevent them from ever getting it, much like the measles vaccine that you would try to never, ever have measles.  

Andrew Schorr:

Okay.  And that would be just like—I have a loud siren here.  I'm not near a hospital, but—there we go.  So some of us are familiar now with the HPV vaccine, which younger people are now being urged to get as well.  So are we saying that you could see the day where to ward off the risk of breast cancer that we might have a vaccine used that way? 

Dr. Stanton:

Exactly.  That would be, that would be our goal.  It is absolutely still in the laboratory for that.  When you're considering that you have to find parts of the body—so for HPV it's a virus.  It's not something that's our cells, and so we're able to vaccinate against it, and it doesn't react with our normal cells in our body.  

With breast cancer, it's our cells, and so we have to find targets that won't cause problems with our normal functioning of our body, and that is what a lot of my colleagues at the University of Washington and throughout the country and the world have been working on for this to develop a prevention vaccine that would be a pure prevention vaccine.  

Andrew Schorr:

Okay.  So many of our viewers are people who have or had breast cancer, and you're saying, well, one thing would be to prevent a recurrence. So is your thinking that you could be five years out, 10 years out, 20 years out?  Where would this come into play?  

Dr. Stanton:

So very good question. Our current trial that we have running that's we call Walk Back is actually—there is no limit on how far out you are from breast cancer.  You just have to not—you have to have either stage II or III breast cancer.  So the hope would be that you could be as far out as you are as long as we can find the correct immune response for you, to induce for you so that you not have the cancer return.  

Andrew Schorr:

Okay.  And people have different subtypes of breast cancer, so where does that come into play if somebody had the BRCA gene or triple negative or—help us understand because women are beginning to understand not all breast cancer's alike.  

Dr. Stanton:

Absolutely.  And I think that is again what we need to find or really understand and—is what proteins or what targets that we vaccinate against will be represented in different types of breast cancer?  So for our HER2-positive patients we need to include HER2, because we know that that is a driver of that growth of breast cancer.  So if we could have our immune systems see that and therefore destroy the cells that overexpress that protein, that would be important for them.  

In ER-positive breast cancer and in triple-negative breast cancer we have other proteins that are over expressed.  Triple-negative breast cancer has a lot of stem cell-like proteins, and we actually had a vaccine called STEMVAC that we have completed a Phase 1 clinical trial in again looking to target those breast cancer stem cells.  So it is important, and in my work I have been looking across the breast cancer subtypes to try to find targets that will hit multiples of the subtypes.  Because you're absolutely correct that not all breast cancer is the same.  

Similarly, we know that the immune response that's developed against each of the different types of breast cancer is different, and so we--as a second part of my research is also trying to figure out how we can use different immune therapies along with vaccines to ensure that each of the different subtypes can actually respond to a vaccine and have the efficacy of a vaccine.  

Andrew Schorr:

Okay.  I can hear people asking these questions.  I'm going to pass them on to you.  One is, like with the flu vaccine there are people that say, I got my flu shot and I got the flu.  It gave me the flu.  Okay- Well, it would be terrifying if a woman had thought she'd beaten breast cancer but wants to prevent its recurrence and something that you give them in a shot brings the breast cancer on.  

Dr. Stanton:

So I have to say that that is a very good question.  The flu vaccine and the cancer vaccines that we've been given—have been testing, should not give you the flu or give you cancer.  I think that we—with the flu vaccine what happens is you have a form of the flu that isn't covered by the vaccine, and I think you're going to have that same problem in breast cancer, that you'll receive a vaccine that will cover as much of breast cancer as we can, and that cancer will be wily enough to get around whatever we've vaccinated and another type of cancer will come.  

But we've done vaccinations and vaccine studies in breast cancer for decades now in the Cancer Vaccine Institute at the University of Washington and have no data that we are inducing cancer with vaccinating.  I think what is happening is we may not be able to control it with our understanding of the immune system and how we're developing vaccines, but we learn more and more and more every day and with the goal of really getting to the point that we can do that.

Andrew Schorr:

Okay.  So you run clinical trials, and there may be some women watching who want to be part of it.  So what's involved?  Is it just like you went to the pharmacy and you get a shot and you're done, or what—just the logistics of it.  

Andrew Schorr:

So the logistics of our trials right now that we have a vaccine series.  So it is more like the hepatitis vaccine or the HPV vaccine where you come once a month for three months and you get a vaccine for each of those three months. And once you've completed that series we bring you back one month after to check and see how your immune system responded to that vaccine and then six months after that to see if it's prolonged, if you continue to have a response.  

So right now that is what it entails.  I believe as we move this forward and we need to follow people's immune responses, their titers, we're going to have to possibly do boosters where people will come back and have to get a second vaccine a year out, two years out, farther down the line.  But right now that's how our vaccines are typically structured.   

Andrew Schorr:

Okay.  And what phases are these trials in?  

Dr. Stanton:

Most of these are in Phase I trials, so in the safety trials.  They are not yet in the efficacy trials where you're comparing them against people who are getting a placebo.   

Andrew Schorr:

Okay.  And you're at the University of Washington in Seattle.  Are these trials being done elsewhere or just at your place?  

Dr. Stanton:

So the Walk Back trial that I mentioned has two sites, actually.  It's the University of Washington and the University of Wisconsin. We have another vaccine trial that we have in HER2 positive patients that we are doing in collaboration with Moffitt down in Florida and the University of Washington, and some of the trials are just here.  Again, they're earlier trials.  

Andrew Schorr:

Well, that's something to inquire, but let's just, as we wrap up, think of it more broadly.  So immunotherapy, some people have heard about checkpoint inhibitors in lung cancer and some of the different cancers to kind of teach your immune system to fight the cancer it missed earlier.  So is this part of the same concept, to inject something in, to activate your immune system to have this surveillance against the cancer you might otherwise develop?  

Dr. Stanton:

Absolutely. Absolutely.  And we are looking at—so we talked about prevention and we talked about people who have—who have had cancer to prevent it from coming back, but what about the people who have metastatic cancer?  So I'm a breast oncologist.  I have patients who are like, well, that's great, but what about me? And we are looking at combining all of these different immunotherapies, CAR?T cells, which are chimeric antigen receptor T cells.  They are basically your own T cells that we have modified to give back to you to fight a cancer.  Or immune checkpoint inhibitors with vaccines or vaccines with chemotherapy.  

And we're looking at many of these different combinations much more to target women who have disease, still have disease as well as women to prevent recurrence.  

Andrew Schorr:

So, as you said, you're a medical oncologist.  As you do this research and seeing patients as well, should it give us hope?  

Dr. Stanton:

Yes.  I believe that this should give hope.  There are many, many brilliant minds working to try to address issues, and I have to say in breast cancer we also have many, many brilliant advocates who are patients who really help us guide what we're looking at and what questions we're addressing.  

And my advocates call me to task all the time.  Well, why are you asking this and not that?  And it's important, it's critical, it's fantastic, and I really do want patients though to have hope.  Because we are—we're trying our hardest.  There are many sleepless nights where I worry about my patients, and there are also many sleepless nights where I worry about my research, so we are working very hard for this but we still have a long way to go.  

Andrew Schorr:

Well, first of all, Sasha Stanton, we're all in it together, and we want to thank you for your devotion. Godspeed in your research and your colleagues around the world working on this.  And let's see whether vaccines, used alone or in combination can make a difference in prevention or in heading off recurrence.  Thank you for all you do, Dr. Sasha Stanton from the University of Washington.  

Dr. Stanton:

Thank you.  

Andrew Schorr:

Okay.  I'm Andrew Schorr.  Look for a lot more we'll be doing for those of you living with breast cancer, families affected by breast cancer, families worried about breast cancer. And we always welcome you sending us questions and comments.  Send them to comments@patientpower.info.  

Andrew Schorr reminding you knowledge can be the best medicine of all.  

Please remember the opinions expressed on Patient Power are not necessarily the views of our sponsors, contributors, partners or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.