Breast Cancer Vaccine Trial: What You Need to Know with Dr. Thomas Budd

Podcast Transcript

Intro:
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Molly Shrodes:
Hi, and thanks for joining us for this episode of the Health Essentials Podcast. My name is Molly Shrodes, and I'll be your host. Breast cancer is one of the most common types of cancer. Experts have looked for ways to improve treatment options for people with breast cancer for years. But what about preventing the disease? Oncologist Thomas Budd is the principal investigator for the trial that is looking at ways to develop a preventative vaccine for breast cancer. Thank you for joining us, Dr. Budd.

Dr. Thomas Budd:
Hi Molly. Nice to be here.

Molly Shrodes:
So starting off, can you tell us a little bit about your role in this trial?

Dr. Thomas Budd:
Well, I am the principal investigator of the clinical trial. It's based on preclinical work, meaning laboratory studies done by my colleague, Dr. Vince Tuohy. Now we would like to launch this into a human trial and that's my role, is to be a principal investigator in that clinical trial that will advance this research into human beings in the first phase.

Molly Shrodes:
Wonderful. So can you tell us a little bit about the trial itself and what's being tested?

Dr. Thomas Budd:
The trial is the first study along a long road that we hope will lead to a vaccine that can prevent at least some breast cancer. The trial is a vaccine trial against a protein. That protein is called Alpha-lactalbumin. In a normal woman, it is expressed only when she's making milk. It's a milk protein, and it's expressed normally only in the breast when it's making milk. Other than that, that protein is not being produced by any other organ in the body at any other time. Now tumors, because they don't follow the rules, can make this protein when they're not supposed to and it turns out it's particularly triple negative breast cancer, for some reason, that tends to make too much of this protein. And so, 70, 80%, at least some studies, of triple negative breast cancer will express this protein. So we think it could be a target for a vaccine so long as we can be sure that the woman who receives the target would not go on to become pregnant and make milk.

Molly Shrodes:
Gotcha. So how many participants are going to be involved in this?

Dr. Thomas Budd:
Well, the simple answer is 18 to 24. The more complicated answer is, it depends. It's what's called a phase I trial, so we start out at a low dose. We treat one to three patients, make sure they do okay. If those patients have no problems, we go to the next dose. If they do have a problem, we may enter more patients at that dose level just to make sure it's safe, and then we go from there to subsequently higher dose levels. So it depends a little bit on whether we see any side effects and what they are, but once we've figured out how much we can give, we'll be wanting to look at the effects on the immune system. That will help us know whether the vaccine is doing what we want it to and to do that, then we will expand each dose level so long as we see some immune effects to six patients.

So we actually may, after we've treated six patients at the highest dose, we actually may go lower if we have a hint of the immune response and see if we really have to go to the highest dose. And we also have a provision. We pick three doses, but we may want to look at a dose in between two doses, and we have a provision to allow that if necessary. So it's a long answer, but the short answer is somewhere 18 to 20.

Molly Shrodes:
Great. So is this primarily women?

Dr. Thomas Budd:
It is open to men as well as women. Realistically, we don't expect many if any men to enter the trial, and this is because breast cancer in men, while it certainly is a problem, is only 1% of all breast cancer. Moreover, we're looking at what's called triple negative breast cancer, which means it's negative for the estrogen receptor, negative for the progesterone receptor, negative for the HER2 molecule, and most male breast cancer is positive for the estrogen receptor. So we're talking about 10% of 1% of all breast cancers. So it's very unlikely that we will enroll a man, but certainly we are open to all human beings who meet the eligibility criteria.

Molly Shrodes:
How are these participants going to be selected?

Dr. Thomas Budd:
Well, they'll be selected according to eligibility. In other words, we have a set of rules. We want to make sure that they've completed all their standard treatment so that we're not shortchanging them in terms of treatment that we already know is beneficial, and they have to have certain other characteristics, be generally healthy. There are certain medications we worry about that might be associated with lactation or milk production as sort of an adverse side effect, and some other criteria in terms of major organ function. We just want to make sure they're generally healthy. So those are the general criteria and we are accumulating a list of potential participants that we will approach.

Molly Shrodes:
Now for these people, how often will they receive doses, and how long will they be monitored?

Dr. Thomas Budd:
In this trial, we will give doses once every two weeks for three times, they'll be monitored at each visit, and then they'll be monitored thereafter for a total of 84 days assuming all side effects have resolved. If there are significant side effects that haven't resolved, of course we'll continue to follow those participants.

Molly Shrodes:
Are people in this trial currently being treated for breast cancer?

Dr. Thomas Budd:
People entered in the current trial will have completed all standard treatment for their cancer, but are at risk to have the cancer come back. So they stand, if this is effective in this setting, would stand to have some benefit. But of course it's experimental. We know it has some potential for side effects. We don't know whether it will have a significant effect on the chance of their cancer coming back. But this is the group that we're studying first and later, we'll move on to patients who have never had breast cancer, but who are at risk to develop it.

Molly Shrodes:
It sounds like we're in an early phase here. What's going on at this point?

Dr. Thomas Budd:
This first trial will be in patients who have a history of breast cancer, specifically this triple negative breast cancer that I mentioned earlier, and have completed all prior treatment. It will be stages two A to three, or patients who received chemotherapy before surgery, had surgery and had some cancer left in the breast. Those patients will also be eligible and can be entered on the trial once they've completed all their standard treatment.

I should point out that this group of patients or participants is not the final group that we hope to be able to treat with this. It's the starting point. These are patients who already have breast cancer, have something potentially to gain from this. And once we've figured out the side effects, what dose we ought to give, then we want to study patients who are at risk to develop breast cancer. And we can identify these to start with, by looking at patients who have a genetic risk to develop triple negative breast cancer.

Molly Shrodes:
Great. Now, I think for many people they don't realize that there's a lot of different types of breast cancers and different stages. Can you talk a little bit about triple negative breast cancer and the different stages?

Dr. Thomas Budd:
Sure. So the stage of disease means how extensive it is in the body. There is a stage zero for something called ductal carcinoma in situ. Then there are stages one, two and three, which are still early stages able to be operated on, but the higher the stage, the higher the risk of it spreading to other organs, and the more likely you need what's called systemic treatment chemotherapy, that sort of thing. Stage four is when it's already metastatic or spread to other organs. Unfortunately breast cancer, when it's stage four, in general, we say that it's incurable although certainly we can treat it and people can lead meaningful lives.

Triple negative breast cancer refers to breast cancer that is negative for three proteins. Estrogen receptor, progesterone receptor, and HER2. And that's important, but it's also important to notice that we're talking about what it's not rather than what it is.

So estrogen receptor positive breast cancer is actually the majority. These are breast cancers that have a protein called estrogen receptor, which basically means they're fed by estrogen and we can use that fact to affect their growth by starving them of estrogen. HER2 positive breast cancer makes too much of this protein called HER2, and that's sort of the Achilles heel for patients' tumors. So we have targeted treatments that target that HER2 abnormality and can kill the cancer cell. Triple negative breast cancer doesn't have any of these targets, so then we're presently stuck with primarily chemotherapy, which is helpful in treating these patients, but is relatively non-targeted. So we have chemotherapy. Now there are some recent efforts to find targets so that we're not defining it by what it's not, and there are some efforts to harness the immune system to treat triple negative breast cancer, and there is just recently an immune stimulant drug, which is approved for treating triple negative breast cancer. So it kind of fits well with our theme of a cancer vaccine to prevent.

Molly Shrodes:
Can you tell me a little bit more about how the vaccine is going to work? A little bit of the science behind it?

Dr. Thomas Budd:
Well, the idea is, as I said earlier, that some breast cancers make too much of this Alpha-lactalbumin protein, and that protein is not made in a normal person except when a woman is lactating. So it could be a so-called immunologic target, where you can stimulate the immune system to attack cells and make too much of that protein, and as long as you're sure that the woman is not going to be lactating or making milk, then the side effects should be few. That's the general idea behind it. We give the protein plus another drug called an immunologic adjuvant that kind of tells the immune system, Hey, take a look at this protein, we think it's something bad, and causes an immune response. The immune response that we're looking at primarily is in a set of cells called T-cells, which attack cancer cells and other cells that are infected say by an organism. We also will be looking at antibodies against this Alpha-lactalbumin. Antibodies I think are familiar to everybody now, unfortunately, with COVID-19.

Molly Shrodes:
How do you know that you're at risk? Is this a genetic test you can take?

Dr. Thomas Budd:
For this particular trial, the first trial that we're doing, this phase one trial, these are patients who have a history of breast cancer, so they know they're at risk. Moving forward, we will want to test this and hopefully find it effective in women, primarily women who are at risk to develop triple negative breast cancer. And to start with, this would be women who have certain genetic abnormalities who put them at very high risk. BRCA1 is the most notable among these. So these are patients who have a very high risk of developing breast cancer, maybe 75, 80% risk over their lifetime. And these are women who sometimes undergo bilateral mastectomy to prevent the cancer, so they get rid of as much breast tissue as they can to prevent the possibility of getting breast cancer. So this is the group of women that we would first think about benefiting from this vaccine. But if it's safe, maybe there are other groups that could be identified in the future. If it's safe and effective.

Molly Shrodes:
Now I'm wondering about the timeline for this trial. I understand that vaccines take a very long time to get out there to the public. How long does it take to develop and test something like this?

Dr. Thomas Budd:
It will take years. So this first phase, this phase one trial, we're just trying to find out, does it have side effects? Are the side effects acceptable? How much should we give? And that can be based on side effects, but also the immunologic response. The end points we're really looking at are side effects and whether we can detect an immune response against this target of interest, this Alpha-lactalbumin. And from these studies, we'll figure out what dose we should give in future trials, and we can go from there.

I kind of see a bifurcated or divided way to develop this. For patients, like the patients we're treating here who have early breast cancer, may have had breast cancer, there may be a role for this, perhaps in combination with some immunologic stimulant, but when we're really interested in prevention, we'll move forward on a separate path. It will really take years, because the number of participants who would be open to these trials is relatively small and it takes years to see whether you're preventing a cancer that may occur over a person's lifetime. So it will take years to develop, but we have to start somewhere and we're really excited to take our first step.

Molly Shrodes:
Now, looking way down the road. Could this vaccine ever be adapted or modified to be a preventative vaccine for other types of cancers? Could this expand beyond breast cancer?

Dr. Thomas Budd:
Well, I think this particular vaccine would be unlikely to be useful in other diseases, but the concept behind it could be applied to other diseases and other cancers specifically. There may be other proteins that are expressed only under certain particular situations that are also expressed in cancer, and this could be exploited. The particular immunologic adjuvant we use could be used with other proteins, so that I think there is a future for this general approach. I should point out that there are vaccines that prevent cancer already, hepatitis B, HPV. These are aimed at virally induced cancers and are quite effective in very important public health measures. That's a first step, but there may be other proteins that are non-viral proteins that we can target with vaccines so long as we can do it safely.

Molly Shrodes:
That's very interesting and hopeful for the future. Now, as we wrap up, I just want to talk a little bit about the future. Looking ahead, what are your hopes for this vaccine and how could it impact people in the long run?

Dr. Thomas Budd:
Well, my hope is it will prove to be safe and effective and that we will be able to prevent triple negative breast cancer, really, so far the worst type of breast cancer in women. Men are unlikely to be vaccinated at this point because their risk is low, so it'd be primarily women. And ultimately, we hope that this can be one more tool that we have to prevent breast cancer, because prevention is much better than trying to treat a disease with the treatments we have available now.

Molly Shrodes:
Thank you so much for joining us today and sharing your insights Dr. Budd.

Dr. Thomas Budd:
Sure. My pleasure. Nice to talk with you.

Molly Shrodes:
To learn more about Cleveland Clinic's comprehensive breast cancer program, visit clevelandclinic.org/breastcancer.

Intro:
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