Welcome to The Breastcancer.org Podcast, the podcast that brings you the latest information on breast cancer research, treatments, side effects, and survivorship issues through expert interviews, as well as personal stories from people affected by breast cancer. Here's your host, Breastcancer.org Senior Editor, Jamie DePolo.
Jamie DePolo: Hi, I’m Jamie DePolo, senior editor at Breastcancer.org. I’m podcasting live from the 2023 Breast Cancer Symposium. My guests now are Drs. Justin Johnson and Thomas Budd. They are doing research on a breast cancer vaccine. We talked to them back in March and now they’re presenting a poster at the conference that has an update on the research.
Dr. Johnson, tell us what you found.
Dr. Justin Johnson: So, we’ve got some really exciting interim results that we’re presenting right now and it’s an update from the poster that you saw last year, which showed very preliminary immunologic data.
We now have a full set of data on our first 16 subjects in the trial, and so far we’re seeing an immune response to the vaccine in the majority of these subjects. So, we don’t know yet if this is going to confer any clinical benefit yet, you know, and this is a phase I trial. So, we’re not looking for efficacy, but having an immune response to the vaccine is an important first step to having protection against breast cancer.
Jamie DePolo: Of course, and for anybody who didn’t listen to the first podcast, if you could remind us, I know there was a special protein that the vaccine is targeting, if I’m using the correct language, if you could just briefly explain that for us again?
Dr. Justin Johnson: Yeah. That’s exactly right. We’re targeting a protein called alpha-lactalbumin. It’s a harmless and normal protein found in milk, including human milk, and when women are lactating they make alpha-lactalbumin, but that should be the only normal condition under which a woman would produce alpha-lactalbumin.
What we found, is that women that are no longer having children don’t make alpha-lactalbumin, but many breast tumors do, including and especially triple-negative breast cancer, which as you know is very aggressive and has limited treatment options. So, we’re hoping that our vaccine can protect women against this very aggressive type of breast cancer.
Jamie DePolo: And I’m also wondering how did you select the 16 people that are in this phase I trial? What characteristics do they have in common?
Dr. Justin Johnson: Well, Dr. Budd can give you a lot more information on the clinical side of things. I’m on the research side of things…
Jamie DePolo: Got you.
Dr. Justin Johnson: …but I can tell you that we have three cohorts. The one we call phase IA is women who have had triple-negative breast cancer, but are in remission and have completed their treatments and are within three years of having completed the treatments. And we are immunizing them, again, this is not for efficacy…
Jamie DePolo: Right.
Dr. Justin Johnson: …but eventually these women will find out if they’re protected or not. Our phase IB cohort is women that have never had breast cancer, but carry a genetic risk marker and are concerned enough about that, that they have already chosen to go to Cleveland Clinic and have a risk-reducing mastectomy, and so, this gives us an opportunity to immunize healthy women who will be at lower risk for any adverse reactions because let’s say there were to be an unforeseen reaction in the mammary gland, their glands are coming out anyway, and we’ll be able to get a sample of this healthy tissue, which you normally wouldn’t be able to get, after they’ve had the vaccine to see if there are any adverse reactions in the tissue.
And then finally we just also opened up a cohort of patients that are essentially the same as the phase IA cohort, but they are being treated with pembrolizumab, also known as Keytruda, which has become the standard of care since we opened the trial several years ago.
So, it’s very important to know, now that so many patients are getting pembrolizumab, if the vaccine is going to work in that population and if it’s going to be safe in that population. So, again, we’re not looking at efficacy, but we want to see toxicity and we want to see an immune response, and if we get an immune response in these…in any of these cohort’s patients, that’s a very good sign that it could perhaps have clinical benefit.
Jamie DePolo: And for those of us who aren’t scientists, so, you get an immune response, then what are the next steps? Like how long are we thinking before you might have some ideas about efficacy?
Dr. Justin Johnson: So, currently we’re planning a phase II trial with our commercial partners, Anixa Biosciences and we’re working with their team to make sure that all the technology is there and they’re making the vaccine to the same specifications that we are, and in phase II we will be looking at efficacy. How long exactly it will take before, you know, we’d expect to see data, that’s a question for Dr. Budd.
Jamie DePolo: Okay. All right. Dr. Johnson, thank you so much. This has been really helpful and very exciting.
Dr. Justin Johnson: Thank you for coming and thank you for giving us the opportunity to speak to your audience.
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