Dr. Leif Bergsagel, MD of the Mayo Clinic shares the impact of the MYC translocation in myeloma progression and relapse and a new target that boosts immunity while impacting myeloma cells

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Originally posted on mPatient Myeloma Radio

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Dr. Leif Bergsagel, MD
Mayo Clinic Scottsdale

Interview date: March 7, 2014

Summary

Dr. Leif Bergsagel shares his deep expertise in the genetics of myeloma. He describes best treatment options for patients with 4;14 tranlocations and unique characteristics of 14;16, 14;20 and hyperdiploidy myeloma.  He shares a fascinating history of his work on the MYC translocation (present in almost half of all myeloma patients) and his belief that MYC can change MGUS into active myeloma and make myeloma relapse. In order to detect MYC, gene sequencing tests need to be used as the FISH test can’t pick all of it up. He explains the difference between primary and secondary mutations and details how certain genetic mutations respond to existing and newer therapies. He describes a new target now in clinical trial at the Mayo Clinic called LCL161 that boosts the immune system to activate the NFkB pathway and how that is now successfully being used in a Phase II trial. He gives a history of how he came to find this target and why it works so well (and makes patients feel good at the same time). 

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Full Transcript
Jenny: Welcome to today’s episode of mPatient Myeloma Radio, a show that connects patients with myeloma researchers.

I’m very happy to be a cheerleader for our participation in clinical trials, and I’m humbled every time I do an interview like the one today with such amazing researchers that are moving this field forward. They deserve our support. We may or may not be able to donate money to their research but if we can, we should. We can always ask our doctors about clinical trials that are being run and find one that is right for us. So this helps us and it helps to find better therapies and a cure for this currently incurable disease.

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There are articles about myeloma news, profiles of myeloma survivors, a calendar of all the myeloma events, a directory of myeloma specialists, information about diagnostic testing, clinical trials, patient support groups, Twitter feeds to follow and lots more.

Now, today, we are very privileged to have Dr. Leif Bergsagel of the Mayo Clinic in Scottsdale, Arizona. Dr. Bergsagel is a professor of medicine in the Department of Biochemistry and Molecular Biology at the Mayo Clinic. He is also the Section Head of the Lymphoma and Myeloma Section in Hematology Faculty leading a selection of research topics and literature review.

Dr. Bergsagel is a member of the scientific advisory board of the MMRF and is a fellow of the Royal College of Physicians. In the Bergsagel lab, he studies the molecular pathogenesis of multiple myeloma. He and his team have cloned more than 35 translocation breakpoints and identified five frequent translocation partners that are present in almost a half of the patients with myeloma. These translocations look like initiating events that trigger the tumor growth process and are even present in MGUS. He is a researcher with a prolific number of papers that describe the molecular detail and now risk stratification of myeloma.

So welcome, Dr. Bergsagel.

Dr. Bergsagel: Well, thank you very much. It’s a pleasure to join you today.

Jenny: Now, your deep research to risk stratified patients; I just read your paper that was published last year about how to classify and stratify risks. Can you just share what your study goals were and then what you found?

Dr. Bergsagel: Sure. My interest in this dates back to shortly after I finished my fellowship in oncology in the early ’90s. That was a time in the treatment of myeloma it was very discouraging. We hadn’t had any new drugs for decades and the survival and outlet for patients really wasn’t very good. One way I thought to approach that was trying to understand more about the biology of the disease and really understand what drives it. And so starting back then I really focused my efforts on trying to identify the genetic events that lead to multiple myeloma, which led to identifying chromosome translocations and pulling the breakpoints and finding the genes involved.

With that, so that the first fallout from identifying these, it was clear that it broke up patients into different groups that really the patients that share the same chromosome translocation share a number of other features that make them behave the same and respond similarly to drugs and have outcomes which are really much more homogenous. So that’s one reason why the chromosome translocations are so critical when we evaluate patients with myeloma because it can tell us a lot about their biology and about what to expect with treatment.

And so identifying the prognostic significance really has been the work of many investigators in the field across the world to look at the translocations and determine the outcome of patients and correlate that with the treatment. And then we’ve tried to summarize that and make a conclusion as to what we think is important and what should be done based on those findings.

If you had to sort of break it down really simply, there are a few genetic features which portend to poor prognosis and those are the ones that we mostly look for. One of the most common would be the chromosome (4;14) translocation. And then the next would be the MAF translocations, which are chromosomes (14;16) and chromosomes (14;20). And then the final one would be deletion 17p.

Those group of patients in general have a worse prognosis than the remaining patients. Then the remaining patients also have characteristic genetic features, but we sometimes don’t think it is important to look for that because mostly we’re focused on identifying things that portend to poor prognosis. But the remaining patients would often have hyperdiploidy, which is too many copies of the chromosomes. Instead of 23 pairs, they might have 24, 25 or 26 pairs of chromosomes. And the other one is a chromosome (11;14) translocation.

We’ve taken that sort of genetic characterization of myeloma identifying the high-risk patients. And then we’ve looked and seen how have they done when they received lenalidomide or how have they done when they’ve received Velcade.

So what we find is that in general the new drugs like Revlimid and Velcade had helped all patients with myeloma, but the Velcade, in particular, has made the biggest difference for patients with (4;14) translocation. It’s really quite clear that in the initial treatment of patients with myeloma, if they have a (4;14) that their survival is much better if they receive Velcade from the time of diagnosis. And that’s been shown in several studies.

Sometimes in some studies the survival of the patients with (4;14) approximate that of the patients with the good prognosis, the (11;14) and in the hyperdiploid patients; and sometimes it doesn’t quite get that high but it gets much closer to it with the use of up-front Velcade. So of all the things, I’m going to say this probably, the one single thing that seems to be the clearest and the most important. But then there’s some evidence that again for the patients with (4;14) that maybe prolonged use of Velcade either by itself or with thalidomide as a maintenance thing may also be particularly helpful.

Really there’s conflicting data and it’s kind of hard to generalize, but the single perhaps most important study that addresses that actually comes from the University of Arkansas where they used a relatively complicated regimen with many drugs and two transplants. But they did a study before the availability of Velcade. And then when Velcade became available, they kept basically the same study and just added in Velcade. You’re able to compare the outcome of patients in the first study, which was called Total Therapy 2; and a second study, which was called Total Therapy 3 and imagining that the only difference really was the addition of Velcade in those patients.

In that study, the outcome of the patients with (4;14) when Velcade was added dramatically improved so that it was the same as the good prognosis patients. Whereas the outcome for the other patients with poor prognosis, the (14;16), (14;20), the deletion 17p didn’t really change. So it was kind of a nice control group. That study I think has been very influential in our thinking about the fact that the (4;14) really is different and for reasons honestly we don’t really understand that the Velcade is particularly important for the patients with the (4;14) chromosome translocation.

Jenny: Are you finding the same thing with the oral version?

Dr. Bergsagel: There’s not enough data. These studies really, in general, they’re done on newly diagnosed patients and they require several years of follow-up. In fact, we don’t even have that much data I think on carfilzomib for that matter. But we believe that that is a class effect, that it probably all proteasome inhibitors have that effect. But there’s not a lot of mature data with the other drugs.

Jenny: I didn’t mean to interrupt what you were saying.

Dr. Bergsagel: So as you delve into this and you try and get, okay, so can we refine this prognostication even further? I guess I’d like to say, we’re not just trying to tell patients, “Okay, you got this, you’re going to do poorly.” We’re saying, “You’ve got this and we’re going to change how we treat you because of it.” We’re going to say, “It’s really important if you have a (4;14) that you get Velcade early than late.” And for patients with deletion 17p, there’s a study from the Netherlands which showed that Velcade maintenance for two years made a big difference for their survival.

So we’ve extended that data a little bit to the patients with (14;16), (14;20), that patients with poor prognosis or worse prognosis we think that it’s important to get Velcade and probably also for maintenance. But the best data for that really is for the (4;14). Sometimes it’s a challenge for some of these things that the (14;16) is about 5% of patients and the (14;20) is maybe 1% or 2% of patients. It’s almost impossible to get really good data with such a small group of patients to know what therapies or what changes the therapies are important for that particular subgroup. And sometimes we just have to extrapolate on things that are similar but obviously not quite the same.

I guess the more recent thing we found out is that the patients with the hyperdiploidy, which is extra copies of chromosomes, those extra copies tend to be — they have three chromosomes instead of a normal pair and it’s called the trisomy. It turns out that it’s really the patients who have got hyperdiploid myeloma, it’s the largest group, probably 40% — or at least 40% of patients and their biology seems to be different. We tend to think that their more indolent, more slow growing. We think that they’re more dependent on the tumor microenvironment.

So what that means in effect is that they actually have more bone disease than patients who haven’t got those translocations because they’re in the bone marrow and they’re stimulated by it. When we take the cells out of patients like that from their bone marrow and we try and study them in a laboratory, they don’t grow very well. It seems like they’re missing some factor or some things that are in the bone marrow that these cells really need. That turns out that it had some consequences.

If you’re diagnosed with smoldering myeloma, which is when you’ve got — you don’t have any symptoms or CRAB features of myeloma, if you’re hyperdiploid, even though that’s a good prognosis where you’ve got multiple myeloma, we recently published that it means that the time in which your smoldering is less. You actually progress more quickly to multiple myeloma. But once you have multiple myeloma, you actually do much better. It’s presumed primarily because of this interaction with the microenvironment, which is somehow feeding the tumor.

But the trisomies appear to be associated with a better prognosis and even when there’s a high risk genetic feature like a 17p deletion or a (14;20) translocation or something else, the prognosis of those patients seems to be more like the prognosis of patients with hyperdiploidy than of patients who don’t have the extra copy of the chromosome. So we think of trisomies in some way ameliorating the prognosis.

Now, that is somewhat controversial. We published that at the Mayo Clinic with our data and the British presented an abstract at ASH where they didn’t see the same thing. So I think it’s probably something that needs to be confirmed — they’ll publish their results so we need to compare and to see if this is a general phenomenon or something that we just saw in the cohort of patients that we examined.

Jenny: And if that’s the case, why do you think that might be true?

Dr. Bergsagel: Well, personally, I think the biology of the hyperdiploid myeloma is I believe it probably may come first and that some of the poor risk features like the deletion 17p and I think maybe sometimes the (14;20), they can sometimes be secondary events that occur later. What really determines or drives the tumor is the primary event in hyperdiploidy, which unfortunately we don’t really know what that is. But that is what shapes the prognosis of the patients and the secondary events have somewhat less influence

But it’s still surprising because deletion 17p which we think is associated primarily with p53 is a powerful prognosis feature at almost every single cancer and it’s hard to see why just having an extra copy of a chromosome would change that. It may turn out that what we found at the Mayo Clinic isn’t reproducible and there was just a chance finding in the patients we examined. So again, I think we need to look at it with some caution and see what the next studies show.

Jenny: Okay. Well, I know translocations then affect genes like MMSET or FGR3 or even BRAF and MEK genes and things like that. I guess the translocations, some of them are specific and then some — I don’t know, like the BRAF and the NRAS and the KRAS that they say a lot of patients have. Do those relate to a specific translocation or they just exist regardless of the translocation?

Dr. Bergsagel: So like the KRAS and the NRAS and the BRAF, those are somatic point mutations that all sort of fall into the same pathway. Generally, they occur regardless of the chromosome translocations. Although in general you can get to specifics, for instance, the translocations are present in MGUS whereas KRAS mutations have not been described in MGUS. NRAS mutations have.

So in general, we tend to think of those class of mutations as being secondary although again there’s not that much data but based on the data that we do have available to us. And if you actually look within certain groups of patients, there can be different distributions of the — so in the (11;14) — and I can’t quite remember which way it goes but there were more KRAS mutations than in other groups.

There can be subtle differences but the number of patients we’ve really studied to look at this is not that great. I mean they are statistically significant, but I think as we get more sequences on more patients that correlate with their genetics we’ll get a better feeling. I’d say in general, those kinds of mutations which as a class, those are probably that’s the most common mutated pathway, we think are secondary.

I guess the other event which is really important, actually a paper that was just published talks about another translocation, which turns out to actually be the most common translocation in multiple myeloma which is with MYC. It’s an amazing story. The MYC translocation was one of the first translocations ever found in cancer. It was back in 1982. And they found that in a lymphoma called Burkitt’s lymphoma and they actually found it in a mouse a myeloma tumor which was called a mouse plasmacytoma. Back in 1982, everyone was excited by this and we thought, well, MYC causes mouse myeloma. Likely, it’s going to cause human myeloma too.

So they looked at this really hard but they didn’t find very many MYC translocations back then. There was maybe 5% of newly diagnosed patients. But we’ve sort of gone back with new genomic techniques using next generation sequencing, and here we’re doing sequencing not to look for single point mutations, but we’re doing sequencing to look for chromosome translocations, which is different. It’s like a structural variation. So it’s a very specific kind of sequencing. And when we did that, we found in fact that all these patients had MYC translocations and we couldn’t pick them up before.

So we studied a cohort of patients from the Multiple Myeloma Research Consortium and altogether 48% of the patients we examined had MYC translocations. So it’s actually the most common mutation in myeloma. It was 43% of the untreated patients and 52% of the patients who had previously been treated. And if we even delved into the details, if we looked at the hyperdiploid patients and the patients who really had the most extra copies of chromosomes, it went up to 70% of those patients. So that’s by far — that’s really the only focal genetic lesion that’s been identified in hyperdiploid myeloma.

There’s not a lot of data but based on the data we have, we don’t think these MYC rearrangements are present in MGUS. We did an experiment in the mouse. We have a mouse in which we put the MYC transgene in to a strain of mouse that’s spontaneously gets monoclonal gammopathy of undetermined significance, so MGUS. We put the MYC transgene into that strain of mouse. All of the mice developed multiple myeloma. But we put the exact same MYC transgene into a strain of mouse that doesn’t get monoclonal gammopathy of undetermined significance and they don’t get multiple myeloma.

So based on that mouse experiment, basically we proved in the mouse that MYC can transform MGUS to myeloma, and we think that’s what’s happening in patients as well that someone has MGUS and then they get a MYC rearrangement mutation translocation and that’s one thing that can cause the progression to multiple myeloma. So that’s a hypothesis that we need to prove, but that’s what we think is happening.

I guess sort of a corollary to that is that when we take a patient and we treat them with the most effective therapy we have and sometimes of course we get a complete response but sometimes we don’t get a complete response. There can still be a small spike present. It might just be a partial response or a very good partial response, but they do — typically, this is after transplant — they do very well for a number of years before the disease comes back again.

At least my hypothesis this time is that those patients at least in those — the tumor was caused by a MYC translocation that we’ve actually got rid of that MYC translocation or the clone that had the MYC translocation and that was left behind is really the MGUS that the patient had to begin with and with time that clone eventually comes back.

So we’re basically planning studies to examine using sequencing approaches to look to see if that’s really what’s happening. What the sort of the importance for that is obviously if we can get a complete response in everybody, we would love to do that. But really what I think maybe our goal of therapy is to get rid of the malignant myeloma cell which at least sometimes is characterized by the MYC translocation I think. And if we can identify that and measure that, that should be the marker that we use to see if we’ve achieved our goal or not.

Jenny: And sort of maybe detecting, trying to find any kind of related cells. Let me ask about this myc translocation. Is it associated with a certain number? Like you hear the (14;20) or the (4;14). Does it have a number?

Dr. Bergsagel: So I told you, it’s like 70% of the hyperdiploid patients, so that’s the most common group. So obviously, it’s associated with trisomies or hyperdiploidy. It’s least associated with the (11;14). It was only about 15% of the (11;14) so there’s a big difference. And then the other translocations are in between those two numbers around 40% to 50%. But fairly associated with hyperdiploid myeloma, less frequent with (11;14) myeloma.

I guess the other thing that’s kind of interesting is that recently we’ve identified drugs that may specifically target MYC. This is actually brilliant work from James Bradner at the Dana-Farber Cancer Institute that he identified a class of drug that inhibits MYC transcription. We’ve shown with him that they’re very active in this mouse model of myeloma and a number of different companies have come forward with drugs based on what he did and they’re entering clinical trials. So it’s very exciting to see if we can really go after what I think is the event that causes the progression to malignant multiple myeloma.

Jenny: And what test is picking up MYC when you’re testing for it?

Dr. Bergsagel: Well, as I told you, we weren’t picking it up before. So there isn’t a really good clinical test right now to pick up MYC. So we’re working to develop that. The problem is we typically have done FISH like we do for the other translocations and we’ve done FISH with MYC and with the genome chromosome 14 which is the immunoglobulin heavy chain. But that’s only about a third of the MYC rearrangements and sort of like that.

A lot of the other myc rearrangements are complex. They tend to be different and they all have a common feature though which is they take myc and they juxtapose it to a powerful enhancer that can dysregulate the expression of the myc oncogene. They’re sort of the unifying feature. The way that we’re looking to pick up is to use sequencing approaches to pick up the rearrangements. And I think that’s probably going to be the way that it will need to be done because they’re really quite different.

Jenny: Last week we talked to Dr. Jens Lohr a little bit about whole genome sequencing and whole exome sequencing. Can you tell us how you’re using those tests in your clinic and in your lab? Are you using them in the clinic yet or this is just research, right?

Dr. Bergsagel: This is just research. I haven’t done as much work with the whole exome — I haven’t done any work like Dr. Lohr has done. And my colleague here, Dr. Stewart, however has developed a panel of about 50 genes that are among the most commonly mutated genes based on the work primarily that Dr. Lohr has done. He developed a more focused assay just looking at those 50 genes to rapidly look to see what mutations are present at a given time in a patient with multiple myeloma. He’s doing it at a very high depth so that he can also look for the presence of different clones which might be present or a mutation might be present only in a particular subclone of a patient.

But my feeling is that there’s really only a few mutations that are, say, present in more than 10% of patients which are the ones that we talked about as well as some that we don’t understand quite so well like DIS3 and FAM46C. I think those new findings, which are really important, are going to lead to biologic studies to understand what those genes are doing and what the mutations are doing. But then clinically what’s going to need to be done is to — sort of the large correlative studies like we’ve done with the chromosome translocations – correlate patients do when they’re treated with different drugs and to look back to figure the prognostic significance.

So clinically, they’re not the kind of mutations that we can say, “Oh, you’ve got that mutation. We should treat you with this drug.” We’re not there yet. I don’t think it’s a clinical test there. And I think I guess to some extent I’m a little bit disappointed by the whole exome sequencing because I was hoping that there’s — so there’s this group of patients that we don’t understand very well, the patients with hyperdiploidy – I was hoping that we might find some gene with a single point mutation that we had missed and that would have explained that. I found that it was a bit disappointing that we didn’t find like a smoking gun and some subtype of the disease. But we definitely got clues from these mutations of things that we need to study in the laboratory.

I think in terms of guiding therapy, it seems to me in myeloma that the genetics are primarily the genetics not of single activating or inactivating point mutations but of gene dysregulation, of juxtaposing oncogenes to enhancers. The reason that is, is myeloma is a tumor of cells that are basically antibody factories and they really devote so much of their time and energy to making antibodies that show up in the serum as the monoclonal protein that we study. What drives that high level are enhancers that enhance gene transcription and they’re misdirected from the antibody genes to oncogenes or cancer causing genes. So it’s sort of that basic biology I think that we need to target.

What that can mean really is targeting enhancers like we’re trying to do, the drug from James Bradner, but also targeting what does it mean to be a plasma cell. I think to some extent that’s what we’re doing with the drug Velcade, which is a proteasome inhibitor and cells that devote so much time to secreting so much protein actually they’re under what’s called endoplastic reticulum stress. It stresses the cell out to make so much protein. A drug like Velcade can really capitalize on that stress. By inhibiting the protein breakdown to kind of overload the cell and cause it to die.

So to some extent, you’re targeting what does it mean to be a plasma cell? I think other drugs that would be like that that sort of target the basic biology of plasma cells are likely to be powerful drugs that will really help a lot of patients. Basically, what that says is — at one point I was sort of looking, oh, let’s find the mutation and let’s find the drug to treat it and sort of seeing the heterogeneity of multiple myeloma and sort of a lack in general of major driving mutations the idea of coming back to less genetically targeted therapy and sort of more biologically targeted therapy targeting the biology of plasma cells I think could be important.

Jenny: So if Velcade is targeting some of the plasma cells and there are drugs that can affect the bone marrow environment, can I go back a minute and ask you if the MYC translocation affects the bone marrow environment or is that more related to plasma cell function

Dr. Bergsagel: So the MYC translocation is really — I think MYC could well have been the very first oncogene that was identified. It was Harold Varmus got a Nobel Prize for it I think in ’73. He isolated it from chickens. So it’s been studied for a really long time. The main thing that the MYC oncogene is thought to do is to amplify the effects of the environment it’s in. It also has effects on metabolism. By amplifying the effects in many tumors that leads to a lot of high level of proliferation, so in Burkitt’s lymphoma is one of the most highly proliferative tumors.

Now, in multiple myeloma, it doesn’t seem to be driving a lot of proliferation. Myeloma is not a very proliferative tumor in general. A patient with myeloma only about 1% or 2% of the myeloma cells are proliferating at a given time. So we tend to think that what MYC is doing is it may be amplifying effects on metabolism or effects on protein translation which are critical for myeloma cells and it’s an area that — there’s a lot of focus on trying to understand that.

We don’t know that MYC per se does anything to how the myeloma cell acts within the microenvironment, to get at your question.

Jenny: And maybe it’s a combination of things. I know you were doing some research on the growth factor. Maybe MYC is doing something to affect something and then the growth factor kind of kicks it into high gear.

Dr. Bergsagel: Yeah. Like the fibroblast growth factor receptor 3 (FGFR3) in patients with the (4;14) can clearly deliver a strong signal that sometimes patients with those tumors — the tumor depends on that. Although it appears like with that one in particular, the tumors can also lose it with time. So it may not be the best target for therapy. But the other oncogenes in the patients with (4;14) is MMSET and that is a gene which modifies the chromatin of the cells, sort of the — it’s what’s called the epigenome but its non-genetic modifications that determine this sort of sulfate. Maybe it’s best to think of it as the sulfate-determining gene

But what’s interesting is that it’s an enzyme and enzymes can be targeted. That is a specific function which is it’s a methyltranferase. So people are trying to develop very specific inhibitors of the methyltransferase function of MMSET and to see if that will have an effect on reverting the tumor. Jonathan Licht, who spent a lot of time studying this, has evidence that if you inhibit the enzymatic activity of MMSET that at least cell lines die. So there’s a lot of promise in that that eventually this could be sort of the magic bullet for that subtype of multiple myeloma.

There are companies working to develop those specific inhibitors, but I don’t think any of them are near clinical trials at this point.

Jenny: Okay. Can we go back for a minute also and talk about the difference between primary and secondary events in myeloma? Can you describe how that works?

Dr. Bergsagel: Sure. So multiple myeloma is a tumor of plasma cells that make an antibody that is often IgG or IgA but it’s almost never IgM. What’s significant about that is that when you get an infection and you have a primary immune response, the very first thing your body does is it makes IgM which is — but when you get a booster and you want to have long lived immunity to whatever it is that you’re responding to, the body takes the antibody from the primary immune response and it switches from IgM to IgG or IgA.

That switch that occurs is actually a genetic switch. It actually involves breaking DNA, deleting some and then rejoining it. And that happens all the time, every time you get a booster shot or secondary immune response. And with all that going on, sometimes the cell makes a mistake and it breaks the DNA but it rejoins the wrong two pieces of DNA during the switching process. So this tends to be obviously an early event in plasma cell biology and that error that it makes basically is the chromosome translocation.

So those chromosome translocations are occurring into the switch region and very early event and they seem to be the primary event that leads the development of multiple myeloma and they’re present in MGUS and they’re present in every cell with multiple myeloma in a patient -every plasma cell in a patient with multiple myeloma.

Now, that basically we think often that may just cause MGUS. Something else is required and that lead to the development to multiple myeloma. The additional things that are required, we call them secondary. So one of them that I described was MYC. The thing about the secondary translocations is that you can target — or the secondary events, secondary mutations is that if they occur quite late, let’s say they occur maybe even the patient already has multiple myeloma, you can target them but it doesn’t really matter because the patient has other myeloma cells that don’t have that mutation

So if you get very late secondary events, you could target them, you get a short-lived antitumor response but there are so many other cells that don’t have any mutation that it just won’t last very long and you’ll just select for the cells that don’t have the mutation. Whereas, if it’s an early secondary event and I would say at least sometimes MYC is an early secondary event, then when you target it you may get them back to the MGUS-like stage, which will be a good therapeutic outcome.

So often we don’t want to target secondary events because we think that — let’s take RAS mutation, for instance, in that paper by Lohr he showed that it’s not infrequent for the same patient to have more than one — they can have a KRAS mutation and an NRAS mutation at the same time. Now what we think that means really is that there are different clones in that patient — some of them with the KRAS; some of them with the NRAS. I think also BRAF was the same thing. So you target BRAF in that patients and the NRAS clone is going to grow up. So it can be discouraging to go after secondary mutations.

Jenny: Now, I have a question about the primary and secondary. So if someone does a FISH test and a translocation does not show up on that but then they do a gene expression profile and it shows off on that, does that mean it might be a secondary or the FISH test may not have tested for what you’re looking for?

Dr. Bergsagel: Well, I have greater confidence in the gene expression than in the FISH. The reason is that when you look at the anatomy of the translocations, there are technical reasons why the FISH may not work based on the kind of probes that we’re using. The other thing is that not always the immunoglobulin heavy chain which dysregulates the expression. It can be the light chain, the kappa and lambda light chain. So frequently the lambda light chain enhancer can dysregulate some of these genes. So that’s particularly true for the 11q13 and the 16q23 so the CYCLIN-D1 or the cMAF or the MAFB. Those are not infrequently dysregulated by a light chain translocation, which we’re not looking for clinically.

So I think the gene expression really looks at the functional consequence of these things, and it’s more comprehensive.

Jenny: Now, on secondary, if you’re looking at causes of myeloma like what triggers it to start moving from MGUS to myeloma or smoldering to myeloma, can viruses do that? As  secondary events.

Dr. Bergsagel: You know, we don’t think of myeloma typically being antigenically responsive which is kind of what you are arguing. The tumor cell or the myeloma cell has sort of lost its control I think from the environment. It doesn’t have the antibody receptors on a surface like a B cell does. And so the viruses, however, can affect the immune system of a patient and it may be that the immune activation that occurs associated with the virus can be associated with myeloma.

One thing that was mentioned was shingles. Patients often present with myeloma with shingles. It may just be that obviously they have immune suppression having myeloma and so they’re more likely to get shingles. I don’t think it’s very likely that the shingles cause the myeloma but it could. It could be the immune activation or the immune environment changes are associated with that.

I do have a patient with multiple myeloma who had a relatively large plasmacytoma in her sternum, about 3 centimeters. She was getting worse and I was all set to treat her when she got shingles, and I postponed the treatment for a little bit. Then when she came back, the plasmacytoma had gone away and her M spike had gone down. She’d had, in this case, the opposite effect. I presume an immune reaction to the shingles also reacted to her myeloma and her myeloma stayed away for about a year before it required treatment. So there can be complex effects of viruses and the immune system on the myeloma.

Jenny: And I know that shingles is part of the chicken pox family so have there been any studies -(and it’s my personal theory, my doctors can’t validate this or they say they can’t validate it. But I had fifths disease which I thought was a triggering event during a pregnancy) so I’m just curious to see if you’ve done any other study in that whole measles, mumps, rubella, chicken pox to see if those are related at all.

Dr. Bergsagel: Herpes viruses were studied and there was a time when people thought that Kaposi’s sarcoma, a herpes virus, also called HHV8, was associated with myeloma but subsequent studies that did not find that. I don’t know anyone who’s looked at other classes of viruses the way you’re suggesting. But I think one of the exciting things of the next generation sequencing will be looking for other sequences from viruses in the data that we’re obtaining and in those cases where whole genome sequencing is performed.

That’s a difficult task. Generally, the way sequencing works is you only find what you already know about beforehand and trying to find — so the sequences that have been done can be searched for rubella and all those different viruses. As far as I know, there’s about 23 whole genomes published by the MMRC which are available. But I don’t actually know if anyone has done that yet. I think the techniques for doing that are complicated and I think people are developing them. There haven’t been that many whole genomes performed. But if there is a virus in the tumor cell, then eventually it will be found using techniques like that.

Jenny: This next generation sequencing, so that’s not the whole genome and exome sequencing? That’s something else?

Dr. Bergsagel: That’s a whole genome. To find the virus, that would be a whole genome approach.

Jenny: Okay. I know that many, many new approaches are trying to approach different things like the HDAC inhibitors and the PI3K inhibitors. How do you find these types of new approaches?

Dr. Bergsagel: Well, I think that they’re promising — one reason I think that is — I mentioned we have this mouse that develops multiple myeloma and what’s nice about that mouse is that it behaves very much like patients with multiple myeloma and we can treat different mice with different drugs and see how they respond. We do the exact same thing we do with patients. We measure the M spike before treatment and after treatment. We’ve actually determined using this mouse that if a drug works in our mouse, 68% of the time when it’s been given to patients in a clinical trial, the same drug has also worked. On the other hand, if we treat the mice with the drug and it doesn’t work, then 90% of the time the clinical trials didn’t work in patients.

So it appears to be highly predictive of what the drugs will do when they’re given in clinical trials to patients. In the treatment of these mice, the HDAC inhibitors, in particular, are really quite active on their own but very active when they use the same combination with Velcade, which is the way that they have been evaluated in clinical trials.

Unfortunately, one clinical trial that was published which looked at Vorinostat and Velcade and it didn’t really seem that much better than Velcade alone. However, there’s another clinical trial that I think presented ASCO in June this year, which looks at the combination of another HDAC inhibitor called Panobinostat with Velcade. The company had reported that they met their endpoints suggesting that there may be an important clinical benefit to that. So we’ll see when that comes out.

So I think the histone deacetylase is relatively a broad class and it may be that we’re getting a signal with these first generation drugs, but if we can more precisely identify which is the critical target to inhibit within that class we may be able to hone down in and get sort of more effective therapies.

Now, the PI3 kinase inhibitors are slightly different because they’re more into the signaling inside a cell, and I would include in that class Akt inhibitors and PIM kinase inhibitors which are signal transduction kinase inhibitors sort of similar or overlapping pathways. The PIM kinase inhibitor there’s been one from Novartis which is entered Phase I trials in which they’ve seen evidence of single agent activity that they reported on. It may be that that’s a clue that really these drugs which have been shown in preclinical studies by many investigators to be active but that they may also be active in patients. The clue I think will be to find the right ones and perhaps the right combinations that will be specific without a lot of side effects

So I think that there’s promise there. I think it may take some work.

Jenny: We’re going to need people like you to say, “Okay, you need one of these and two of these and three of these for the type of myeloma that you have.”

Dr. Bergsagel: As we’re talking about drugs, I wanted to — there’s been a problem I think in prioritizing drugs for clinical trials in myeloma because a lot of it has been based on the fact that they’re very active in myeloma cell lines which we have in our laboratories that grow very rapidly in culture. They may work in immunodeficient mice models that are commonly used. But a number of those drugs have been taken forward in the clinical trials and really most of them haven’t worked. Really trying to know ahead of time if a drug is going to work or not and a patient in clinical trials has been a real problem for us which is one reason why we’re excited about the fact that our mouse model seems to be predictive.

Recently, we took a drug that honestly I didn’t think was going to work and it’s called an Inhibitor of Apoptosis Protein. It’s a class of drug which we abbreviate as IAP antagonist. The one in particular is called LCL161. But in many ways what this drug does is it mimics a mutation that occurs in some patients with multiple myeloma that activates the NF-kappa B pathway. It’s sort of an important pathway in myeloma and there’s actually many different mutations that fall within that pathway. This drug  mimics the effects of one of them.

So you would predict that if you give a tumor the mutation that it normally gets that you would make the tumor worse, that you would cause it to grow more or to spread outside the marrow or something. And so when we treated the mice with it, that’s one thing we were looking for is if we give this drug to myeloma, does it make them worse? We were kind of surprised to find that when we did that, the tumor actually went away complete

In our mouse model it was really the most active drug. It’s active as Velcade or melphalan. The tumor stayed away for a very long time. But we were puzzled by this because it didn’t really make sense to us. We treated cell lines in vitro with the drug. They weren’t killed and we treated tumor cells from patients with what we think are physiologic concentrations of the drug and they weren’t killed.

So it wasn’t really until we did some more studies in the mouse where we found that we don’t think the drug is actually acting on the tumor cell. We think it’s acting on the immune cells in the mouse because the NF-kappa B pathway is really an important pathway for immune cells and primarily, in this case, we’re talking about what’s called the alternative NF-kappa B pathway which is important for innate immune cells.

This drug is relatively specific for activating that pathway. If we take the exact same tumor cells and we put them into a mouse with a mature immune system, the drug works excellent, very well. If we put the exact same tumor cells into very young immature mouse — doesn’t have a mature immune at all but otherwise it’s a normal mouse, it’s just very young and then we treat it with the drug, the drug doesn’t work at all.

So it can’t be a direct antitumor effect or it would work in the young mice just like it does in the old mice. By looking into it, we also did some studies where we combined this drug with Velcade or we combine this drug with dexamethasone. And both times the drug didn’t work as well. Those drugs inhibited the effect of this drug. Of course, one characteristic of both those drugs is that they suppress the immune system. So we think they’re suppressing this immune effect.

This drug has actually been given to a number of 200 patients I think with solid tumors in Phase I and some early Phase II clinical trials and in other cancers. It’s a pill that’s very safe. What happened to those patients when they took it is that when they got up to what was the dose limiting toxicity at quite high doses was what’s called the cytokine release syndrome. Cytokines are basically kind of like hormones that come from immune cells that really stimulate the immune system.

So these patients were having this very massive immune stimulation occurring in about three or four hours after they took the pills but when they backed down the doses either they didn’t see it so much. And they showed, in fact, in the patients that there’s — one of them is called Interleukin 8 and that’s a cytokine that attracts neutrophils, which are one of the most common white blood cells but they’re an effector cell which, when activated, can kill tumors. This cytokine went up a hundredfold in the serum of patients after taking this.

I think for multiple myeloma, there’s a critical relationship between the myeloma cell and the innate immune cells that support its growth in the bone marrow microenvironment and that when you give this drug, the Interleukin 8 is secreted and all the innate immune cells go to wherever — all the neutrophils go to where those cells were, which in the case of myeloma is right around the tumor in the bone marrow.

So we’ve started a clinical trial at the Mayo Clinic with this. I can say it’s tolerated just like it is in patients with breast cancer. We’ve seen early evidence of efficacy. It seems to be a really nice therapy. We have evidence in the mouse that even though drugs like Velcade and dexamethasone inhibit its effect in a mouse when we combine it with cyclophosphamide, we see a very dramatic enhancement of activity. We’ve seen the same thing that the clinical trial is written that if a patient progresses on the LCL161 alone that cyclophosphamide is added, and we’ve seen the same kind of synergy in the patients on the clinical trial. So it looks to be very promising.

Jenny: This is a Phase I trial?

Dr. Bergsagel: No, it’s a Phase II. We’ve gone with the dose that was used in the solid tumors.

Jenny: And then are you using it by itself or with cyclophosphamide?

Dr. Bergsagel: The way the study is written is it’s LCL161 alone and if the patient happens to progress, then cyclophosphamide is added on.

Jenny: Wow! Well, that sounds really exciting.

Dr. Bergsagel: To think that you can take a pill once a week that boosts your immune system – in general the patients feel better and we’re seeing quite dramatic responses. It’s promising. There are very few patients on the trial so far so everything is very early. Really what we can say is it’s tolerated very well like it is in the solid tumors.

Jenny: Well, I’m just wondering if myeloma might — I don’t know what your opinion is on why myeloma relapses and why it comes back more aggressively. But if an immune compromised situation and you have a way to boost your immune system, maybe you would prevent relapse.

Dr. Bergsagel: So we’ve kind of done studies like that in a mouse. That’s the great thing about having a mouse model that’s immunocompetent. So I told you, if we treat with this drug for a couple of weeks, the tumor goes away completely, even stays away for months, which is good although it makes it kind of hard for us to do studies. But then we’ve taken some of those mice and we’ve got some mice where it’s stayed away for a year. I mean just basically two weeks of treatment and they stayed for a year. And then we’ve challenged them again with the tumor. The tumor doesn’t engraft. So what that tells you at least — there’s only one mouse. But in that mouse, it would appear that it developed an immune response that allowed it to reject the tumor.

It may be that if we did that with Velcade or melphalan we would find the same — we haven’t done that study with other drugs so I don’t know – maybe any mouse where the tumor stays away for a year, it had developed an immune response for that to happen. It’s a bit selective but obviously it’s better if you’re giving drugs that boost the immune system as opposed to ones that suppress it.

Jenny: Yeah. Well, absolutely. Now, I want to leave time for caller questions and I will. But I want to ask you where you see your research going next and if you have other trials you’d like to talk about before we open that up.

Dr. Bergsagel: Sure. My research really is focused in two main areas. One is MYC, which I talked about before because, as I said, it’s the most common mutation in myeloma and there’s some ways that target it. But I really want to understand what does it mean to a patient and should MYC really be the target of therapy and can we get rid of it. So I’ll be opening up a Phase I clinical trial of a bromodomain inhibitor. It’s the class of drug that James Bradner identified here at the Mayo Clinic, and I’ll be looking to correlate what happens to the patients with what kind of MYC rearrangements they have and developing a clinical way that everyone can identify the MYC rearrangements.

And then the other one is primarily being led by Dr. Marta Chesi who works here with me which is to look at the immune control of multiple myeloma. Here it appears that our mouse model has given us a really valuable tool where we’ve got the whole immune system, the microenvironment, the myeloma in the right place. There are so many manipulations that can be done when you’ve got a mouse model that has those features.

 

There’s other drugs which can modulate the immune system besides LCL161. There’s a class of drugs which are called checkpoint inhibitors – PD-1 which are entering clinical trials in patients, and we’d like to use them in this mouse model to see what really is the best way to use them. We have some preliminary evidence that the mice do respond to this kind of immune modulation. So I would say studying the immune microenvironment and studying MYC is where I’d like to go with my research.

Jenny: What’s the impact of patients participating in clinical trials for your research?

Dr. Bergsagel: Oh, it’s absolutely critical. Whenever I’m talking to a patient, I always strongly encourage them to participate in the research clinical trials as their first choice. If there’s some reason that they can’t, then, of course, then we’ll do something else. Advancing the science and learning more will help everybody. Not infrequently they’ll have access to exciting new drugs really before they’re generally available which I think can be an advantage.

Jenny: Well, thank you so much. We’d like to open it up for other questions.

Dr. Bergsagel: I guess I’ll just add one more thing. The clinical trial I mentioned with the LCL161 is available at all three Mayo Clinic sites. So it’s open at the Mayo Clinic in Jacksonville, the Mayo Clinic in Rochester as well as the Mayo Clinic in Arizona.

Jenny: And how many patients are you working to accrue for that?

Dr. Bergsagel: That’s a small Phase II clinical trial so I was looking to get 27 patients as it’s currently written. We’ve got six so far.

Jenny: Okay. I would encourage patients to join that trial so you can find out. I think that’s fantastic. We’d like to open it up for caller questions. So if you have a question for Dr. Bergsagel, please call 347-637-2631 and press 1 on your keypad.

Okay, so we have our first caller. Go ahead.

Caller: Hi. Can you hear me?

Jenny: Yes, we can hear you.

Caller: Thank you. So I wanted to go back to some things you said towards the beginning of the interview, Dr. Bergsagel, about the well-known fact that certain genetic anomalies detectable on FISH have poor prognosis. And I wanted to ask about that in the context of the heterogeneity of the disease – the fact that a patient may have multiple clones in a tumor, and I want to understand whether the presence of these anomalies in a small percentage of the plasma cells is significant compared with having it in a large percentage of them.

Dr. Bergsagel: That’s an excellent question. As I mentioned before, the translocations tend to be in every single cell, so the (4;14) and the (14;16) and the (14;20), for instance. So they’re not usually subject to heterogeneity. The one that really is though is the 17p deletion. And there the French have shown that if it’s a minor proportion of the cells, it did not seem to be prognostically important. I think they’re cut off — I can’t remember if it was 30% or 60%.

Caller: I read that paper and it was 60%. They broke the population into those who had zero to 30, 30 to 60 and more than 60. And only in the last category did they find prognostic significance.

Dr. Bergsagel: Right. I would tend to think that, let’s say you’re in the 30 to 60 group that it may have prognostic significance but they couldn’t detect it in their study that maybe over the long term. So it’s not nearly as bad. But I guess I’m a little bit afraid of therapy but when you’ve got clonal heterogeneity like that that a therapy will wipe out the most sensitive cells and enrich, in a way, then for the ones that are resistant. When they come back they’ll have — you may be 30 to 60 initially but when you come back the next time, you’ll be over 60. So I think it would be nice to kind of think that you could monitor and see what happens over time.

Caller: And how would you go about monitoring this?

Dr. Bergsagel: That would be FISH. You have to get — the FISH labs are usually very good about telling you how many cells are abnormal, but they’re not always as good about honing in on the myeloma cells. So when you take a bone marrow, often the sample that goes to FISH might have 5% or 10% myeloma cells in it then 90% other cells. There’s various technical reasons why this occurs but it often can be dilute for tumor cells. If you’re not focused in only on the myeloma cells, you might not see what you’re looking for and certainly not the heterogeneity.

So there’s a couple ways you can focus in only on the myeloma cells. One is to select them before you do the FISH with something called CD138, and the other one is when you do the FISH to stain for immunoglobulin like kappa or lambda light chain and only look at the nuclei of the cells that have immunoglobulin. And then you can I think get a much better feeling for heterogeneity.

So the French study that you’re referring to, they did the CD138 selection first and then they did the FISH.

Caller: Oh, I see. Okay. But to monitor the changes in a given patient would require sequential bone marrow biopsies to get this data, right?

Dr. Bergsagel: It would. I’d often try and get a bone marrow when a patient has relapsed and they’re going to start on a new therapy, I typically would get a bone marrow at that point and try and see what’s going on. But I do have to emphasize that if you had FISH done and they didn’t do CD138 selection or they didn’t do the cytoplasmic staining, then seeing 60% or 30% 17p doesn’t tell you anything. You really need to only count the myeloma cells when you do that. A lot of laboratories don’t enrich for the plasma cells. So you can’t interpret the percent staining

Caller: Yes. Just to tell you my personal case, my wife is the patient and she has had a couple of bone marrow biopsies and where the FISH was done at different lapse and one did select plasma cell with CD138. The other did not. There’s quite a difference in the results.

Dr. Bergsagel: Yeah. That’s what I would expect.

Caller: Okay. Thank you very much.

Dr. Bergsagel: You’re welcome.

Jenny: We have another caller. Go ahead with your question.

Caller: Hi. Just a quick question on the study that you’re doing. At what stage does a patient need to be to participate in that study?

Dr. Bergsagel: That’s an excellent question. So for that study, the patient has to have had been treated at some point in the past with Velcade or with a proteasome inhibitor and at some point in the past with an iMiD so Revlimid, thalidomide, pomalidomide. And the patient has to have less than five previous lines of therapy where a line of therapy is induction, transplant, consolidation and maintenance will be considered one line of therapy. They have to have had less than five lines of therapy.

Caller: Okay. Thank you.

Dr. Bergsagel: You’re welcome.

Jenny: And we had one email question from Heidi who says, “What is the impact or recommendations if you have more than one bad prognostic indicator like you have (14;16) and deletion 17 and deletion 13? In your genetic research, what do you suggest?”

Dr. Bergsagel: So I guess one thing, I didn’t talk about deletion 13 because we don’t use that as much. When it’s detected by FISH, it’s present in almost half of the patients and by itself is not independent of the other things I have talked about. So like deletion 13 in hyperdiploidy doesn’t carry a bad prognosis. So FISH deletion 13 is not very significant.

What is significant is sometimes we get a metaphase karyotype where the cell is divided in vitro and we can stain the chromosomes. And there, if you see loss of a chromosome 13, that does carry prognostic significance. So you need to distinguish the method which is done usually in FISH. But then to get to your question, if you got both (4;14) and 17p, then that’s worse than having either one by itself.

Jenny: Okay. Well, great. Well, Dr. Bergsagel, thank you so much for joining us today. You’re doing really amazing work. Thank you for digging deep into this disease to find new and better therapies for us all. We’re so very grateful that people like you are working to help find a cure for us.

Dr. Bergsagel: Great. Thank you very much. It was my pleasure.

Thank you for listening to another episode of Innovation in Myeloma. Join us next week for our next mPatient Radio interview as we learn more about how we as patients can help drive cure for myeloma.

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