My name is Ashram Basavaraj. I am Associate Director of our Bronchiectasis Program at NYU and Section Chief of Pulmonary Critical Care and Sleep Medicine at Bellevue Hospital Center in New York City. And we have a great panel of speakers today. We got Dr. Anne O'Donnell from Georgetown, Dr. Chuck Daly from National Jewish, and Dr. Jonathan Koff from Yale, who are all going to be talking about treatment strategies for bronchiectasis. And before we get into specific treatments, I just wanted to give everyone an overview of the state of bronchiectasis and some important concepts that are emerging for bronchiectasis. So these are my disclosures. I'm a consultant on the advisory board for a number of companies interested in bronchiectasis and a principal investigator for a clinical trial in high-frequency chest wall oscillation therapy with Baxter. So bronchiectasis is an exciting field right now. We have a number of registries that are in process of developing clinical trials and trying to learn more about the natural history of bronchiectasis, with MBARC in Europe being the largest registry really in the world, and then the United States Bronchiectasis and NTM Research Registry, which is a consortium of about 20 sites, centers of excellence across the United States with over 5,000 patients in the registry. With that, we start to learn more about bronchiectasis, develop clinical trials from it, and just learn more about the natural history. So from these registries and from other research that's being done in bronchiectasis, there are emerging concepts that are being developed in bronchiectasis. We have exacerbations and different phenotypes that are emerging, inflammation being a key model in the pathophysiology of bronchiectasis, precision medicine in bronchiectasis and treatable traits, and really trying to identify potential targets for early intervention and prevention of bronchiectasis, with persistent bacterial bronchitis being one of them. So we're going to touch on some of these topics now in this talk. But before we begin, I think it's important to understand what a bronchiectasis exacerbation is, because we want to manage it clinically, treat it appropriately, and really try to reduce the inflammation that's associated with it. So this specific definition came out of ERJ in 2017, and it really states that a bronchiectasis exacerbation is involving deterioration in three or more of the following key symptoms for 48 hours. And that's cough, sputum volume or consistency, sputum purulence, breathlessness, fatigue or malaise, hemoptysis, and a change in bronchiectasis treatment that's required, and oftentimes that's antibiotics that are started for a bronchiectasis exacerbation. And we know that these are bad for patients, right? So there are certain phenotypes that have been described for frequent exacerbators in bronchiectasis, and these exacerbations can have a detriment for the patient. They can have an effect on lung function, symptoms, quality of life, mortality, and it can lead to future exacerbations. So it's important to try to identify these exacerbations and treat it appropriately. And we're also learning that there are certain organisms that are more associated with these exacerbations, and one of them is Pseudomonas being a key one, and this was a comprehensive analysis of over 20 observational cohort studies that showed that the presence of Pseudomonas was associated with increased mortality, hospital admissions, the number of exacerbations, worse quality of life, and a deterioration in pulmonary function and radiographic findings. And from the United States Registry, we looked at specifically with airway clearance techniques, finding that patients who used airway clearance techniques were a sicker population trying to improve their symptoms, and oftentimes had the presence of Pseudomonas, and that higher rates of exacerbations or hospitalizations. So we are understanding that Pseudomonas is often associated with these exacerbations. So now inflammation is key. It's a key model for bronchiectasis, and this is not new in bronchiectasis. This has been described going back to the 1980s with the graph on the left here. That's the vicious cycle hypothesis where we have bronchiectasis from an etiology that leads to pooling of mucus, bacterial colonization, further neutrophilic inflammation, and further destruction of bronchiectasis. And it's important to try to break this vicious cycle that develops, and the idea of the vicious cycle has morphed into the graph on the right, the vicious vortex, suggesting that these four steps that's part of the cycle are all interconnected, and that trying to stop one of these steps still may not, you know, prevent progression of bronchiectasis since they're all interconnected. So airway clearance is an important strategy to try to break this vicious cycle and try to reduce the inflammation, and we're going to be hearing that more in the upcoming talks here. And there's been, you know, good randomized controlled trials that have showed that macrolides and bronchiectasis can decrease inflammation. So with the EMBRACE, BLESS, and BAT trials suggesting that, you know, the use of chronic macrolides can lead to a decrease in exacerbations, pulmonary sputum weight, improved FEV1, quality of life scores, but obviously, you know, the concern with macrolides is resistance that can develop. We want to make sure these patients don't have underlying NTM, and we're not exposing, you know, potential resistance from developing to NTM if they need the macrolides in the future for their NTM treatment. Now there's different types of inflammation that we're learning in bronchiectasis. We know that neutrophils are a major player in inflammation in bronchiectasis, and they're often abnormal. They have prolonged survival, delayed apoptosis, impaired phagocytosis, and the development of neutrophilic inflammation in bronchiectasis can lead to a formation of what's known as NETs, which is a meshwork of DNA and fibrin that attempts to try to kill these organisms, for example, Pseudomonas, but it has impaired killing of these organisms, and it leads to further inflammation, impaired mucociliary clearance, and further symptoms, right? So the development of these NETs, you know, can lead to a deterioration in a patient's quality of life, so a lot of treatments now are trying to target neutrophilic inflammation and trying to target the prevention of these NETs from forming. So one of the medications that's promising, this is a phase two trial of brenzacatib, which was published in the New England Journal of Medicine. This is an oral reversible inhibitor of DPP1, which is an enzyme that's thought to be responsible for activation of neutrophilic serine proteases. In this specific trial, it was found that brenzacatib prolonged time to first exacerbation and also reduced sputum neutrophil elastase activity, and there's a phase three trial that's ongoing right now, and we'll be hearing more about this later on in the session. Now it's not only neutrophilic inflammation that is being phenotyped in bronchiectasis. It's also another cohort of eosinophilic bronchiectasis has been described. This was in the Blue Journal earlier this year. This involves an asthma bronchiectasis overlap with a TH2 phenotype, and it's been described that almost 20% of patients with bronchiectasis can have an eosinophilic phenotype with higher numbers of eosinophils being associated with shorter time to exacerbation. So potentially there could be research interest in developing biologic therapies similar to what we do with asthma and seeing if that can target eosinophilic bronchiectasis as a potential treatment in the future. And then precision medicine and treatable traits. We've heard this in other topics in pulmonology, and that's also being discussed in bronchiectasis, and the idea behind this is that bronchiectasis is a heterogeneous condition, and there's no one-size-fits-all approach, right? We need individualized approach, and endotyping these patients with bronchiectasis is an important strategy that helps to identify specific treatments and try to target treatable traits associated with that. And endotyping these patients with bronchiectasis then allows for further clinical trials, testing and medications, and hopes for specific targets of treatment. This was published last year in Breathe, which is actually a really good article going in depth in terms of precision medicine and bronchiectasis. So this is an example of how we can approach treatable traits in bronchiectasis. You know, bronchiectasis could be diagnosed on a CAT scan. We want to identify the underlying etiology of bronchiectasis, targeting treatments for those underlying etiologies, for example, NTM, ABPA, immunodeficiencies, genetic conditions that could be associated with bronchiectasis, PCD, CF, autoimmune conditions, inflammatory bowel disease, and then trying to target those specific conditions to try to prevent the bronchiectasis from further worsening. With that also, we can further then try to investigate for treatable traits in bronchiectasis. So for example, for those that are endotyped with frequent exacerbations, low-dose macrolides being an option for those patients. Those with chronic airway infections can be considered for long-term inhaled antibiotics. Those with eosinophilia can be considered for inhaled corticosteroids. Those with mucus plugging, you know, think about airway clearance and mucoactive drugs. And also patients who have symptoms associated, specific symptoms associated with their bronchiectasis, for example, shortness of breath, can receive bronchodilators. Those with cough and sputum can have airway clearance and mucoactive devices, and those with fatigue should be considered for rehab, exercise, and nutrition. So this is, you know, one approach on how we can use precision medicine and treatable traits in bronchiectasis. And then finally, we want to see if we can prevent bronchiectasis from even forming, right? So we have this idea of PBB, or persistent bacterial bronchitis, which could be an infection that happens early on in life, which then, you know, is treated inappropriately, leads to chronic superative lung disease, and then with that can have bronchiectasis develop after that. So there is, you know, talk on trying to identify persistent bacterial bronchitis early in patients and trying to treat it appropriately to try to prevent bronchiectasis from forming. So I just want to highlight that bronchiectasis is a heterogeneous condition. It's associated with exacerbations, you know, oftentimes with the presence of pseudomonas. Inflammation is a key model of bronchiectasis, and, you know, an individualized approach with endotyping and treatable traits, you know, is helpful to try to target specific therapies. And, you know, with that background information, we're going to, you know, hear more about specific therapies and bronchiectasis. Just wanted to let everyone know also about the World Bronchiectasis and NTM Conference. This is a worldwide conference that happens once every one or two years around the world. Earlier this year it was in Prague. Next year in July it will be in the United States in New York City hosted by our CME team at NYU. So I encourage everyone to attend if, you know, it's really a great forum to try to get in-depth knowledge about bronchiectasis and NTM. So with that I want to thank everyone and then just want to invite Dr. Anne O'Donnell who's going to go over current strategies of bronchiectasis. Thanks, Ashwin, and thanks everybody for being here today. So Ashwin asked me to talk about current treatment strategies in bronchiectasis and he, you know, set the stage here really well for discussing how this is something to be personalized and individualized to the patient. These are my disclosures. I'm on a number of consulting panels for various products that are maybe in the pipeline for bronchiectasis and NTM. And I'm also PI on a number of studies at Georgetown in bronchiectasis and NTM. So we've seen this before, the vicious cycle of coal. The idea here is that in targeting therapies you want to hit every aspect of the vicious cycle. So we're going to talk a little bit about the neutrophilic inflammation. I'm going to focus on the airway issues, right, the mucus accumulation, the ciliary dysfunction, that's associated with mucus pooling and abnormal mucus clearance, and then treating and trying to attack the bacterial infections that result from the vicious cycle. It's of course more complicated than that, right? I mean, there's just so much going on in the airways of these patients in terms of the inflammatory markers, the impact on the sputum, the impact on the biofilms, how the ciliary functions work in these airways. So we're really just scratching at the surface of understanding this from a more scientific and translational point of view. And hopefully this, Chuck will talk more about this kind of stuff in the next talk, but hopefully we're going to have therapies really aimed at all aspects beyond just sort of the concept of the vicious cycle. Now as Ashwin said, bronchiectasis is complicated, right? It has like multiple different etiologies. So a patient who has primary ciliary dyskinesia as the cause of their bronchiectasis is quite different than somebody who's, say, chronically aspirating and chronically infected for that reason. So we do have to think about these multiple etiologies of bronchiectasis when we consider treatments. And again, Ashwin touched on the treatable traits. Some patients are very productive, bring up a lot of sputum, have CTs that show extensive mucus plugging, cavitation. Other patients are dry and don't bring up a lot of mucus and really a totally different sort of treatable trait that we have to think about when we're planning our therapies for these patients. So in my mind, these are the main tenets of treating patients with bronchiectasis. And I have to say, like, I really want to stress the idea of educating the patient about the disease as sort of the first line treatment. You know, bronchiectasis, the name doesn't roll off the tongue here. And patients and many others stumble with understanding exactly what they have. So I just want to say that I think this education of the patient and also of our colleagues that help take care of these patients is really important. And then I want to understand how impactful the disease is on the patient in order to plan my treatment strategies with the patient. I want to understand the extent of the disease, as I just alluded to, you know, in terms of the radiographic extent of disease, but also the functional status of the patient. And most importantly, when it comes to some of the therapies we use here, I really want to know what bacteria, fungus, AFB organism the patient has in order to pick the right targeted therapy for the patient. So education, you know, we have these posters in our exam rooms to point to these things all the time in terms of helping the patient understand the disease, and also helping why I'm recommending, you know, some of these therapies to the patient, particularly airway clearance, because I think the visual really helps the patient to get the picture of why they need to do some of these things. So the goals of treatment, you know, I view this as maintenance treatments, treatments of exacerbations, and then I'm going to say a word about the concept of eradication of specific organisms in bronchiectasis. And again, we're touching each aspect of the vicious cycle or the vicious vortex when it comes to treating this disease. So number one, after you educate the patient, right, you want to treat the underlying etiology if it can be mitigated, right? So real important to know if the patient has, say, cystic fibrosis that hasn't been diagnosed before because there's treatments that are going to actually alter the natural history of that disease. You know, of course, many patients we don't find an underlying etiology, but it is important to look for that and treat it if possible. And I view the approach to treatment after that as kind of a stepwise. Let's start with airway clearance, and in that realm we have both mechanical devices and pharmacologic agents for airway clearance. Then we go up to anti-inflammatory therapies, and Ashwin mentioned macrolides and inhaled corticosteroids that we'll talk about. And then the next step for the patients who are the frequent exacerbators or the heavily symptomatic patients is targeted chronic antibiotic therapy. And then I'll say a word about exacerbations and eradicating first isolation. So the goal of airway clearance, of course, is to help the patient clear the sputum. In theory, this will help reduce their cough and reduce their dyspnea, hopefully, and also interrupt the vicious cycle of airway damage that's happening because the mucus is retained in these airways. We used to, in the old days, recommend stuff like this. But now, of course, we've turned to other airway clearance techniques. I could spend like an hour talking and trying to demonstrate all these various techniques. There's active cycle of breathing, autogenic drainage, and other modalities that are available to patients and that we need to help them learn how to do these. Now I don't like, you know, huff cough in front of my patients, but I do point them to various resources on websites and, of course, with our pulmonary function techs and our respiratory therapists to help them learn some of these techniques. You know, the data on airway clearance, of course, is not fantastic, but I think there's generalized sort of opinion, expert opinion, if you will, that agrees that this is important in this therapy. Ultimately, what airway clearance is best is the one that the patient will do. These are time-consuming and can be very complicated for the patient, so you really have to hit on something the patient will do. So there are these mechanical positive expiratory pressure oscillatory devices that are easy for the patient to use. There's more complex things like the high-frequency chest wall oscillating vests of various types. And then, you know, the issue of pharmacologic agents for airway clearance, and, you know, the one I think that's captured the bronchiectasis world, if you will, is hypertonic saline. You know, to be honest, the data is really pretty scanty in hypertonic saline, but we do recommend it for many patients. It seems to be well-tolerated. Unfortunately, some of the other things, particularly RhDNAs, which, of course, everybody knows is effective in patients with CF, bronchiectasis is not approved or indicated in at least most patients with non-CF disease. I think, you know, I try to think practical with the patients, too, and I think we need to probably emphasize a little bit more and understand from the patient's point of view how complex doing airway clearance can be, right? You got to clean your nebulizer. You got to find the pieces to it. You got to have somebody try to reimburse you for those things. How we sequence these therapies is pretty complex for the patients. So I think a really good resource online is the bronchiectasis toolbox, and there are some other ones as well, but the toolbox is something from the Australian New Zealand Thoracic Society, and it has videos and everything to show patients how to do these various things. So I would commend that to you as part of treatment. Moving on to just exercise and pulmonary rehab, there is some data that shows the importance and the value of exercise training and also formal pulmonary rehab in patients with bronchiectasis, and you can see these studies here. All right, so you've convinced the patient that they need to do airway clearance, even if it's just walking, you know, using the little Acapella or Aerobica device. And they're still symptomatic, right? They're still coughing up a lot of secretions. They're having exacerbations. So then we sort of step it up to the next level and think about using anti-inflammatory therapies. And Ashwin already mentioned the three main macrolide trials that were done and published now 10 years ago that looked at azithromycin and erythromycin. You know, I think we struggle a little bit with the mechanism of action of these drugs in bronchiectasis, more anti-inflammatory than anti-infective. And there is, you know, there is a risk-benefit ratio, but if the patient is eligible, and I'll get into that in a second, to use a chronic macrolide, it is probably a reasonable strategy in those who are frequently exacerbating. Ashwin also mentioned inhaled corticosteroids. I mean, you know, we have a lot of patients that come to us who are on inhaled corticosteroids already because maybe they've been told they had COPD or asthma. I think we have to use ICS with caution in our patients who are chronically infected because of the risk of the steroid exacerbating the infections. But as Ashwin mentioned, there is an asthmatic type of bronchiectatic patient that probably does benefit from this. So okay, you've done airway clearance, the patient is cooperating with that stuff, and then you've thought about whether to put them on a macrolide or not, and yet they're still having problems and they're still having exacerbations. So, but even prior to this, you've learned what organism your patient is chronically infected with. And I can't stress this enough. I mean, we really need to be doing routine microbiology on all of our patients with bronchiectasis so that we can understand, if we need to, how to target specific antibiotic therapies at these patients, and also what to treat them with when they exacerbate. I mean, I think it's just vitally important to know what organism they're infected with. And about a third of the patients, for example, in our U.S. registry have chronic pseudomonas. So sometimes I think there's a tendency to equate bronchiectasis with pseudomonas, and many patients have lesser organisms, if you will. And of course, a lot of our North American patients have NTM. So turning to the idea of maintenance antibiotics, if you look at the guidelines that are currently out there for the treatment of bronchiectasis, the recommendation is basically patients who are having three or more exacerbations per year. The evidence for using maintenance antibiotics is mainly for patients who are infected with pseudomonas. And there's a lot of issues with this. I mean, we really don't know what to do with patients who are, say, MSSA colonized, or have other organisms that they frequently exacerbate, but we may not have a specific targeted treatment. But I do think, particularly in your pseudomonas patients who have not succeeded on the first-line therapies, that targeting an antibiotic is reasonable. Unfortunately, though, it's sort of a sad story of trials for anti-pseudomonal inhaled agents in non-CF bronchiectasis. And this is the list of trials that have sort of come to naught. Although, of course, we still do use, particularly the aminoglycosides, not FDA-approved in patients with bronchiectasis. The latest updates on inhaled antibiotics, people are re-looking at, James Chalmers' group re-looked at the inhaled S-treonam trial, did a post-hoc analysis, and they found in that the most frequent exacerbators actually appeared to benefit from that. The tobramycin podhaler is being looked at again. And a study of great interest to us is inhaled colistin. Of course, that can be prescribed off-label here, but it's not approved. But there is a trial, the PROMIS trial, with two arms, PROMIS-1 and PROMIS-2. Only a small amount of data has been released, and we'll have to see what's gonna come of that. So bottom line, when you're talking about using a chronic antibiotic strategy, I kind of think of it like this. You know, choose a macrolide if the patient is frequently exacerbating and can tolerate the macrolide from a GI, et cetera, point of view. I generally use azithromycin 500 three times a week as that strategy. And really, the contraindications to chronic macrolide therapy are if they're co-infected with NTM, because you don't wanna use macrolide monotherapy in NTM patients if they have certain cardiac issues, and you do have to be aware that a macrolide can cause hearing loss. I switch the gears to inhaled antibiotics if either they fail or they can't do macrolides. And then I usually, again, totally off-label, because none of this is approved, use an inhaled aminoglycoside if they're infected with an appropriate organism, and then think about those other ones. So to summarize, I wanna stress the need for a stepwise and individual approach to patients. The therapies that I see in that upward step, of course, one is patient education, two is sort of routine pulmonary care, you know, immunizations, good nutrition, no smoking, no marijuana smoking, et cetera, but then move up to airway clearance, consider the anti-inflammatory therapy, but use with caution, think about maintenance antibiotics for the frequent exacerbator, and then up to inhaled antibiotics. And I just wanna, again, stress that things should not routinely be used are inhaled corticosteroids, so could not routine, indicated for some patients, certainly no routine oral steroids, and to avoid macrolide monotherapy until you've ruled out coexistent NTM infection. A word on acute management, so treatment of acute exacerbations is to target the organism, and I think, as I said before, it's really helpful to know what organism your patient has chronically so that you can speed up the process of treating an acute exacerbation. Ashwin showed us the definition that we came up with for an acute exacerbation, and I think we can't stress enough how important it is, one, to prevent exacerbations, and two, to nip them in the bud as soon as we can, because one exacerbation puts the patient at risk for more. And finally, the question of eradication. This is something that's gained wide acceptance in cystic fibrosis bronchiectasis. Again, we're sort of in a data-free zone, more or less, for treating, eradicating, quote-unquote. So the idea of eradication is that at the first identification of particularly pseudomonas in a patient that you're caring for for bronchiectasis, that you will do an aggressive anti-pseudomonal regimen when you first identify that organism. And an aggressive management would be probably two or three weeks of either targeted oral or IV drug plus an inhaled antibiotic. And probably the best data from a retrospective observational study is the one I mentioned here. Peters et al. in the European Respiratory Journal, a Dutch observational study, where they had a 73% quote-unquote eradication rate. Their definition of eradication was that it didn't come back for six months. So I'm not sure where we are with this, but I do think that if you're following a patient and they have haemophilus, haemophilus, haemophilus, and then all of a sudden their first pseudomonas identification, you might wanna consider this strategy. And finally, sort of end of one therapies, very personalized treatment for bronchiectasis includes surgery, either for very localized disease or for extirpating the worst area of disease. Of course, a small number of our patients progress to needing lung transplantation. And although we don't have time to talk about this, there are some patients who might benefit from anti-reflux therapy if aspiration is the cause of their bronchiectasis. Again, so to just wrap up here, I would say stepwise treatment, individualized, personalized, treat the underlying disease, identify the infecting organism, really work with the patient on getting buy-in on airway clearance and exercise, assessing what the bronchodilator ICS need is, macrolidin-selected patients, and then maintenance antibiotics, and finally, clinical trial enrollment. So thank you. I'm gonna hand the podium over to Dr. Daly, who's gonna discuss some new treatment options. Thank you. Thank you, Anne. It's a pleasure to be here, and it's great to see this many people here on the last day. Everyone has seen this figure. a hundred times, and you'll see about 99 more in the next 15 minutes. So these are my disclosures. I'm involved in advisory boards, consultancies, research grants, and I serve on some data monitoring committees. So I hope in the next 15 minutes that you'll be able to describe the importance of neutrophilic inflammation. We've heard hints about it from the previous two speakers, and explain the potential benefits of inhibiting serine proteases, and we'll go into some detail on that. And then I would like to share with you some things that are happening in terms of current trials. Hopefully you'll be excited when you see that. So how do we interrupt this vicious cycle or this vicious vortex? One way is to focus on the role of the neutrophil. We know that patients with bronchiectasis have frequent exacerbations and they're often neutrophilic in their inflammatory pattern. And the neutrophil is by far the dominant inflammatory cell in the airway of bronchiectasis patients. These neutrophils, though, they contain something which are called serine proteases, or NSPs for short, including a very important one, one of the dominant ones, which is neutrophil elastase. So neutrophil elastase is an enzyme. It belongs to the chymotrypsin family, and it can do a lot of bad things in the airway. It can affect the extracellular matrix and cause destruction of that, something we are all very commonly seeing in our patients is mucous hypersecretion, reduction of ciliary beating, therefore another impairment of airway clearance, and it can literally directly damage the airway epithelium. And it's also been shown that neutrophil elastase is associated with disease severity, it's associated with bacterial load, and also clinical outcomes. And this is just a picture you saw earlier of this very complex inflammatory process that's occurring at the epithelium, and neutrophil elastase has multiple roles in that inflammatory cascade. So these are examples of how neutrophil elastase has been associated with severity of disease. This was published by James Chalmers. And what you see here on the y-axis is the activity of the neutrophil elastase in this sputum. And then across the x-axis we see a bronchiectasis severity index score from mild, moderate, to severe. And there's a very strong statistical trend here showing that neutrophil elastase goes up based on severity of disease. It also goes up based on bacterial load. So here on the x-axis we're looking at the bacterial load, and again we can see highly statistically significant this increase in bacterial load as neutrophil elastase levels are going up. I think more importantly is that this has been associated with longitudinal outcomes, exacerbations as well as time to next exacerbation. So on the left what you see is the rate ratio of exacerbations, and on the x-axis the patients are grouped into those who have severe exacerbations and those who have moderate. And then within that grouping we're seeing different levels of neutrophil elastase. And it turns out if it's over 20 micrograms per milliliter is associated with increased risk of severe exacerbations. And then on the right side we can see that we're correlating time to the next exacerbation, and again highly significant finding that neutrophil elastase activity is associated with a shorter time to next exacerbation. So this appears to be important in the pathogenesis. So then let's go inhibit neutrophil elastase. It's been done. Two randomized trials, one phase one trial. These have been published. These were 2A, the first two were phase 2A, 38 to 94 patients given it only for 28 days. The primary outcome was reduced sputum neutrophil count, and unfortunately in that study it was not achieved. And the other looking at pulmonary function and quality of life measurements also not achieved. In the first there was a significant increase in the FEV1 and a positive trend in the St. George respiratory questionnaire. The final one is a phase one, so it's really looking at adverse events. It's a completed enrollment, but there's no data. But we shouldn't be too worried about this I think. These were very small studies. They were very short duration of therapy, and we've heard already that not everyone that you enroll is going to have neutrophilic necessarily inflammation. So I think that we just have to take these studies for what they are, small. But that was going after neutrophil elastase, and that's just one of the neutrophil serine proteases. There are others that we saw earlier in Dr. O'Donnell's slide. So this is a very important concept, which is what if we were to somehow block all of them? So DPP1, dipeptidylpeptidase, also known as captexin C, is a protease, and it cleaves neutrophil elastase, but it also cleaves other NSPs like captexin G and protease proteinase 3. This occurs during the maturation of the neutrophil in the bone marrow, and in the bone marrow these NSPs are packaged in the azurophilic neutrophilic granules, and as they mature they're then released into the systemic circulation where they eventually wind up in an inflammatory site. So what would happen if you were to inhibit DPP1 and knock out all of these NSPs? Turns out it's been done. It's been done in nature. This is a syndrome called papillon lefebvre, which is PLS. This is a rare autosomal recessive ectodermal dysplasia characterized by thickening of the palms and the soles, and you can see examples also over other joints. It's also associated with early onset periodontitis, but what it's not associated with is an increased risk of infections, of other infections. So you can knock out this DPP1 because of this mutation in the CTSC gene, and patients develop unusual things, but they don't seem to have an increased risk of infection. So then what if you were to refine that and not knock it out, but just reduce the activity of the enzyme? Well that's been done, and so brentacatib is an oral reversible potent inhibitor of DPP, should be DPP1. So enter willow study. This is a phase 2 trial published by James Chalmers in the New England Journal, and this is a DPP1 inhibitor, and as I said it's reversible. So this was a randomized control study. You can see the design. Patients were randomized in a one-to-one-to-one fashion to either 25 milligrams of brentacatib, 10 milligrams of brentacatib, or placebo. They were treated for 24 weeks, and then they were followed for four weeks. Primary endpoint was time to first bronchiectasis exacerbation. There were other important secondary endpoints like the rate of exacerbations, change in quality of life, change in percent predicted FEV1, and change in neutrophil elastase activity. This is the primary outcome, and the willow study met its primary outcome. This is looking at the proportion of patients with no exacerbations, so the higher the line the better. You can see both doses of brentacatib were statistically associated with a prolonged time to first exacerbation compared with placebo. In fact it's quite significant. They also made the important secondary outcomes. This is the frequency of exacerbations. So this is looking at the percent of patients who've had zero, one, two, or three exacerbations. And if you look at to the left, those who had zero, you can see that both doses of brentacatib had were significantly less likely to be associated with an exacerbation. And in fact, the severe exacerbations were about half that of placebo. And maybe not unexpected, but I think it's important to understand that the neutrophil elastase activity in the sputum decreased also significantly, and it was dose dependent. Also importantly, when you stop the drug, you can see within four weeks it was back to baseline. So it's reversible. So that's led to a study, the Aspen study, which Ashwin mentioned. This is currently enrolling. It's a phase three study, 52-week treatment of brentacatib. Pretty large study for our field, 1,600 patients are targeted. The design is the same as we just saw, because as you noted, the two doses look like they worked about the same in the phase two, and hopefully the phase three will tease out, give us a better idea of what would be the best dose. The primary outcome is different. It's the rate of pulmonary exacerbations. That was actually a secondary outcome in phase two, and what was the primary outcome, which was time to pulmonary exacerbation in the phase two, is now a secondary outcome. And these are just others that are being measured. We also heard that's not the whole story, though, because there's this other endotype that's been called the T2 high endotype, and basically it's patients who have eosinophilic inflammation. This is a study looking at various cohorts of non-CF bronchiectasis patients in Europe, also Israel, and very similar, but about 23% of these non-CF bronchiectasis patients had blood eosinophil counts of 300 or greater. Now remember, the rest, most of it is still neutrophilic, but they are different than the other group in that they have this high eosinophil count. And also, we know anecdotally speaking that if you treat these patients with an anti-IL-5 or anti-IL-5 receptor antagonists, like Penrelizumab, we see good outcomes in these patients. Their exacerbation rate goes down. This is just an example. Five patients who had severe eosinophilic asthma who got one of these two agents, you can see they were exacerbating on the y-axis one to six times a year. In over 24 months, look what happened to their exacerbations. So it's, you know, anecdote, it's very impressive. So that led to the Phase 3 Mahale study, but unfortunately after enrolling over 100 patients, the sponsor has decided to close the study. It's not because it's not working, because they don't know yet if it's working. This was presumably a business decision, but that is now off the list as a Phase 3 study. We do have an open label study that is enrolling in Italy, Mepelizumab, and so hopefully we'll get some additional data beyond the anecdotes that I just shared with you about how patients with severe eosinophilic asthma and bronchiectasis do on these treatments. Finally, there are a number of other things that are being studied. This is pretty exciting, because this actually means we have a drug pipeline for the first time in bronchiectasis. You can see from Phase 1 through Phase 3 studies that are occurring. These are recruiting. One is already completed. A lot of different kinds of things, nebulized plasma-derived immunoglobulin. The ARENA1 is an inhaled ascorbic acid glutathione. That is, first patient in should be this month, so that trial is enrolling now. Phase 2a, we have phosphodiesterase-4 inhibitors, CFTR potentiators, capdessin C. So capdessin C, remember, is the same thing as DPPI. So this is a similar approach to the Aspen study, but at a phase two level. And then, as I joked the other day, we cannot find a use for BCG. So we keep trying to find a way to use BCG, and it is being studied in bronchiectasis. And then a large study in Europe of hypertonic saline and carboxysteine. And then, as I mentioned, what has completed enrollment, ACD, which is CXCR2 antagonist, but no data yet on that. So very exciting to me that we actually have all these trials that are occurring. So I'll summarize just by saying what you've heard. Exacerbations, exacerbations, exacerbations. We wanna treat them, we wanna prevent them. Neutrophil elastase looks to be important in the pathogenesis because it correlates with disease severity, bacterial load, and outcomes. And inhibition of DPPI with a brinzacatabin, potentially other agents in the future, has been associated with these very positive findings. And excitingly for me, new drugs look like they're coming. And the theme is they're mainly targeting inflammation, either neutrophilic or eosinophilic inflammation. Thank you very much. Chef said to do that. Thank you. Great job. Thanks. Thank you. Thanks, Chuck. Great talk. Oops, let's see here. All right, so we're gonna hear from Dr. Koff now regarding specifically phage therapy in bronchiectasis, which is again an exciting field. Dr. Koff. Thank you. Great, thank you, Ashwin. Really appreciate the opportunity and invitation. And so what I want to, I guess in terms of my background, with Paul Turner and Ben Chan, we started a phage center at Yale. And from a disclosure, I am required to tell you that the university has licensed the IP for phage therapy to a company. I don't have any role in that. I'm also PI on our single center study called PSYPHY, which stands for cystic fibrosis bacterial phage therapy at Yale. This is a single center inhaled single phage for pseudomonas. And by comparison, we're also doing a multi-center trial within the CF community sponsored by Biomics, which is using a cocktail phage therapy approach. And so what I wanted to do today is really start us off with kind of a biology of bacteriophages, so we're all on the same page in terms of what are the opportunities and definitely limitations with this. And talk a little bit about phage therapy with a lens towards how it's been used for respiratory infections with some recent publications that are, I think, really exciting. And then I have a case of non-CF bronchiectasis to go over with you in addition to some of our CF experience hopefully to be able to show you how this can be potentially implemented for patients and kind of where it could move as a potential future therapeutic. So phages, bacteriophages or phages, are viruses that are gonna specifically infect bacteria. So they're incapable of directly infecting a human cell, which suggests a level of safety that is obviously being explored. First discovered in 1914 by Dr. Tort in England. And then follow up on Dr. Jarrell, who I'll talk about in the next slide, had a huge impact on the development of phage therapy. So phages are everywhere, ubiquitous. Wherever you find bacteria, you're gonna find phages. So the idea is that there are more phages on Earth than any other organism, more phages than stars that you see in the sky kind of idea. And phages outstrip bacteria about 10 to one, suggesting that we should be able to go out there and find environmentally sourced phages that can infect and kill specific bacteria that we're interested in. We're gonna focus on lytic phages, and I have the life cycle here on the right. And this is for kind of two important caveats. The first is that you're gonna give a specific phage here in this diagram, and you can see that it's gonna replicate through the course of its infection and life cycle within a specific bacteria. Let's say this is Pseudomonas, for example. And it's going to then propagate and lyse the bacterial cells. So one single variant can lead to multiple progeny, suggesting that this is a self-amplifying process, right, which is a unique kind of aspect when you think about it from delivering the therapy. And the second is that we want this process to limit the ability of the phages to transmit any type of genetic material to the bacteria. And so that's why we focus on the lytic pathway. The lysogenic pathway obviously has some evidence of communicating that genetic material and increasing virulence. We have to be very careful about that. Some characteristic of phages that I think are really interesting to Nansia bronchiactasis in particular, some of the phages will actually secrete enzymes that'll degrade biofilm, so you can see an interaction within this complicated vortex that was described in terms of the ability of phages to get in there and get to the target bacteria. And the specificity I think is really interesting, right, where a single phage can target a specific bacteria, and this gets us to a concept of personalized medicine. So the basic concept of phage therapy is really, you know, the enemy of my enemy is my friend, right? Can we find these phages out there to kill bacteria that are pathogens and use them to benefit our patients? Dr. Jarrell actually spent some time at Yale, so the company that Paul Turner started is actually called Felix Biotechnology in his honor. And so we've been able to track down some of his records at Yale, which is a lot of fun. But he actually went to the Tbilisi, Georgia here, which is now, their phage therapy center is now called the Ilava Institute, Eliava Institute, sorry, in honor of Dr. Eliava. And early on in the 1900s, Dr. Jarrell was treating patients with phages that they isolated for a variety of diseases, really started out with dysentery. So a lot of this literature is in Russian, but if you go into the literature carefully, you can find folks that have helped us out by translating a lot of the experience from Russian into English. And I've been able to track down reports of over 350,000 cases. The concerns are really obvious, right? The randomization, standardization of the therapy, consent, all sorts of problems in terms of kind of how the studies were done, different markers of efficacy. But what's interesting is their range of delivery that was used, oral, IV, sometimes, although less frequently, nebulized. And approaches included single phages or cocktails. So a huge number of patients have been exposed, and so I think it's encouraging about safety, but clearly has some holes that need to be worked through. So if you look now into the modern literature, this paper from 2020 kind of summarized the existing cases of phage therapy. The vast majority of them were compassionate cases in clinical trials. I don't think we need to go into kind of all the aspects of this, but the basic idea is that we're seeing this real uptick in the use of phage therapy, in particular in compassionate cases with a few clinical trials. And on the right, I'm showing you a variety of programs that have been developed over this time period across the country that are contributing to our use of phage therapy. These are either programs that are developing the phages or producing them in quantities for, sorry, not in quantities, but are producing them so that we can use them in compassionate cases. And some of the programs have experience with directly delivering phage therapy to their patients or helping other providers do so at other institutions. So in terms of respiratory disease, I'll highlight this paper for you that just was published in ERJ earlier this year on the left, and they're looking at the use of phage therapy in respiratory infections. And here you can see we've got compassionate cases, so we've got case reports or a small case series. So it's 15 patients total, and there are two clinical trials, one for post-COVID ventilator-associated pneumonia where there were four subjects, and one subject was enrolled in a study for MRSA pneumonia, really was looking at safety. And at the same time, on the right, we've got the group from Dr. Dedrick and Dr. Hatful at University of Pittsburgh that were publishing their experience with non-tuberculous mycobacteria phage therapy, and in particular with M. abscessus. And so they did a great job of showing you that there's a lot of subjects are sending samples to them, but they, for a variety of different reasons, are able to come up with phage therapy for 20 cases. And they used a cocktail approach, some really interesting science in terms of engineering phages so that they were specifically lytic and would work across the NTM that they were trying to treat. And they used IV therapies, and in some cases, also combined it with inhaled therapy. And so the basic kind of concept for CF and non-CF bronchiectasis is, and it's great for our patients here because they can expectorate sputum, right? So we can then go to the laboratory and take a look at the pathogens. We actually prefer a fresh isolate at Yale because we're gonna go through the process of trying to identify all the pathogens that are in the sputum. But you can also, sorry, go through the process of isolating the M. abscessus, for example, pseudomonas and MRSA. We then bring that over to our phage library, right? So we've got, in some cases, 100 phages, a thousand phages that we can screen depending on the pathogen. And here's just an example of what that screen would look like. You basically grow up your bug on a lawn, and you drop on your different phages. And in some cases, this can be done in much more of a high-throughput setting. And then you're looking for what phages are going to be effective. And we also, obviously, are in the process of characterizing these phages so that we can make sure that they're lytic and make sure that we have good characterization of them before we use them in patients. The other steps that are required is this under number one here is really important, right? Each of these are FDA single patient expanded access INDs or investigational new drug applications. These are emergent or non-emergent. There are mechanisms to do larger cohorts, and that's dependent on working with the FDA and institutions to do an expanded access IND. But at this point, I think the vast majority of cases fall under this. And each institution's IRB's approval is gonna be different depending on how they treat these INDs. For us, we have some experience with cystic fibrosis patients, and I'll just show you a little bit of that data. We're hoping to add this to the literature. And these patients were treated inpatient or outpatient, nebulized phage, twice a day if they were inpatient, once a day if they were outpatient, and the duration of therapy was typically seven to 10 days. We looked at sputum and then clinical outcomes, and all these patients were treated for multidrug-resistant or pandrug-resistant pseudomonas. And all of them had either finished antibiotics before their pseudomonas pathogen continued to have pseudomonas or were concurrently on antibiotics. And so what you can see on the left here is the pre-phage therapy compared to the post-phage therapy, which was about two weeks after we finished the therapy. You can see this decline in CFUs or bacterial load of pseudomonas. One of the interesting things is we have a combination of both cocktail and single approaches for these patients. And what we're doing actually in this strategy is we're showing you that the phage is sensitive, the bacteria is sensitive to the phage at the outset. But our strategy is actually to drive resistance, and in doing so, to force the bacteria in the lung to decrease virulence factors or increase antibiotic sensitivity by down-regulating an efflux pump, for example. And we think that that combination is helpful because on the right, what you're seeing here in terms of pre-phage therapy, FEV1, we see a small but potentially significant increase for all of our patients. And obviously, the patients who had FEV1s above 40% predicted had a larger increase. So this was, I think, kind of exciting for us with the potential that this approach that we're using could have an effect on FEV1 by combining the effect of decreasing bacterial titers and also by decreasing virulence. In terms of non-CF bronchiactasis, so I appreciate everyone before kind of talking about how to characterize these patients. So I'm gonna give you an example of a patient that I met in the hospital several years ago, actually, and he's been, he's a local celebrity. He had underlying COPD, but then he, celebrity for all the right reasons, he's a firefighter, and he went into a building to save two people without equipment because of the emergent situation. And so he had a smoke inhalational injury that developed bronchiactasis. So lovely gentleman, and when we met him, he had a pulmonary exacerbation, and it was characterized by two things. He had multidrug-resistant pseudomonas, and it was sensitive to tobramycin, but his prior experience with tobramycin had developed acute kidney injury, so we were very nervous about that. And so we were asking about the potential for phage therapy. The patient was interested, and we went about an approach to treat him in the hospital and then follow him outpatient and treat him on the outpatient side. And so if you look on the upper right here, you can see that he was on tobramycin again because that was the only antibiotic that was available at the time, but watching him very carefully. And a week after he was on tobramycin, we initiated phage therapy, and you can see that there was a decrease in his bacterial load to a level that we think is probably pretty good baseline for bronchiectasis in terms of being able to have a host response and using airway clearance that could potentially lead to better outcomes. Interestingly, within our approach, we actually did move from a Cipro-resistant bug to a Cipro-sensitive bug after this therapy, which we're investigating quite carefully because that was a little bit of a surprise to us based upon the phages that we used. And then we actually returned to treat him on the outpatient side a month later, and he continued to respond very well. And actually, he's one of the, they describe him as snowbirds, right? So hangs out in New Haven, Connecticut and then goes to Florida in the wintertime. And in Florida, he did not have an exacerbation through the course of the winter and actually sent us some sputums and we couldn't culture Pseudomonas. So that was pretty exciting. The follow-up actually was that he returned to us on and off and eventually did regrow his Pseudomonas, which is not that much of a surprise for structural bronchiectasis, but at one point was also having exacerbation with an ESBL E. coli. And so this was another opportunity for us after he had received antibiotics for us to add on phage therapy. And this is an example of using phage therapy for Pseudomonas and at the same time E. coli. So it was the first time that we had done this. And obviously opens up some opportunities for us to think about this in other diseases, right? We insist that fibrosis potentially treating MRSA and Pseudomonas at the same time. And this treatment actually has been much more longitudinal. So we're putting together this case report and the use of phage therapy clearly has cleared the E. coli. We're not seeing that again. And we saw, again, a significant decrease in Pseudomonas back down to that 10 to the third level. And we've been following him over time to see when does the Pseudomonas recrudesce and is there an opportunity for treatment? And we've actually on and off treated him for four times over the course of nine months with him having disease stability, not requiring inpatient admission. And we're going through the process of characterizing the bacteria and also looking at his sputum transcriptomics and metagenomics to get a much better understanding of what are the interactions between the bacterial changes and also the host inflammation. So I've gone through this quickly, but I wanted to summarize here the idea that there's increased interest in phage therapy as we have multi-drug-resistant infections and sometimes pan-drug-resistant infections. And the potential to find a phage out there, manipulate that phage genetically if needed to then deliver it to our patients in a very personalized case-based approach is encouraging from a safety perspective and also potentially efficacy. I think specifically for non-CF bronchiectasis, we absolutely need to have a conversation about bringing in consideration for clinical trials so that we can be sure about the potential effects of a single phage on the bacteria and the microbiome. We have done microbiome analysis on the CF patients that I described, and there's no change in the overall percentages of bacteria and in particular known CF pathogens. So when we decrease Pseudomonas, we don't see increased Burkholderia or MRSA or Stenotrophomonas as we try and decrease a particular bacteria in that niche. The trials in CF are underway, and they're addressing I think three particular areas, a cocktail approach in stable patients with Pseudomonas, a single phage approach for Pseudomonas, and there's a trial that is just about to start enrolling patients looking at IV therapy with the potential that that could access areas in the bronchiectatic lung that may be more difficult to access from the inhaled approach. And so I talked about that here in terms of IV delivery versus inhaled delivery. I think inhaled makes a lot of sense to me in terms of the ease of use for our patients and also the decrease in terms of systemic exposure so that we're not affecting the gut microbiome. But those kind of presumed considerations need rigorous investigation. Cocktail versus single, I've alluded to, there are I think important caveats to both of them, especially in the context that bacteria will become resistant to the phages that it's exposed to almost under all circumstances. So whether we use a cocktail or a single, we just have to be cognizant of that. I think a cocktail approach is probably gonna be what we want during an acute exacerbation so that we can try and cover as much of the potential bacteria like Pseudomonas. But in terms of a chronic therapy, I'm leaning towards a single sequential approach where we can use different phages over time to target different aspects of the bacteria and try and make them less virulent. And then I think the biggest kind of longstanding black box here is what's gonna happen from a regulatory and commercial perspective in order for this to see the light of day as an FDA approved intervention. But I think we are making strides and companies are communicating with the FDA and we're getting some encouragement that the potential of a phage library as the intervention could be approved and the library is treated as the kind of drug investigation or as the approved drug. And so whatever the phage is within that library is then delivered and all of the phages would reach the same rigorous criteria for use. And with that, I just wanna say thank you in particular to Paul Turner and Ben Chan who are part of the Phage Center and my collaborators and colleagues at the CF program that have helped get all this done. Thank you.

Phage therapy

respiratory infections

bronchiectasis

bacteriophages

bacterial pathogens

bacterial load

personalized approach

biofilms degradation

antibiotic resistance

clinical trials