Stephen Gould
Analyst · BioWatch News. Please proceed with your question
Thank you, Dr. Marbán. Yes, it has been a very clear presentation of the general approach that we've been pursuing here at Hopkins and that we started a very deep, broad collaboration with Capricor over the past year. We are very excited to be working with Capricor and it allows us to expand our horizons both in terms of basic research, but also in applying the rules of exosome biogenesis and production and targeting to actual real world clinical problems. Our approach is essentially outlined in this slide here, there's a great need to make sure that we develop the exosome platform in an efficient high-throughput way so that we can optimize the production of exosomes, the loading of them, the formulation, the manufacturing, and the targeting. And so what I'm going to start with is talking a little bit about a small piece of the data that we've been collecting about the general utility of exosome platforms for RNA delivery. So one of the questions that you might be thinking of right away is how the exosomes compare to other RNA delivery platforms specifically lipid nanoparticles or LNPs. And so we've undertaken a wide variety of experiments that I'm going to show you a very small piece of our data on that issue. The first thing I'd like to show is a figure here that reflects weight change data in response to the injection of equal numbers of exosomes or equal numbers of lipid nanoparticles and black dots are the weight of animals on day zero. The red squares are the weight of animals three days after the injection. And what we have seen is that exosome injections, they're not engender any gross adverse effects that can be detected upon visual examination of the animals, weighing the animals. And this is not quite true for LNPs in equal numbers of vesicles being injected. What we see is that over a short period of time, LNP injections can lead to a reduction in weight of animals. And reduction of weight is a very useful marker for any kind of treatment that causes animals to feel a bit off. It doesn't necessarily mean there's a horrible toxicity brewing here, but it is indicative of an adverse effect of the treatment. So this is just injecting animals with exosomes. There's no effect, injecting animals with an equal number of LNPs causes some distress to the animals. Now that's just measuring weights of animals, a very easy thing for us to all understand. And we all know when we feel – don't feel well, we tend not to eat as much. But the real key is looking in these animals by detailed histological analysis. And that shown in this slide. Now there's a lot of panels here but to make it a little simpler, let me go through it. The top row are histological samples from control mice, same age, and these were done on multiple animals in each group. The control animals have been examined or morphology of their intestine, salivary gland, spleen, kidney, liver, heart, diaphragm, lung, and brain. And based on an independent histological analysis, these animals are totally normal. And the same is true for all animals that were injected with exosomes. So we're injecting animals either with saline or injecting them with an equal number of exosomes or LNPs. In the exosome injected animals again, the histological report came back normal in all tissues in all animals. The same cannot be said for those animals that were injected with the same number of LNPs. And these LNPs are very similar the same basic composition as the LNPs that are being administered in some of the leading vaccines. So while there was no abnormalities in most tissues, there was an abnormality in most of the animals in their spleen. So what was specifically seen in the LNP injected animals was an increase – a high increase in the amount of red pulp in the spleen and the red pulp is a indication of sort of nonspecific inflammation. And this goes hand-in-hand with the weight loss data that we saw in these paired animals. So to sum up these two pieces of data what we're showing you is that injections of exosomes and large numbers of exosomes has no adverse effects. And this is entirely expected because nearly a century of transfusion and transplantation medicine has demonstrated that the delivery of massive amounts of exosomes into people that is not as associated with any adverse effects. So we're basically just reproducing kind of what the medicine already knows. In contrast, injection of LNPs are mildly inflammatory by this assay. And so that's just the delivery vehicles, comparing LNPs as a vehicle and exosomes as a vehicle. What are the effects of those alone? Well, the next question is, well, how do these delivery vehicles compare in terms of the efficiency with which they can functionally deliver mRNAs. And we have a little bit of data that we can show you today on that. Again, we've done many, many studies on this. I'm just going to show you one little snapshot of the data. So what you're looking at here is the expression of a luciferase, a light-emitting enzyme, that's assayed on cells that are grown in culture. So these cells, obviously, they don't normally emit any light. What we can do though is we can synthesize in vitro, a messenger RNA that encodes an enzyme, a luciferase that can be used to as a marker for how efficiently we're delivering mRNA into these living cells. So again, the particles, the exosomes and cells do not have this enzyme activity. The LNPs do not have this activity. The activity is not strictly present in the RNA. The RNA has to get into the cytoplasm of a cell. It has to be translated into a protein, and that has to be done with a high degree of fidelity, so that protein is enzymatically active, so it can emit light. So once it's made, it's capable of emitting light when given the substrate. So what we've done here is we have control cells that's the bar on the far left, you can see those control cells don't – it responds to the substrate. There's a substrate called DTZ, you add and if the enzyme is present, light is emitted. If you add the substrate to the control cells, there's no activity. That's why all those black circles on control are right at the bottom at zero light emission. Now, when we load a standard amount – a constant amount of RNA into tens of the 11th particles per mil of lipid nanoparticles, we do get good expression of this light emitting enzyme. But when we do the exact same parallel experiment, the same amount of RNA, the same numbers of exosomes as LNPs, we get more light emission, which means we're more efficiently delivering that RNA into the cytoplasm of human cells. And it's being turned into functional enzyme. So exosomes are by this graph, those two bars in the middle showed that, now when you go to high dose administration. And high dose administration is particularly important for therapeutic mRNA delivery, where you're going to have to be delivering a lot of RNA many, many times in order to cure, say, genetic diseases. What we see is that the difference between exosome-mediated mRNA and LNP-mediated RNA delivery is really dramatic. It's now more than a tenfold difference. And as you can see, what happens is that when you've dosed with large amounts of lipid nanoparticles, you get an adverse effect on the expression of the RNA that they carry. So there seems to be an upper limit on LNP-mediated RNA delivery that you don't have with exosome-mediated RNA delivery. And this is a really important point, I know that this is just a tissue culture experiment, but what you see in human cells – in tissue culture, is very often a very good sort of indication of what you'll see in vivo. And I'm going to show you some in vivo data in the next slide, in which we take the same mRNA loaded exosomes, where the mRNA encodes a light-emitting protein, I mean, yes, in terms of light-emitting protein and we're going to actually show you a picture of light coming out of the animals that we've treated. So what you see on the left are couple of animals that received no exosome injections. So they may not receive any of the mRNA loaded exosomes, these animals have been injected with a substrate for this light-emitting enzyme, it's called DTZ. And you see only background just the normal pictures of these mice, and these mice are all alive. On the right are a pair of animals that were injected with our mRNA loaded exosomes, where the mRNA encodes this light-emitting enzyme, the day before. And then after a day to allow the exosome mRNA to deliver that RNA into the cells of the animals, and then that RNA being turned into a protein and that protein folding properly, so that it's enzymatically active. If you then inject a substrate for that enzymes into the animals, the substrate gets to where the enzyme is, and now light comes out of these animals. So you're looking there in red, those are the brightest regions of light emission and the scales on the right and it gives you an idea of how many lumens per second are being emitted in these different areas of the animal, this exposure is just, I think it's just about a minute or so. Anyway, so this is a real time in vivo live animal evidence of protein expression from our RNA loaded exosome formulations. And although this is not a therapeutic on our name, it's not a vaccine in coding RNA, it is showing all the same biochemical, molecular and cell biological processes that would occur in any kind of vaccine development program or therapeutic development program, you're getting a real time light animal version of what gene expression looks like from our formulations. So this shows very directly that our platform can deliver functional enzymes, not just protein, but you can have proteins that are not profitably pulpit, but functional enzymes. And of course this is directly relevant to any kind of gene therapy or enzyme replacement therapy type of paradigms that are out there for viral vectors or enzyme injections. We can do the same thing with exosome based RNAs. Now, I want to say just a little bit about the very earliest work we did on the SARS-CoV-2 vaccine and experiments that actually we performed late last June, early summer on a SARS-CoV-2 vaccine. And just to reiterate our point of view, when we started all this, we wanted to make sure that we could generate at a research level, but also in a manufacturing level safe non-toxic exosome mRNA formulations, which we have achieved. We wanted to not just drive antibody and cellular immunity to the spike protein, but we wanted a broader based vaccine, a vaccine that would drive immunity to the other major structural protein of the virus, which is called nucleocapsid. So we have two mRNAs that we synthesize, we formulated them into exosomes at the same time and we use those formulations to elicit immune responses in mice, and the data confirms that the multiplexed mRNA approach works, we get immune responses to both proteins. Now I'm going to show you this data from our very first study, and I will just preface this by saying that our efficiency of loading RNA is then optimized well beyond this, our antigen vaccine – our vaccine antigen design has been improved significantly, and we're getting much better expression even in this very early studies that we performed. But even in that very early first study, where we had not yet had time to optimize our platform and our formulations, we got very strong immune responses to both the nucleocapsid protein and the spike protein. And the overall regimen of the vaccination and the testing dates as shown in panel A at the top that line diagram below that in B shows that we elicited a strong anti-nucleocapsid immune responses and in C that we generated strong anti-spike immune antibody responses as well. And these antibody responses basically came up very early after vaccination and remained constant out with very little decline out through the end of the study. I’ll also say that our dosing here is quite low, relative to where we are now, in terms of the amount of RNA we deliver, we were only delivering 4 micrograms at that time, we're now up to 30 micrograms, 50 micrograms in our formulations. Not only did we get antibody responses, but the panel on the right demonstrates that we had CD8-positive and CD4-positive cellular immune responses, both to spike and to nucleocapsid. And so this is just a snapshot of our approach, our approach is not limited just to SARS-CoV-2 vaccines, but to other vaccines. And more importantly, what we're really excited is our ongoing studies in therapeutics development. And so, I'm just going to say just a couple of words about that. Our view of the vaccines is that we hope to very quickly help in the fight against SARS-CoV-2 with our vaccine development platform. And we are also in the process of generating a very interesting research studies on other candidate exosome RNA vaccines. We're very interested in the vaccines, but I want to reiterate that the vaccines are a fantastic developmental program with which we are troubleshooting, optimizing the very issues that also has to be addressed and optimized for therapeutics RNA delivery. We have a very strong focus in the area of therapeutics, and we have a number of developmental projects that were in the middle of, at present. And I just want to bring you back to those mice that we looked at earlier, because they really do demonstrate the potential exosome mRNA delivery platform that we've been working on here in Baltimore, and also in collaboration with our colleagues at Capricor, where we are delivering functional RNAs, not just to emit light from animals, but to repair genetic defects in animal models as a prelude towards generating clinically useful therapies. And I think that pretty much sums up what I have to say about the research collaboration and the results that we posted online at bioRxiv earlier this week. And I'll turn it back now to Dr. Marbán.
Linda Marbán: Thank you, Dr. Gould. That was enlightening even to me who talks to you multiple times per day. Now that you have seen this exciting data, let me tell you where we are and our path to the clinic with our multi-antigen exosome-mRNA vaccine. Currently, we're waiting for feedback from FDA on our pre-IND package; we expect to receive that before the end of this quarter. Our current plan is to move into the clinic and aim to initiate a Phase 1 clinical trial and Q3 of 2021, if approved by the FDA. The preclinical data presented late last year was compelling, and we are looking forward to advancing this product into the clinic. Of course, as I mentioned previously, we also view this data as proof of the concept that mRNA loaded exosomes make excellent vaccine candidates, which can potentially be applied to other infectious diseases. Now, let me turn your attention to CAP-1002, our cell therapy product, which is in clinical development for Duchenne muscular dystrophy and the novel coronavirus. I would like to update you on the status of our DMD program first. We remain engaged and focused on the goal of advancing CAP-1002 towards approval for DMD as quickly as possible. Now allow me to recap where we stand. We have conducted two clinical trials using CAP-1002 and DMD, each trial showed both skeletal muscle and cardiac muscle improvements. HOPE-2 our Phase 2 clinical trial showed significant improvements in the pole or the performance of the upper limb, a measure of upper limb skeletal muscle function, and also an ejection fraction, the goal standard of cardiac function. It is important to emphasize that HOPE-2 was the first randomized placebo-controlled clinical trial in Duchenne muscular dystrophy to impact both cardiac and skeletal muscle function. As a reminder, cardiomyopathy is typically the leading cause of death in those with DMD. So any improvement in cardiac function would be considered very relevant for both lengths and quality of life. Now due to our RMAT designations and the importance of this program, over the past year, we have been in continuous conversations with FDA, regarding the approval pathway for CAP-1002 and DMD. This process fall typically not short has been understandably delayed due to COVID-19. We with the help of a cardiac consultants, rare disease specialists, advocates and statisticians are working on additional analysis to support further discussion with FDA on our approval pathways. We expect to have additional clarity and a final decision by the end of the third quarter of this year. Now, while we have rigorously continued to make our case for an accelerated approval pathway, as we have previously stated, FDA has encouraged us to conduct a Phase 3 clinical trial. The design of this Phase 3 trial is that it will be a small and focused study measuring those items that were positive in HOPE-2, the performance of the upper limb, the PUL and the cardiac measures of ejection fraction and volumes. The size of the proposed Phase 3 trial is estimated to be approximately 60 patients. FDA has indicated its acceptance of this study design. Further, we are also in discussions with several parties regarding a potential partnership opportunity for this program. Regardless, management is committed to moving this asset forward, and we are assessing all strategic options available to us. Currently, we are not planning or conducting the trial until we have final clarity from FDA, and then we will determine the appropriate path forward. We look forward to bringing you updates on this very important program as we have them. Lastly, we continue to enroll the INSPIRE clinical trials to treat severe, but not critical COVID-19 patients. This trial is designed for up to 60 patients and has a 30 day readout. We anticipate data from this by the end of Q3 of this year. This trial is important, because it may potentially down-state, the immunomodulatory effect of CAP-1002, which has been demonstrated not only in previous clinical trials, but also in pre-clinical publications over the past few years. Again, we will provide updates as they become available. In summary, as you can see, we continue to support this exciting platform. And I'm happy to say that we have sufficient resources to execute on our near-term plans and have assembled a world-class team of scientists helping us move this technology forward. We continue to pursue non-dilutive sources of capital to fund future clinical work on our programs. I continue to be excited by the progress we were making both in the exosome platform, the latest of which you heard about today, but also with regards to pursuing a pathway for CAP-1002 towards potential approval and commercialization. I will now turn the call over to AJ Bergmann, our CFO for an update on the financials.