Dr. Ivan Borrello, MD
Johns Hopkins University School of Medicine
Interview Date: April 30, 2015
Dr. Ivan Borrello, MD, PhD of Johns Hopkins shares his work to create a patient-specific immunotherapy using enhanced T cells from the patient’s own bone marrow, for truly personalized medicine. In a myeloma patient, the immune system is depressed and can no longer kill off cancerous cells. His work extracts T cells from the bone marrow in an individual patient, expands them a hundredfold outside of the body in the presence of the tumor cells, and then after an autologous transplant gives them back to the patient. When they are re-introduced, they target the hundreds of proteins that could be causing tumor growth for that patient, not just a single protein. This is the first time that T cells are being taken from the bone marrow instead of the blood in order to target the tumor cells more specifically. He compares this type of immunotherapy with the CAR T cell therapies and notes that this approach does not have the side effects found with the CAR T cell use.
The Myeloma Crowd Radio Show with Dr. Ivan Borrello, MD
Jenny: Welcome to today’s episode of Myeloma Crowd Radio, a show that connects patients with myeloma researchers. I’m your host, Jenny Ahlstrom. This is the fifth in a very important series featuring the Myeloma Crowd Research Initiative. For the first time patients, including you, are teaming up with myeloma researchers to find and fund the ideas in myeloma that could have the greatest impact for the next generation of myeloma therapies. We decided to go after high-risk myeloma because these patients have poor outcomes and few working therapies. Ultimately, if we become relapsed and refractory to current drugs out there, we also become high-risk. We were thinking that what works in high-risk will help low or standard risk patients as well.
We asked researchers around the world to submit their proposals and we received back 36 high quality letters of intent. Those were then scored by our Scientific Advisory Board and 10 proposals were selected. We’re now holding Myeloma Crowd Radio shows so that you can be involved. We would like you to understand the proposals, so please listen in and ask questions (which you’ll be allowed to do at the end of this program), read the transcript after the show is posted and share it with your friends and family. This is very critical work being done in multiple myeloma. After these proposals are submitted, the Scientific Advisory Board and Myeloma Patient Advisory Board will together decide on the number to fund through patient-driven campaigns.
Again, we will need your help to get the word out and share the really amazing work that’s being done. Here’s one way you can share today. We have a campaign open at mcri.myelomacrowd.org. We would love for you to register and start building a team of family and friends who can help support you to fund this effort. We will be posting our final selected projects in the coming months.
Now, we are delighted today to have with us Dr. Ivan Borrello of John Hopkins. Welcome, Dr. Borrello.
Dr. Borello: Hello, everybody.
Jenny: Let me introduce you before we begin. Dr. Ivan Borrello is Associate Professor of Oncology, Associate Professor of Cellular and Molecular Medicine for the graduate program, and Director of the Cellular Therapeutics Center at Johns Hopkins School of Medicine. Dr. Borrello and his team of researchers have focused on the development of tumor immunotherapy for blood cancers that use cancer vaccines as well as patient’s own immune system to fight their cancer. The particular treatments developed in Dr. Borrello’s laboratory are known as adaptive T cell therapy with MILs, which we will learn about today, and have broken new ground in the fight against diseases such as multiple myeloma.
Dr. Borrello is the widely published author of many peer-reviewed articles and book chapters and a member of several national oncology organizations and professional societies. Dr. Borrello is asked to speak regularly at symposiums around the world. He’s received many honors and awards including the American Society for Clinical Oncology Scholarship Award, the Johns Hopkins University Clinician’s Scientist Award, the Kimmel Scholar Award, and the Leukemia and Lymphoma Society of America Clinical Translational Scholar Award.
Dr. Borrello, thank you so much for joining us today.
Dr. Borello: Thank you.
Jenny: I would like to add one more individual on, Gary Peterson. He is also on our Myeloma Crowd Research Initiative Patient Advisory Board. Welcome, Gary.
Gary: Well, thank you very much. I’m glad to be here.
Jenny: Dr. Borrello, if you would like to start by just describing your proposal and maybe helping us understand what are MILs. A lot of us are not familiar with that terminology.
Dr. Borello: Sure. The proposal, as Jenny alluded to, is focusing to target high-risk myeloma with this approach that has been developed in my lab using MILs. MILs stands for marrow-infiltrating lymphocytes. These are immune cells, lymphocytes being immune cells that reside in the bone marrow. As I’m sure all of you know myeloma is primarily a disease that is limited to the bone marrow. So if one thinks about how the immune system recognizes whatever it needs to target and specifically in this case myeloma cells, it needs to target it by having receptors on the surface of the lymphocytes that recognize the proteins of the tumor, and they need to come in close contact with those tumors.
It made sense that the place in the body in which you would find the greatest amount of these tumor specific T cells would be in the bone marrow. Several years ago we actually did experiments where we took blood and bone marrow from patients and we activated these cells with beads in the laboratory and showed that upon activation there was no increase in tumor specificity or tumor recognition of the cells that were derived from the blood whereas, in contrast, the bone marrow cells or the MILs from the patients had roughly a 100-fold increase in tumor specificity. This has subsequently led to a series of clinical trials, including the one that we are currently conducting specifically targeting high-risk myeloma.
Jenny: And can you expand on that a little bit? I know, Gary, you have some questions about the beginning of describing MILs? Do you want to ask that question right now?
Gary: I was wondering, for one thing, if MILs are the same thing as CARs. And we heard in this whole immune therapy, this universe now of immune therapy about CAR and CAR T cells, are the MILs the same thing? What differentiates a CAR from a MIL? And if you could expand on that just so that we are aware. Is it same thing or is it different in some way?
Dr. Borello: Sure. So CAR stands for chimeric antigen receptor. Basically, it is, for the most part, a virus that has been modified to have two aspects to it. The part that sticks outside of the cell is generally an antibody that recognizes a certain protein. The part that’s inside of the cell of this CAR is the signal transduction: the mechanism that actually activates the T cell. So in general, it is an anti-body on the outside and has T cell mechanisms on the inside. And this virus that has this construct is then put in to a T cell. So those are what are called CAR T cells.
Up until now, all CAR T cell work has been done using peripheral blood cells, cells that have been obtained by sticking a needle onto somebody’s vein and taking out the T cells or the lymphocytes. Our approach does not involve, at this point, modifying the T cells with any kind of a virus. What we are doing is taking a different source of T cells, specifically instead of using the blood, we are using the bone marrow. And I think one of the major differences is, as I mentioned earlier, that the blood cells intrinsically have very, very little tumor specificity, whereas the MILs, in general, have a heightened amount of tumor specificity.
What we are hoping to do is to use a cell that can recognize potentially hundreds of proteins that are present on the surface of myeloma as a source of T cell therapy as opposed to a cell that intrinsically recognizes zero or very few proteins that are present on the surface of a T cell. After this gene modification only recognizes one.
As you mentioned, CARs have achieved a significant amount of interest because specifically with regards to the CARs that target CD19, which is protein that is present on a lot of B cell malignancies such as ALL or acute lymphoblastic leukemia; CLL, chronic lymphocytic leukemia; diffuse large cell lymphoma, follicular lymphoma, and some will argue even myeloma. It is only one protein. They have seen very dramatic results. Pediatric leukemia and pediatric ALL but have also seen that when the patients relapse that have been treated with CAR T cells that are CD19 targeting, that oftentimes those patients actually have a leukemia that is lacking the CD19. In other words, they have what is called technically “antigen escape variants”.
The parental tumor that expressed this protein CD19 has been effectively killed by the T cells, and now the clones that have come up are clones that do not express this, which is not all that dissimilar in what people see when they think about antibiotic resistance. And this is the limitation when you are going after one or two proteins. So what we are hoping is that when you are targeting hundreds of proteins, that the likelihood of such antigen escape variance are potentially significantly less. And so sort of summarizing, the differences between CARs and MILs is that a CAR itself is a virus that changes the proteins or changes the recognition of the T cell. MILs are a different source of T cells which could potentially be used together with CARs and the current formulation are used in the absence of CARs.
Gary: I guess the next question for me then is if these MILs — like a CAR, a CAR has to, I believe, be sensitized so that it goes after the correct myeloma cell. You did something and I can’t remember — you energized it or you did something different to it. It’s been pepped up in some way.
Dr. Borello: Yes.
Gary: I don’t know what that means. What does that mean? Another question is if we have these cells already in our system why don’t we just pull some out like they do with T cells and just multiply them and put them back in and let your own MILs do the MILing.
Dr. Borello: The MILs will do the MILing, yes. So you asked a very important question. So basically…
Gary: I do that when I lose my notes. I couldn’t find my notes. My other questions weren’t nearly as good but this is coming off the cuff.
Dr. Borello: That’s okay.
Gary: Sorry about that, Dr. Borrello.
Dr. Borello: No problem. Basically, all adaptive T cell therapy that is currently being used is having something done to the cells out of the body. The CAR technology as well as the technology that we’re currently using involves somehow turning these cells on. The reason this has to be done is twofold. One is that tumors intrinsically have the ability to poison the immune system. That is one of the major reasons why immune therapy does not work in a patient with advanced cancer because de facto the tumor has poisoned the patient’s immune system to be able to function effectively.
What we have seen over the past few years is that we are beginning now to figure out how we can reverse that process. The analogy that I like to give is that the immune system is drunk and we have to do something to sober it up. This can be done, in terms of adoptive T cell therapy, by taking these T cells out. Then in the case of what we’re doing, which is what a lot of CAR technology is also doing, is we add beads to these T cells that can stimulate the T cells. So that achieves two purposes. One is that it wakes them up. The second thing that it does is that it allows the cells to effectively expand.
So we can get about a hundredfold expansion of these T cells. Not only do we expand them in numbers, but when we look at them, they now all of a sudden are T cells that can actively recognize and kill the tumor that they are specifically targeting. The same process is done whether you’re using CARs or MILs.
Jenny: Can I ask a follow-up question on that?
Dr. Borello: Sure.
Jenny: I know the immune system of myeloma patients are compromised and are not working properly. Otherwise, they’d be able to kill the myeloma. Are the T cells that we typically have when we have myeloma, are they mutated or are they just not doing their job? Are they suppressed? What’s happening with the normal T cells – what should be normal T cells?
Dr. Borello: It’s been shown especially if you look at a disease like myeloma which from a scientific standpoint is a very interesting disease to study because as I’m sure everybody knows that there’s a pre-myeloma condition called MGUS or monoclonal gammopathy of undetermined significance. Then there’s smoldering myeloma and then there’s active myeloma. Within active myeloma there’s early diagnosed, newly diagnosed, and there’s relapsed myeloma. I think as Jenny alluded at the introduction of the talk, as patients relapse they acquire more genetic hits that de facto transform the disease into what would otherwise be a more aggressive disease.
It’s been shown that when you map this out from MGUS to smoldering, to active, to relapsed myeloma, that the patient’s immune system becomes less equipped at fighting the cancer. So in general, there’s this concept that has been demonstrated in mouse models called immune surveillance. And the concept is that our immune systems, in general, are capable of recognizing and killing tumors when they’re present at a few cell levels, so at a one, two, maybe ten or 20 cells. When these cancers arise, our immune system can most often effectively recognize it and eradicate it. And because of that, we actually see a lot less cancers than we would have.
An example of this is that if you look at patients that are immunocompromised, so, for example, patients that have AIDS or patients that have undergone a solid organ transplant, that are on chronic immunosuppression such as cyclosporine or tacrolimus or other drugs like that, their likelihood of developing secondary malignancies is much higher than in somebody that has an intact immune system. So that really proves the point that we do have, our bodies normally have this process of immune surveillance, of having our immune system sort of go around our bodies and attack these few cell cancers that are forming. And when these escapes occur that we then develop clinically detectable cancers.
So how does that occur? Well, that can occur through a variety of reasons. One aspect of it is that the cancer is just growing much quicker than the immune system is capable of recognizing, and therefore you get clinical outgrowth. A second aspect on that is that the cancer itself is capable of effectively poisoning the immune system to dramatically reduce the ability of doing immune surveillance. Another aspect is that the cancer itself can mutate in a way that it’s capable of effectively evading the immune system.
And so, there are multiple mechanisms that really play a role. But what has come out and is becoming more and more clear is that a lot of this is an interplay of the tumor with its microenvironment of which the immune system plays a significant role.
Jenny: Do you want to talk about that for a minute? Because I know we’ve had chosen in the past to talk about the importance of the bone marrow microenvironment and the things that are happening in there will either shut down the growth or expand the growth. Do you want to address that?
Dr. Borello: Sure. So I think the tumor microenvironment and the role the tumor microenvironment plays is increasingly being recognized probably as being as important, if not more important, to really understanding the biology of the tumor itself. An example of that especially in myeloma has been worked on by several groups where they have actually shown that one of the things that allows a myeloma cell to survive its ability to attach itself to the stroma, which is basically the infrastructure or the scaffolding, if you want, of the bone marrow and the mere ability of a plasma cell to attach to this scaffolding intrinsically confers chemo resistance.
So in experiments that were done, if you take a bone marrow, if you take a plasma cell and you have it just floating around and they are a liquid cell so they can float around, you can kill it, let’s say, with ten milligrams of drug x, if you take the plasma cell and attach it to the bone marrow stroma, the scaffolding, now ten milligrams of that drug x are no longer capable of killing the tumor. You now need to go up to 100 milligrams. These experiments have been shown over and over again. And so one aspect of it are these cell adhesion molecules that are capable of conferring chemo resistance.
Other aspects of it are the role that the immune microenvironment plays. The T cells, we’ve talked about how to use them to fight the cancer, but we’ve also published work showing that what happens within the tumor microenvironment is almost a triangulation that the plasma cell itself can produce certain proteins that ultimately cause the T cells to produce other proteins that are basically responsible for the bone destruction that is not uncommon in multiple myeloma, the thing that ultimately causes lytic bone disease and that, in fact, a significant amount of the lytic bone disease that we see in myeloma is in large part driven not by the tumor itself but by the immune system, by the bad immune response that the tumor actually elicits. Being able to block that can be critical in terms of preventing bone disease.
There are other cells in the bone marrow that have been shown and these are also immune cells called the MDSCs or myeloid-derived suppressor cells. These cells have been shown to be able to transform themselves within the myeloma microenvironment into osteoclasts which are cells that actively destroy bone. And these MDSCs are also cells that can confer chemo resistance to the plasma cells themselves.
So these are all things that when you take the totality of the environment in which the myeloma cell is living I think allows for an explanation for some of the discrepancy as to why a lot of clinical papers that basically just take plasma cells and put them in a tissue culture dish and show how drug x is so effective that when you then go into in vivo systems whether it’s mouse models or human clinical trials, tend to oftentimes give only a fraction of the benefits that were seen with a lot of these pure in vitro models.
Jenny: And that would explain why some patients have extreme bone damage and some patients don’t have that much bone damage?
Dr. Borrello: Well, it’s hard. So we published a study where we actually looked at — so we looked just by X-rays that how much bone disease was present in patients. So we graded it zero through four with zero being nothing and four being a ton of bone disease. And then we actually looked and said, how much myeloma do these patients have and were there differences? And we showed that there absolutely no differences in the amount of tumor in patients with zero bone disease versus four plus bone disease.
But when we looked at the immune response of these bad cells, we showed that one specific protein — and in our case it was this protein called interleukin 17 or IL-17 — that that together with a whole bunch of other proteins that go along on that pathway was highly predictive of the development of bone disease in these patients. So one of the interesting things, for example, of the MILs is that as we activate these MILs, we actually completely shut down this IL-17 pathway and turn on another pathway, which is called the gamma interferon pathway. And the gamma interferon is very effective in reducing or in poisoning osteoclast formation, osteoclasts being the cells that induce bone disease.
Jenny: Well, there’s a lot happening in what you’re trying to do. Maybe it would be better to take a step back. I know that myeloma is considered a very heterogeneic, or there’s a lot of heterogeneity, I guess, which means all patients can have multiple types of myeloma in their cells. And what I hear you saying is that as opposed to the CAR T cell where they are attacking one protein, this approach would be more able to target maybe hundreds of different types of proteins.
Can you go into a little more detail about how that works? And then I think we’ll go through the process of how you’re using high-dose chemo with the MILs.
Dr. Borello: So in terms of making a therapeutic MILs product, as I mentioned, we really started off in a very simplistic manner trying to take advantage of the natural biology and the idea being that these T cells that reside in the bone marrow are intrinsically myeloma specific, but they’re not effective. What we showed is that in order to make a good product, we actually need to be able to grow these cells in the laboratory, in the presence of tumor; that the presence of tumor as these cells are being activated and expanded can actually drive the tumor specificity of these MILs towards greater myeloma specificity.
In terms of the exact proteins that they’re targeting, we don’t know. We’re beginning to look at this. But the idea is that they’re going to be targeting anything that’s present on the surface of the myeloma cells. So if you have a patient with high-risk myeloma, presumably the proteins that are being expressed on the surface of his or her tumor are going to be proteins associated with the high risk-myeloma. In contrast, somebody with a low risk myeloma, for example, will have a different set of proteins.
I think when one looks at the entire repertoire of immune proteins that can be found in myeloma cells, I think it’s probably fair to say that maybe 60% to 80% of them would be what we will call common shared antigens or proteins that are present on all the patients. And then each individual will have his or her unique antigens or proteins that will define their disease and set his or her disease apart from everybody else’s. By taking an autologous approach or a patient-specific approach, hopefully as many of these different antigens or proteins will be recognized and will be primed, and so we will therefore be able to develop a MILs product that can recognize as many of them as possible through this process of T cell expansion.
Now, in terms of why, we would ultimately give this in a setting of a transplant. That really is based on another biological point. I think most of you are aware of the fact that if you chop out somebody’s liver, it will grow back to its normal size. I mean this was described in Greek mythology and certainly has been proven in a variety of different situations. Basically, the concept there is that there is a pre-defined size that our body has for a liver. It turns out that that same concept also exists when you think about lymphocytes or the immune cells; that there is a defined range of lymphocytes that are present in our body.
If, for whatever reason, too many of them go in, then our body stops producing lymphocytes to bring it down into the normal range. In contrast, if we don’t have any lymphocytes, a body produces a whole bunch of proteins that allows us to bring us up to the normal range.
So one of the things that I think is unique to a lot of hematologic malignancies such as myeloma that really allows us to super impose immunotherapeutic protocols very nicely is the fact that bone marrow or stem cell transplantation is a therapy that is widely used in a variety of these different diseases including myeloma. As I’m sure everybody knows, with a stem cell transplant, patients get high doses of chemotherapy that completely wipes out their bone marrow, their blood counts basically fall down to zero.
Most people are focused on how long it takes for the neutrophils to recover because those are the cells that ultimately allow them to fight bacterial infections and to get them out of the hospital. But it turns out that in addition to the neutrophils falling down to zero, the lymphocytes also go down to zero. That becomes a situation in which, as an immunotherapist, we can take advantage of that because if we put in lymphocytes such as MILs or even CAR T cells into a setting in which basically that overall number is zero, there are going to be so many proteins in circulation that are sending signals to increase the number of lymphocytes that we can allow nature to further expand the product that we have just put in.
Basically, we are expanding the product two times. We’re expanding them ex vivo in the lab as we’re giving these beads and allowing these cells to grow. And then we can put them into the patient and allow them to expand even more by virtue of natural processes that are associated with a patient that’s undergoing a stem cell transplant.
Right now the trials that we have going on focuses on integrating this adoptive T cell therapy with MILs in the context of a transplant, but I think it will easily be possible in the future to do this with a therapy that will wipe out the lymphocytes but not necessarily wipe out all the blood cells. In other words, we could possibly do this giving a reasonably high dose of chemotherapy but not necessarily having patients undergo a stem cell transplant or a bone marrow transplant.
Jenny: But for now, you’re using transplant to get there, right? This will be in the future?
Dr. Borello: Yes. Correct.
Jenny: Okay. Well, I think patients everywhere would love different approaches using immunotherapies and a combination of what’s out there.
Dr. Borello: Absolutely.
Jenny: — and a combination of what’s out there. So let me go back and ask you about the individualized nature of this. So in your process, you’re taking some bone marrow T cells out and then you’re engineering them on an individual basis. You’re giving high-dose chemotherapy for the transplant, and then you’re giving them back to the patient. So this is all particular to the individual patient? Maybe you can clarify.
Dr. Borello: This is a patient-specific product. Patient x comes in and gets his bone marrow done to collect the MILs. The cells are expanded, then the patient starts the transplant, and then days three and four after the transplant they get their own cells back. So everybody has to get his or her own cells taken out and then gets his or her own cells put back in.
Jenny: Well, that’s amazing. And for the bone marrow collection, what’s involved in that?
Dr. Borello: So it’s a bedside collection. We basically have to collect 200 MILs of bone marrow which sounds like a lot and it is a lot. But we do this by giving the patients conscious sedation and so they’re awake. It’s sort of like what patients get when they get a colonoscopy. They’re in a twilight zone.
Generally, the way we do this is I go in together with another individual and where each one of us is on one side of the patient. We go into the bone marrow on both sides, and we collect the 200 MILs of bone marrow which the time in the bone marrow to collect this volume of bone marrow is about 10 to 15 minutes. But the whole procedure to get set up, to get the drugs, to get monitored is about an hour; but it’s outpatient.
Jenny: And then they go through the collection process. How many days past the transplant do you give these cells back?
Dr. Borello: We’re giving them back on days plus three and plus four, so that’s three and four days after the transplant.
Jenny: When they go back into the patient and they expand, for how long are they active? I know in some of the CAR T cells they are saying that could be present for up to a year or more. Is that same with how these work?
Dr. Borello: I can’t tell you for sure. The reason why they can tell you that was CAR T cells is because the T cells are basically gene modified. So they can pull the cells out and actually look for the gene and say, “Okay, now, out of these 1,000 cells, 50 of them are the CARs.” We are basically taking cells out, just expanding them and putting them back in, we’re not gene marking them in any way.
But I can tell you that — and our first paper’s going to be coming out at the end of May — where we looked at the tumor specificity of these MILs and we were able to show that in the first trial that we did, that the tumor specificity of these cells peaked at six months but was still detectable at one year out from transplant. The overall clinical benefit from the whole trial which is transplant plus MILs correlated with the degree of immune recognition that these MILs have.
So in other words, the greater the myeloma specific immunity that was generated by the MILs, the higher the likelihood was that these patients achieve the complete remission. So again, we could still detect some of that at one year, but I couldn’t tell you for sure whether those were the cells that we put in or those were also cells that were being generated de novo following the transplant of the patient.
Jenny: Well, what I love about it is this it’s truly personalized medicine where you’re targeting exactly what’s present in that particular patient. So you don’t have to worry about maybe missing cells that don’t have a certain target on them and those are the cells that now grow. You’re trying to attack everything at the same time.
Dr. Borello: Correct. That’s exactly right.
Gary: Doctor, along that line, these MILs, they are not modified in any way because in your presentation you mentioned that they’re activated.
Dr. Borello: Right.
Gary: You actually said there are aMILs, meaning that seems like they’re somehow different than the MILs that you have in your system. So I was wondering, so they’re really not activated, they’re just expanded. Is that correct?
Dr. Borello: Well, I mean activation and expansion, two different words to describe the same process. But they’re not modified in the sense that we are not to sticking any proteins into the cells. I mean if look at the DNA of the cell before and after we activate these cells, they’re the same. The only difference is that they’ve undergone this expansion with these beads that has resulted in turning them on.
Gary: Okay. What we heard about on CAR T cells like on the CD19, for example, is that there was some on target and then some unfortunate off-target implications. And these off-target implications almost killed some of the patients. You don’t have that issue here. Is that what I’m hearing?
Dr. Borello: Correct. Right. You raised a very interesting point and one that I want to elaborate on if I may. So the CAR T cells, at least the CD19 ones, that have been used in leukemia have been associated with very dramatic reductions in tumor burden within weeks. They have some very nice data showing that basically the tumors can disappear. But what that’s also associated with is this process called the cytokine release syndrome which is making patients extremely sick. They’re ending up in the ICU on a significant amount of drugs. Unfortunately, in a few cases, patients have even died from the therapy itself. The fact is that this is because these T cells are hyper-activated and they’re doing what they’re supposed to be doing. They’re just doing it too well.
But I think one of the limitations, therefore, of CAR T cells in the current formulation is that this is a therapy that is really limited to people that have very few options because the morbidity of this is so high and mortality is so high. What we’re seeing with our MILs is that these patients are getting some fevers, they’re getting diarrhea, they’re getting skin rashes, which are the kinds of things that they’re seeing with the CAR T cells. But for the most part, it’s a very mild form of it and it has been self-limiting in every single situation.
In other words, we have not had to treat anybody for any of these symptoms that have received MILs. I think in the current formulation of the MILs, we can certainly use this as upfront therapy. In fact, the trial that’s currently ongoing and being funded by the Leukemia Society is one in which we are giving these cells to patients that are getting an autologous transplant with high risk disease in first remission. So a patient is being diagnosed. Getting their four to eight months or whatever it is of chemotherapy and going to transplant with these MILs.
Gary: Are you saying they’re doing that? Is it being done right now? I thought everything previously has been done in vitro?
Dr. Borello: No. We have completed two trials at Hopkins that were not specifically targeting high-risk patients. We’re just targeting anybody that was potentially eligible. But now we currently have a trial open that is a trial that’s a randomized trial for patients with high-risk myeloma. If they meet those criteria, they’re getting their MILs harvested and they’re being randomized in a two to one manner to either getting MILs with the transplant or not. But the patients that are on the no MILs arm are eligible to get the MILs at the time of relapse. This trial is going to be open in the next few months also at Moffitt in Tampa, Florida as well as the Mayo Clinic, Jacksonville also in Florida.
So there will be three sites that will be involved in this trial. So the goal is to treat 90 patients and to see whether the effects that we’ve seen so far hold up in a randomized trial like this.
Jenny: In the randomized trial, when they can get the MILs at a later time at relapse, do they do that with a transplant or by themselves?
Dr. Borello: No. That’s a very good question. So getting to this concept that I mentioned earlier about having to get rid of the lymphocytes, what we’re doing for the patients that have relapsed is that we’re just giving them an intermediate dose of Cytoxan which is chemotherapy. And what that does is that that causes a significant reduction in the lymphocytes. We call that lymphoablation. And then that’s being followed by the infusion of the MILs. So that is a non-transplant setting.
I think from a patient perspective, the appeal of a trial like this is that everybody is getting the MILs. They’re just not all getting it at the same time. So it allows us as researchers to really answer the question of what the therapeutic efficacy is of these cells. But it also allows us to answer another question and that is do we really need a transplant? And can we get by with just giving a dose of chemotherapy with the MILs in the absence of transplant?
Jenny: I’m very curious. What led you to study this in the first place? How did you develop this work?
Dr. Borello: Yes. So that’s also an interesting question. I’ve had a longstanding interest in immunotherapy. Starting off back in 1997 is when I sort of started working in this field. We did a few trials. One of them was a trial using the beads that we’re currently using to activate the T cells but using them by expanding peripheral blood lymphocytes. And this was done in collaboration with a company that now no longer exists, but the idea was that the patients were getting their lymphocytes collected. This product was being shipped off where the cells are being expanded using the same technology that we’re using currently and then it was being shipped back.
What I saw was that this was a very effective way of increasing lymphocyte numbers, but it lacked tumor specificity. These cells didn’t target anything. And so we started thinking there’s a lot of evidence in the solid tumor literature that TILs exist or tumor infiltrating lymphocytes. And it’s been shown, for example, in melanoma and colon cancer and ovarian cancer and breast cancer that if a patient has a tumor that has lymphocytes infiltrating the tumor, their overall outcome is better than if they have a tumor without lymphocytes really I think underscoring the potent anti-tumor effect that the immune system can deliver.
Furthermore, there is work being done at the National Cancer Institute where they take patients with metastatic melanoma, the skin cancer, and they take out these TILs and they grow them up. We hypothesized that if solid tumors have TILs that are intrinsically tumor specific, maybe patients with blood cancer such as myeloma might have MILs, which is why we coined this term MILs or T cells that are infiltrating the tumor that may be tumor specific or in this case, the bone marrow.
So that was the genesis of what led us to these initial experiments. Basically, we started those experiments in 2004 or something like that. Here we are roughly ten years later, now in our third clinical trial. We still have a lot of work to do to move forward. I mean there are still things that need to be improved upon. But I think the biology behind this is very strong. With each trial and with each experiment, I think we’re making better products and are understanding better and better what we can do to turn this into better cells.
Jenny: Because you’ve already done research on this and you mentioned that it’s been done with other cancers but specifically for myeloma, have you seen effects or changes to the bone marrow microenvironment after doing this?
Dr. Borello: Yes. So patients getting transplant that get the MILs have a much quicker immune reconstitution in their bone marrow than patients that don’t. We’re seeing that just recovering from transplant, patients don’t have the kinds of infections that are normally associated with transplant as patients that aren’t getting MILs. We’ve seen more of this tumor specificity. So we’ve seen patients that have had clearance of the tumor. The interesting thing is oftentimes what we’re seeing especially now in this third trial, this current trial of high risk, is that we will see a small increase in the M spike of these patients that will then be followed subsequently by a nice decrease.
One of the things that we’re really focusing on is to try to come up with strategies. I think we might have it with this current trial of allowing durability of the response. In other words, we want to make sure that not only can these patients go into remission or complete remission hopefully, but that they can stay it for an extended period of time.
Gary: Along that line, in these trials, of the people who you had previously that weren’t high risk, just normal myeloma patients, what were the results of that, a complete response, that kind of thing or better yet, did you use minimal residual disease measures?
Dr. Borrello: In our first trial, which is really the only trial that I can talk about because that’s the only one we’ve analyzed so far, we specifically excluded patients that had achieved the complete remission going into the trial. So anybody that was in complete remission was not eligible for the trial. If one looks at overall outcomes of patients with myeloma that get transplanted, the best predictor of a complete remission post-transplant is being in a complete remission pre-transplant. In a way, we were sort of skewing the data away from that.
So what we saw is that we got roughly somewhere — I don’t know the numbers exactly but I think it was between 35% and 40% complete remission rate from the patients in that trial. I think that remission rate was actually higher than what we would have expected but what we didn’t see was durability of the response in that first trial. So we subsequently modified the second trial, which was a trial that was randomized between getting a vaccine in addition to the MILs versus not getting the vaccine. In that trial we also gave roughly tenfold more T cells. In that trial we saw a higher complete response rate and a longer duration of remission. But as I said, we cannot tell you the details because we have not analyzed it yet.
Gary: Were these newly diagnosed patients or —
Dr. Borello: No, they weren’t. The only criterion for this trial was that the patients had to have never had a prior transplant. In the first trial, I think about 60% of the patients were newly diagnosed but then 40% weren’t. And the median number of prior therapies was around three. So there were some patients that had had six prior therapies before going into the transplant. In our second trial, the median number of prior therapy was lower because we also took patients who were in a complete remission.
Gary: Do you have any overall survival data or anything like that?
Dr. Borello: From the first trial we do, the median overall survival data I think is in the order — actually, I don’t know for sure. I don’t want to say something that ends up being wrong. But it is going to be coming out in a month. I don’t have access to data right now so I don’t remember what it is. But I will tell you that in the first trial we had a significant number of patients that relapsed within the first year of transplant and our current high-risk trial, which is technically a higher risk patient population, we have now transplanted about 25 patients. Taking both patients that got MILs as well as patients that didn’t get MILs, out of these 25 we’ve only had three relapses and the median timeout is now about a year and half.
So we are seeing overall a much better clinical outcome at least from this very preliminary overview of what is going on compared to what we did in the other trials. This is actually almost historically approaching I think what would be something that would be better than would be expected considering the high-risk patient population that we are actually trying to treat.
Jenny: Well, let us talk about that for a little bit. So this is basically your third clinical trial, correct?
Dr. Borello: Yes.
Jenny: With this and it is specifically for high-risk patients. Which high-risk patients are you looking for, for this study?
Dr. Borello: Currently, the criteria for high risk are primarily based on the classic ones which is FISH. So it is the 1Q amplification, 1P deletion, 4;14, 14;16, 17P as well as an LDH greater than 300, and also potentially patients that have relapsed from their initial induction therapy within 12 months of diagnosis. Then what we are doing is at the time of the bone marrow, we are also sending the bone marrow off for gene expression profiling using the Signal Genetics test, the MyPRS. We are randomizing patients based on whether they have high risk per the MyPRS. So technically, everybody has high-risk so you can either be high-low, if your gene expression profiling is low, or you would be high-high if your gene expression profiling is high.
And so patients are being randomized so that we will have an equal representation of these high-high risk patients in both groups. If somebody comes in with the gene expression profiling that’s high, they would automatically be eligible regardless of what their FISH shows. For example, I have a patient that has good-risk FISH, they have an 11;14 translocation, but they have high-risk disease based on the MyPRS, and so that patient is eligible for the trial as well.
Jenny: How about other patients who have — I mean this is not just for newly diagnosed patients, right? Or is it?
Dr. Borello: No, not it is not, as long as they have never had a transplant.
Jenny: So if they have had a transplant, they cannot participate?
Dr. Borello: Correct.
Jenny: You don’t look at the M spike as far as your criteria?
Dr. Borello: Nope.
Jenny: They can be non-secretory or something?
Dr. Borello: Well, they have to have something that is measurable. So they might not have an M spike but if they have, for example, serum free light chain, they would be eligible, as long as there is something that we can measure.
Jenny: Gary, do you have other questions? I’d like to open it up for caller questions if…
Gary: Yes, open it up please.
Jenny: If you have a question for Dr. Borrello, you can call 347-637-2631. Please go ahead with your question.
Caller: Hi, Dr. Borrello. Thanks so much for taking my call. I’m a smoldering myeloma patient. So I’m trying my very best to follow along. I thank you for being so detailed and descriptive which has actually helped me to better understand all of this, even though it is very, very complicated.
I have a question though for you based on an interview that Jenny did last week with Dr. Paiva. He indicated that there are myeloma cancer stem cells which contribute to myeloma relapse. But you also indicated that these cells have actually yet to be identified. Therefore, it is not yet known what, if anything, can target these cells. So theoretically, would your treatment target these cells that contribute to myeloma relapse?
Dr. Borello: That is a very, very good question. So I can tell you that this whole question of cancer stem cells is another very hot topic right now in the field of cancer research. And there’s a colleague of mine here at Hopkins, Dr. Matsui, who has done work in identifying a cancer stem cell for myeloma. Dr. Paiva is right. We don’t know for sure, but there have been some work, including the work done here, that has suggested that the myeloma stem cell is a CD138-negative cell. So the plasma cells and myeloma cells are expressed as a CD138, but that the stem cell is CD138-negative. Actually, it is more like a B cell, which is the parent cell from which plasma cells derive.
In our first publication we actually used his assay where he can basically take bone marrow and deplete it of mature plasma cells. Basically, all he has are B cells there and grow out ultimately myeloma cells that look exactly like the original myeloma cells, suggesting that this CD138-negative cell may in fact be capable of generating progenitors or offspring that are the plasma cells. We used this assay and we added activated MILs. We added MILs to this assay and showed that in the presence of these MILs, we got about an 80% reduction in the outgrowth of myeloma, suggesting that the broad specificity that these cells cover, that these MILs cover or recognize may also include antigens or proteins that are present and that can target the myeloma stem cell.
This is the extent of the knowledge that we have. But I think theoretically the fact that we are taking this from the bone marrow and that these stem cells also reside in the bone marrow is one thing that may be suggestive of the fact that they may have recognition also to the stem cells.
Caller: Thank you so much for explaining that.
Dr. Borello: You’re welcome.
Caller: That is really certainly a lot of hope to every myeloma patient that is likely listening to your interview today.
Dr. Borello: Well, thank you.
Caller: I wish you the best of luck and thank you again.
Dr. Borello: Thank you very much.
Jenny: Thank you so much for your question. Thank you. This sounds like a very broad approach as opposed to a highly targeted approach. I think the highly targeted approaches are great except that myeloma seems like it is so complicated and so wily in nature where you knock it down in one place and then it grows in another place. It sounds very exciting to me that the approach can be more broad and very personalized.
Okay, we have another caller. Go ahead with your question.
Caller: Hi. Thank you for taking my call. I have a couple of questions. My first one is if a patient is to get into this trial, do they need to travel? What is their actual clinic commitment to participate over the long haul?
Dr. Borello: It is a transplant. Basically, you do need to travel. You need to go to one of the sites that are open. We are the only site that is open but hopefully there are other two that I mentioned in Florida that will be opening within the next few months. So you would need to come here to be seen initially, to be screened for eligibility. Then you would need to come back to get the bone marrow harvested, and then you would need to be here for the transplant which is roughly about three to four weeks of staying here in Baltimore, which might not be the right place to be in right now, but it is getting better or one of the other sites.
Caller: Okay. If the patient is having economic problems, is there some kind of assistance for travel?
Dr. Borello: No, there isn’t, unfortunately. No, I’m sorry about that.
Caller: By the way, I love Baltimore so I am sure it will be fine to travel there shortly.
Dr. Borello: It is a wonderful city.
Caller: It is. I love it. Do you think this kind of treatment can eventually — I mean, for example, if you add bortezomib or dex, do you think that adding those additional medications might improve the outcome?
Dr. Borello: That is also a very good question. I would argue, no; and I’ll explain why. In fact, what I did not mention is that in our current trial we are giving patients lenalidomide starting at two months afterwards for two reasons. One is that it has anti-myeloma properties and there’s clearly got a lot of data to show how, given as maintenance therapy, improves outcomes of patients undergoing an autologous stem cell transplant. But the second reason, and potentially the more important one, is that it is also immunomodulatory. It can augment T cell function and maintain T cell function. So we are hoping that by the addition of that we can basically maintain or expand the lifespan of these MILs.
In contrast, bortezamib and steroids actually kill lymphocytes. If you are trying to come in with a therapy that is trying to elicit an immune response, you wouldn’t want to give drugs that would then blunt it dramatically. And so we are not allowing for those two drugs to be used after the MILs are infused. Now, before the MILs, patients can get whatever they want. But once they get these MILs, then they are not allowed to use either steroids or proteasome inhibitors such as bortezomib or carfilzomib.
Caller: Okay. One last question, how quickly can you start recruiting patients?
Dr. Borello: We’re recruiting. We are actively recruiting patients.
Caller: Oh, okay. Sorry I missed that. Thank you.
Dr. Borello: No, that’s okay.
Caller: Thank you very much.
Dr. Borello: You’re welcome.
Jenny: An additional question that I have, I actually have two more questions. So the induction would be just the standard induction therapy that you traditionally use for a transplant, right?
Dr. Borello: Yes, it is a dealer’s choice, whatever the patient is on.
Jenny: Okay. And then could you include post-transplant on any other (ultimately and maybe not in this tria)l but another kind of immunotherapy like daratumumab or something else?
Dr. Borello: Yeah, absolutely. As you said, in this trial we are currently not including it. But we certainly could envision something like that, absolutely.
Jenny: Well, could you give us an idea and I’ve asked this question of everyone that’s been participating in this MCRI series — just an idea of your timeline, the different milestones and then the budget requirements that you would be looking for or that you would need to make this happen?
Dr. Borello: Are you talking about in terms of the proposal?
Dr. Borello: So the proposal that we are looking at is really taking advantage of the samples we are getting from this clinical trial to really try to understand what are the specific antigens that are being identified and how we can basically make a better MIL moving forward. In a way, it is really focused on transitional work coming from the clinic back to the lab. The timeline for doing this with the advantage that we have is that we already are more than a third into the trial and so we already have samples we can be working with.
I think that we could begin to develop and to obtain some reasonable data as early as a few months from now based on some of the things that have been proposed. But more definitive data in terms of making CARs which is one of the things that I would like to do, to make CARs that are specifically targeting high-risk myeloma patients by using MILs as the source of the T cells. That would probably be something that would take as long as two to three years from initiation of the work.
Jenny: Sometimes it costs thousands and millions of dollars to do these studies, and sometimes it takes a thousand dollars per patient. Do you have any thoughts about how much would be required to continue that aspect of your research?
Dr. Borello: You know what, I don’t right now. I’m sorry. I just don’t want to throw a number because I need to think about this a little bit more. So I don’t have a clear figure in my head right now.
Jenny: Well, Dr. Borrello, this interview has been extremely enlightening. We are so thankful that you are working on this. We’re thankful that you are looking for this broad approach to help not only high-risk but relapsed/refractory patients and ultimately all patients.
Dr. Borello: Well, thank you very much. Thank you for the opportunity to allow me to explain all of this to you and to your audience.
Jenny: Well, it is so helpful to know the details on what you are trying to accomplish. We are cheering you on. We are very excited for you.
Dr. Borello: Thank you very much.
Gary: One point that I might get a little clarification from. At the very end of what you just said, doctor, you said that you want to develop CAR T cells that use the MILs as the target?
Dr. Borello: No. MILs as the T cells source.
Gary: As the source. So is it going to have a CS1? What is the target?
Dr. Borello: That’s exactly where I think this proposal differs from what’s currently being developed and that is that what I’m saying is I don’t know what the target is. I would like to find it based on the work that we would do from the samples obtained in this clinical trial and to come up with potentially a novel target. I mean CS1, BCMA19, CD38, these are all currently being used and being developed and potentially going to be very promising.
But none of these are specifically targeting high-risk myeloma intrinsically because these are just antigens, these are just proteins that are expressed everywhere. What I’m hoping to find is something that’s new that we could specifically say for high-risk disease which I think we all recognize currently is an unmet need – this specific antigen or this specific CAR may make a unique impact.
Gary: So you’re suggesting that there is something on these MILs that would be a target that is going to be the homerun for high-risk multiple myeloma?
Dr. Borello: Well, I’m not going to say it is a homerun, but I certainly would hope that would make a major impact. It would be nice, but I don’t think so.
Gary: Well, you are providing a far smaller universe of T cells – ones that are highly activated for that cancer. If there is something on the surface that you can activate these CAR cells with, then it looks like it would have a big impact if it exists.
Dr. Borello: Yes, absolutely. But it does exist. We just have to find it. It definitely exists. This is a different disease so it exists.
Jenny: Right. At that point, once you have your data back, you could probably segment the difference between maybe a deletion 17 patient, what target they might hae versus a 4;14 patient and what target they might have. They might be totally separate.
Dr. Borello: Absolutely.
Jenny: Okay, great.
Gary: Very, very interesting, doctor. Thank you so much.
Dr. Borello: Well, thank you.
Jenny: Thank you so much for participating in this show. We are very, very grateful for your work and all you’re doing.
Dr. Borello: Thank you very much. I appreciate it.
Jenny: Thank you for listening to Myeloma Crowd Radio and the new MCRI series. Patients can help support the discovery of a cure and we encourage you to become more involved.