From Lab to Life: Expanding the Power of CAR T Cells

[00:00:00]Welcome to the Science at uh podcast sponsored by the University Hospitals Research and Education Institute where we explore breakthrough research, clinical innovations, and the science of transforming patient care and health outcomes. I'm your host, Dr. Dan Simon.

[00:00:21]Thank you for listening to another episode. Today, I am happy to be joined by two guests, Dr. David Wald and Dr. Rashmi Parmaswarn.

[00:00:32]Dr. Wald is the John Chrisman and Francis Drake Professor of Pathology at Case Western Reserve University School of Medicine, the co-director of the immune oncology program in the case comprehensive cancer center and the director of hystocompatibility and immunogenics lab at University Hospitals Cleveland Medical Center.

[00:00:54]Rashmi Pararmasaran is the director of cancer biology training program at Case Western Reserve University. She is she is an associate professor of medicine in the department of medicine at Case Western Reserve University. Welcome.

[00:01:10]>> Thank you.

[00:01:10]>> Thank you.

[00:01:12]>> Well, it's great to have you here today.

[00:01:14]These are really two of the gems of of research um in the Sidman cancer center at University Hospital Sidman cancer center and at Case Western and we are going to learn a lot for them today um about CARTT therapy. But before we start there, you know, it's always great for us to learn a little bit about each of you um where you're from, how you got here, and your journey. And um Rashmi perhaps we can start with you because it's so interesting that I noticed that you went from India to Israel. So tell us a little bit about your background.

[00:01:52]>> Sure absolutely. So first of all thank you for inviting me to this podcast and my journey is from east to west and started in India in a small state called uh Kerala and I did until master's in biochemistry there and then moved to Israel for PhD at wiseman instead of science um at wiseman actually I got introduced to cell therapy and I was fortunate to work with uh many of the eminent scientists there including Dr. Seligar who is the inventor of Karti and who is the father of Karti and we all students were motivated by that discovery and from there I moved to Los Angeles for my post-docctoral fellowship in children's hospital Los Angeles and there I was working on a protein called BAF bell activating factor and uh the receptors of BAF actually works um actually it's expressed on almost all B cells normal B cells as well as cancer B cells and also autoimmune B cells. So I was thinking of uh like targeting these receptors will be a real uh attractive strategy for treating many of the diseases and when I moved to Case Western as a faculty and started my own independent lab in 2016 uh I was thinking of making a car with targeting baff receptors and that's when I met Dr. Seligar in a conference in Melbourne and I was discussing with him about this idea and I told him see I don't have antibbody sequences for these uh receptors because for a conventional car approach you need uh antibbody sequences and I think like me most of the PIs who want to target many proteins or antigens uh they don't have access to these antibbody sequences so then I thought about what about using a natural again in a car because the whole idea is cancer cells should come and bind to cartis cells and cartis cells should attack them. So it's all about binding.

[00:03:57]So I thought why not I use a natural liant or ext extracellular sequence of a liand and I discussed with this drashar and he said why not you just try then only you will know. So then we started trying and of course that worked very well in all the preclinical bell cancer models and right now it's in four clinical trials for three different cancers and for autoimmune lupus. So here I am with uh you know now my lab is focusing on cancer imunotherapy strategies carti and carn for solid cancers as well as autoimmune diseases.

[00:04:33]David, a little bit about um how you got to where you are today.

[00:04:38]>> Sure. First, thank you so much for the opportunity to talk about our work today. Excited to to be here. Um so, actually, my kind of journey started in Cleveland. I was born in Cleveland. Um kind of from a very early age, I knew I wanted to discover new therapies and work on, you know, therapeutic development. My grandfather was a pharmacist and I think my passion for that came from interactions with him early on. Um, but I didn't know what that involved or, you know, where that would take me. And then, um, I went to college at Cornell University. And when I left for college, I never in my wildest dreams thought I'd end up back in Cleveland. Um, but then I came back for the MD/PhD program here, did a pathology residency, and I still never thought I would end up in Cleveland, but I am here today and I think it's one of the best decisions I've ever made. Um, I just kind of fell in love with the infrastructure, had such great support from the institution, and I never left.

[00:05:28]When I did my initial research training, I worked in the area of immunology. Um, and then during my clinical rotations, um, I really developed a deep interest in cancer, just seeing cancer patients, um, going through chemotherapy with all the horrible side effects and just seeing as there's so much unmet need for patients with relapse through refractory malignancies. And so the early half of my career was focused on drug development on the small molecular therapeutic side. And actually I have to thank Rushmi partially for my transition into cell therapy because I had the opportunity to work with her when she first came to Cleveland and she was working on NK cell projects and that really opened my eyes to um cell therapy and and since then now my lab has been focused on NK and CAT therapies primarily.

[00:06:08]>> Well, you know, it's it's just uh great to hear about those paths. I mean they're uh very ciruitous, but the great thing is is that we have both of you here. I think for our listeners, you know, many don't realize that Cleveland has a lot of um prominence in cell-based therapies. You know, the misenlal stem cell was discovered by Arie Kaplan of Case Western and Stan Gerson's real drive into cell-based therapies was responsible for us being named the National Center for Regenerative Medicine with tremendous investment both from federal sources as well as state sources and you know we have this amazing cell production facility that allows us to really you know flourish in this space. So, we owe so much, you know, to others as well. Uh, but we're here to talk um uh about two of our stars today. Now, to set the stage for all of this, I think maybe both of you could just comment a little bit. The idea of leveraging our own immune system uh to attack cancer is, you know, very commonly held now. Uh but it always hasn't been that way. We know that cancer is very good at cloaking itself uh from the immune system. But perhaps you could tell us to set the stage for eventually talking about CARTT. How is it that potentially our own body can be leveraged to fight cancer? So maybe uh Rashmi we can start with you.

[00:07:41]>> Yeah sure. So our immune cells always have the capacity to fight with cancer cells and kill cancer cells and mostly two types of lymphocytes play important role like T- cells and NK cells and both of these cells are really good at doing their job but obviously we know people get cancer. Why? Because these cells either become dysfunctional in patients or uh they they cannot do its job because of some other factors around them. Some other proteins surrounding them makes them dysfunctional. So sometimes they cannot do their job to its best and that is where this adaptive cell therapy comes to play. So we have to take uh blood from patients, take the immune cells out like T- cells or NK cells and in car therapy especially we are making them more active and giving them more specificity. So we are telling these immune cells or T- cells especially to go and kill only cancer cells and spare the normal cells. So that's a specificity part and also uh for safety in terms you know it's our own or patients own um immune cells. So safety wise also it's not a big problem.

[00:08:56]So using a patient's own immune cells I think it's very attractive especially in carti field we are giving them specificity as well and also we can expand them xvivo in a large number because in patients they will not have enough number of tea cells. So we can expand these tails cells in millions uh xvivo and then give them large numbers of carti cells. So all these ways I think cartis cells are really promising.

[00:09:23]So David, a little bit from you on a little of the the cancer cloaking properties and how we can at least through drugs as well, PD inhibitors and and and others try to um allow our own cells before we engineer them to do their thing too.

[00:09:43]>> Yeah. So um tumors are are very smart.

[00:09:45]They try to evade the immune system. And that's why, you know, initially they're able to to progress is because they develop strategies to evade the either make them dysfunctional as Russia mentioned or to evade them or block them. And so, for example, um when we infuse te- cells into into patients, um there's one of the initial issues with trafficking into the tumor. So, so tumors create um barriers for the tea cells to even enter into the tumor. They can do this physically. They can create factors that they secrete. One of the dominant factors is called TGFBA beta for example and that causes dysfunction of the immune cells and also um modifies their their trafficking receptors that prevent them from actually entering the tumor. And so you know strategies that people are trying to develop to improve the trafficking um I think is one key element and also once they get into the tumor then tumors have a lot of different strategies by modulating the metabolism um by making that a very hostile environment for the tea cells to maintain the activity and so using factors for example in norolucan 15 cytoines that could boost the activity um of these immune cells can help to overcome that as well.

[00:10:49]>> That's great. So I think you know um we've seen from the days you know when I was um treating cancer patients as a as a resident it was all chemotherapy and of course now imunotherapy makes up at least 40 to 50% of treatment protocols for patients. So it's a it's a complete uh revolution. So all right we've talked about CARTT cells and now we have to get really basic here. What is a CARTT cell?

[00:11:18]How are they manufactured? I know David, you're you're really focused on speeding up that manufacturing process. Take us through what is a CARTT cell, how we make them, and then what is it that you've done to try to speed up this process so we can treat patients in a more timely manner. So, David, why don't you start?

[00:11:39]>> Sure. Um, and so CARTT cells are essentially a genetically engineered TE- cell and so you have to get a starting cell source. um it could actually come from a variety of different um areas. It could be an autotogus product which are all the FDA approved products or autotogus products. For all those products, you start with what's called an apheresis sample. So, it's a large collection of essentially um monuclear um white blood cells. Um there are methods now to use peripheral blood or stem cells um as well if you want to make allergenic or off-the-shelf therapies but essentially you need a source of the tea cells and then you take them into a GMP facility which needs to be a very specialized facility with specific air handling requirements and um procedures to be able to produce this in a sterile fashion that's safe for patients. Um and then you essentially need to introduce the car the chimeriic antigen receptor gene into the T- cell. Most commonly that's done by a lentiviral um vectorbased approach but there's other approaches like electroporation and transposons um lipid nanoparticles and other ways you can introduce that genetic material into the tea cells and then historically um it was thought that you needed large numbers of these cells to see significant efficacy. They were expanded into billions of cells in the lab over a course of one to two weeks and then infused into the patient. And kind of what we've been working on is trying to to shorten that process and trying to prove that you don't actually need as many cells to get um good outcomes.

[00:12:59]>> So you know Rashmi it's very complicated and you already talked about some really interesting tricks that you did as you said to attract the cells by having multiple lians you know uh uh present.

[00:13:13]you know, this is all done in the lab now, but there's this promise potentially that we can do these and make these CARTT cells all in vivo that we won't need to take them out. So that um although you've accelerated the manufacturing, David, to maybe quality control and release in a week as opposed to four to six weeks for commercial products. Um it would be great to be able to make them in the person themselves. So Rashmi tell me a little bit about what's in that space right now.

[00:13:46]>> So uh when we talk about Carti manufacturing like David said he has the ultraast manufacturing which shortens the time of manufacturing as well as the cost but there are other features like we have to consider car designs which uh increases the cart persistence in vivo in patients. So certain designs we already optimized so that it increases the persistence of cartis inside patients as well as we can uh activate uh the cartis cells by using certain designs. So we are in an era of optimizing all these designs and scientists already have done that part.

[00:14:24]So the next era as you said is all about invivocar uh giving them like mRNAs L&PS like nanopolymer particles with mRNAs and then it will just go and infect patients T- cells and all the process we did outside the body will happen inside the body and then that will again shorten the uh weight for especially for terminally ill patients this 3 weeks weight is a lot so that will shorten the weight and also the probably reduce the cost of cartither therapy. So there are other cartither therapies coming. Now we are now in a fourth generation cartis era and fifth generation is going to come. So we have uh many different armored cartis where they use extra cytoine receptors which help their persistence as well and also proliferation.

[00:15:19]And there are recently ant gated cartis where we use two cartis only. So if it binds to two antigens it will work. So that will reduce offtarget effects. So there are so many attractive cartis coming up which all will really help.

[00:15:35]And one of the cartis I mentioned is lian based carti which I developed which is all based on a natural protein sequence which will really help for multi- receptor targeting. So antigen escape is a big problem in the field of cartither therapy. So multi- receptor targeting most probably I assume or I hope it will help uh escape that antigen loss phenomena. It's incredibly exciting when you say we're already in fourth generation, but take us back just a little bit uh David and Rashmi to okay intentionally you went after blood cancers as we call it uh easy accessibility started in lymphas in multiple myyomaas. Tell us why is that an attractive place to start and then what are the challenges on the other side for solid tumors? Uh so why did we start uh with lymphoma in blood in blood cancers?

[00:16:33]>> Well, I think you know the efficacy is significantly higher um clinically and I don't know that we entirely know all the reasons for it but it it just works very well. I have my own um kind of ideas of why it works well for lymphas for example because you have normal B cells.

[00:16:48]The cartis cells are actually killing the normal B cells as well but people surprisingly could survive quite well without normal B cells. In contrast for solid tumors, you know, you don't have the same targets that are very specific to solid tumors in many cases where they're not on at least a subset of normal cells. And typically those can give very high toxicities when you start to see high efficacy. And you really need the you know kind of at least in the B cell context, you need the full elimination of normal B cells to see the strong efficacy. And so I think you know selection of targets has been very challenging with solid tumors. The tumor micro environment is also quite different with solid tumors versus blood cancers. And I think that makes it easier to see efficacy um with blood cancers as compared to solid tumors.

[00:17:30]>> So right now um we use CARTT cells in lymphoma for lymphas that have failed you know standard therapies and you hear stories of patients who've failed four five different regimens who come in and it's their last hope and yet you're able to get them into uh complete remission.

[00:17:53]Are there efforts underway to use CARTT upfront as firstline therapy uh in trials now?

[00:18:01]>> Yes, there is um trials for upfront treatment um getting approvals at lower and lower lines of therapy. Um we're actually in discussions with some oncologists at our center. We really like to do a trial for particularly patients who you know that they're just not going to respond to chemotherapy.

[00:18:15]there's patients with very aggressive, very, you know, poor high-risisk um outcome patients and you're having them treat chemotherapy knowing it's not going to work. Um it's be better to try a CARTT therapy. And so we've been in discussions with some of the oncologists here, maybe we could start something in the future at uh to to specifically look at that in a subset of patients. So Rashmi, how did you migrate to multiple myyoma and then from multiple myyoma to one of the most resistant cancers that you had ever treat which is osteocaroma?

[00:18:47]You know this cancer that affects adolescence and young adults that like pancreatic cancer we've just not seen major advances in our medical lifetimes.

[00:18:57]So how did you go from multiple myyoma to osteocaroma?

[00:19:01]>> Yeah. So that's a good question. I like I told you earlier I worked with a protein called BAFF uh for about 20 years and that receptors of BAF are present on multiple myyoma. So especially BCMA and Tassy two receptors of BAF are present on multiple myoma cells and we can target those two receptors at a time using BAF cardi.

[00:19:24]That is why we started with multiple myoma because CD19 carti which is a FDA approved right now is not good for multiple myoma treatment because multiple myoma cells lack CD19. So that's a good strategy to target two other receptors BCMA and Taci using BAF carti. So that's how we started with multiple myoma. And coming to osteio saroma it's a total different story.

[00:19:48]It's a solid tumor. Lot of challenges waiting there and we were looking for tumor specific markers, tumor specific antigens and uh encoatin M or ISM is one such protein where its receptors are expressed on most of the solid tumor cells. So when we looked at the database we found that osteocaroma cells express actually both of its receptors OSM receptor and lift receptor. So then I thought okay that's a good idea let's take OSM let's make OSM carti first and try to deal with osteio saroma and surprisingly it was really surprising to see in mouse models these osteiocaroma tumors uh were totally like gone like disappeared in a matter of 4 days. So that was really surprising because how these carti cells entered that solid tumor compartment and kill the tumor cells. So that's how we started the study and then we found that very interesting observation that our oam cartis cells can kill cancer associated fibroblast. So the solid tumors have a solid structure which makes it difficult for the cartis to infiltrate into the solid tumor cells. So cancer associated fibroblast gives it a solid structure and our OSM carti actually targets the cancer associated fibroblast because under chronic inflammation or under cancer the o receptors are really upregulated in cancer associated fibroblast as well as in tumor cells. So we are not only targeting tumor cells we are targeting the micro environment as well. So once it kills that fibrolastic structure it can enter and find the way into the tumor cells and kill them. So that's the advantage of uh this cartifi for osteio saroma and that's why we started with osteio saroma because of database showing a good expression of the receptors. I have a question you know so um in at least liquid tumors uh lymphoma tumors you have the circulation the bone marrow lymph nodes there's there's access in solid tumors as you pointed out there are a lot of protective mechanisms but there are issues of getting sufficient number of cells there so that has led to for instance in glyobblasto uh local therapy uh into the ventricles through a pump and things like that. Is there data that you're going to need both systemic and local therapy? Where does that sit right now?

[00:22:27]>> So there were many carti tried for osteio saroma for example B7 H3 carti gfr carti etc. But all of them uh were not big success yet because uh these carti cells has to find its way to the tumor and it has to enter the tumor. So that is the main challenge. That's why I said because our oam carti at least uh kills those fibroblastic solid structure. We are assuming that it will uh find its way to the tumor cells exactly the way it worked in mouse. We are expecting that it will work in human but mouse are mouse and human are human we never know but at least that is the advantage we are seeing for our cartis like targeting that solid structure and finding its way to the tumor. So um you've talked a little bit about NK cells uh which are called natural killer cells for our listeners and there is something called carn what is a carn cell how is it different than a cart cell and where where are using them now so maybe David you could start >> carn are similar to cart cells in terms of that it's you know an nk cell instead of a t- cell but they express chime antigen receptors um and so there has been a lot of work done for example on CD19 CARNK cells there's certain advantages and disadvantages of ENK cells um disadvantages are they don't persist very well in vivo um they don't expand as well and so you see more of a transient effect the advantages are they could be used as universal donor so we've done several trials at at university hospitals using what are called our universal donor offtheshelf NK cells and so it's much cheaper to make they can be accessible any time because they're just frozen they just need to be thought and infused um and so we've done a a bit of work with CARNK cells um for some solid tumor targets in particular. Um in our kind of head-to-head testing of the CARNK versus CARTT, we just see much better efficacy with the CARTT cells. And so I think for cancer therapy now, the field is moving a little bit away from NK cells and more towards T- cells. A lot of autoimmune non-malignant conditions, there's still a lot of efforts in NK cells, but a lot less than there was a few years ago. But I think in the future you know if there's more strategies developed and more mechanisms understood to get better persistence and expansion of NK cells in vivo that could again shift shift very rapidly.

[00:24:50]>> You know it's interesting you you talked about this ability to go to using lower number of cells and have more stemness. So these cells are are persistent and they're surveilling, you know, cancer from coming back is a very interesting thing because it's almost like you you've got someone on your team knocking the cancer down, you know, for years, so to speak. So what is the evidence that CARTT cells are persistent for how long? How long are they there?

[00:25:21]>> Yeah, that's a good question. I think, you know, no one knows for sure, but they have been measured, you know, 10 years out in patients. And so there are, you know, examples where they could potentially persist forever. Um but definitely, you know, months to years is typical um at low levels. Um and then when, you know, the tumor starts to come back, you can actually see in patients that these carti cells are reexpanding again. Um and I think you really need that persistence for the long-term durability. And that's where ENK cells may may actually be used in in in conjunction with CARTT cells. For example, you know, if the patient needs to be very treat treated very quickly, maybe you give a dose of ENK cells to control the disease while the CARTT cells are being prepared and give maybe longer term durability. That's very interesting. So, Rashmi, you mentioned a little bit about autoimmunity and non-cancer indications. So uh my lab happens to also study uh lupus or systemic lupus aithmitosis slee uh affects predominantly women uh and uh can be a devastating uh autoimmune disease that affects you know the kidneys lungs skin uh CNS uh thrombotic complications very exciting data uh in carti and lupus tell us a little bit about that story because I know that you're very interested in autoimmunity as Yes. Uh we have done some good work in autoimmune lupus in mouse models and we published it recently as well. So we are seeing actually very good efficacy of these baffarti cells killing the autoreactive B cells. So that uh obviously will reduce the auto antibbody production and most of the symptoms were um disappearing in mice at least and uh yeah we we checked proteinura in these mice. We checked auto antibodies. Um we were weighing them. We were measuring looking at the hair loss. So all these symptoms actually uh became better after the baffarti treatment. And fortunately now BAFKarti entered clinical trial uh for lupus in Columbus and first couple patients already treated and we are hearing very exciting news that they went into remission um after 1 month.

[00:27:33]That's a great news. So yeah I'm really looking forward for taking baffarti for other autoimmune disease as well because the whole mechanism is all about killing the autoreactive B cells. So we are right now working on uh rheumatoid arthritis and autoimmune type 1 diabetes and we are also working on scleroderma models as well.

[00:27:56]>> You know how exciting. I think uh the one thing that I've learned today is that we have to have you back in 24 months. Um the pace of of change here is just remarkable. I think that um we're very excited uh Rashmi that potentially you'll be able to move osteocaroma into patients you know uh in the not too uh distant future and we know David we're already following your amazing uh results with your ultraast uh preparation and your presentations uh that uh have been seen worldwide at ash.

[00:28:32]So congratulations uh to you. I want to thank both of you for joining me uh today. Thank you to our listeners. To learn more about research at University Hospitals, please visit uhhoss.org/uhress research. Thank you, Rashmi and David.

[00:28:51]Thank you.