The Immune-Aging
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Burstcast / Joan Mannick
How We Know · Burstcast

Joan Mannick on mTOR and immune aging

Can a drug improve immunity after 65?

Joan Mannick, M.D., joins Amit Agrawal, Ph.D., and Julia Majewska, Ph.D., for a Burstcast conversation about mTOR inhibition, immune aging and what human clinical trials can—and cannot—establish.

Recorded · Published on YouTube · 1 hour 6 minutes · English

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Joan Mannick in conversation with The Immune-Aging ProjectWatch on YouTube ↗

The published conversation · Opens on YouTube

Joan Mannick

The question behind the conversation

Earlier studies reported encouraging findings in vaccine responses and respiratory infections. The later RTB101 phase 3 trial did not meet its primary endpoint of reducing clinically symptomatic respiratory illness. In this conversation, Mannick discusses what those different results mean for interpreting immune function and designing future trials.

Did the RTB101 phase 3 trial demonstrate fewer respiratory illnesses?

No. In the published trial, RTB101 did not reduce the proportion of participants with clinically symptomatic respiratory illness compared with placebo. The primary endpoint was not met. Changes in antiviral gene expression did not establish that clinical benefit.

Why distinguish an immune measurement from a clinical outcome?

An antibody response or change in gene expression measures one aspect of immune activity. A trial that measures illness asks a different question. At 16:58, the discussion asks what an improved vaccine response actually means; at 27:14, the conversation turns to the choice of clinical endpoint.

Does the conversation establish a treatment recommendation?

No. Mannick discusses hypotheses about infection severity, participant selection and future studies. These interpretations do not turn a negative primary result into demonstrated clinical efficacy. The conversation is for scientific education.

Evidence and context

  1. Mannick and colleagues: phase 2b and phase 3 randomized trials. The Lancet Healthy Longevity, 2021. DOI: 10.1016/S2666-7568(21)00062-3.
  2. Original Burstcast recording and published chapters, The Immune-Aging Project, 8 April 2026.

The summary was prepared from the recording, its published description and the cited trial report. A transcript of the published edit appears below.

Transcript

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This transcript follows the published YouTube edit. Captions were lightly edited for readability and checked against the original Riverside transcript, with corrections supplied by Amit Agrawal. Timestamps link to the published recording. Speaker labels follow the corresponding Riverside exchanges; brief overlaps are labelled jointly.

Conversation sections

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0:01 · Opening: aging and resilience

0:01 Amit Agrawal

Hello everyone. Before we bring our guest in, let us frame where we stand today in modern medicine and aging science. Modern medicine is built on a mechanical idea. We treat the human body like a car. If the spark plug breaks, we replace it. If the heart fails, we treat the heart. We have organized our system, our hospitals, our trials, our regulations around fixing broken parts. For a century, this system has served us well. But the human body isn't just a machine. It is a self tuning system where the failure in one node ripples across the rest. And treating aging by chasing individual diseases faces a mathematical limit. It creates a gap in how we understand systemic failure. The systemic failure behaves like a sand dune. For decades, sand piles up. The system looks stable. You measure it yesterday, it's fine. You measure it today, it's fine. But the physics of the pile are changing silently. The instability is building up inside. Then one grain of sand lands, a flu, a fall, a minor surgery, and the whole side of the mountain collapses. Medicine today is excellent at reacting to the collapse.

1:25 Amit Agrawal

We treat the fracture. We treat the pneumonia. We treat the stroke. We are masters of the landslide. But we haven't yet developed the tools to see the accumulation of the sand. This brings us to the true frontier. We are standing on the edge of dark matter of human biology. We see it exists. We see its gravity. We this we see this gravity in play when a 80-year-old bounces back from surgery while a 60-year-old fades away. We call this resilience. But we but because we cannot yet put this dark matter in a test tube or give it a disease code, our regulatory system cannot yet capture it. We are measuring the visible stars, the diseases while trying to infer the gravity that holds the galaxy together.

2:26 Amit Agrawal

And this is the structural challenge. Two people can look the same on a medical chart, but one has a stable sand dune and the other one is one grain away from collapse. We know the difference intuitively, but we do not yet have approved ruler to measure it. And until we can we can measure the dark matter, we cannot approve drugs that fix it. We are exploring the most important territory of human health with a map that is still being drawn. Which leads to a radical possibility. The defining challenge is not just designing the molecule. It is capturing the signal of the dark matter. It requires a different lens not about a part, not about parts but about patterns. It requires finding a signal that tells how stable the sand dune really is before the landslide starts.

3:34 Amit Agrawal

So the scientific question becomes precise. If the instability of sand dune is driven by hyperactive signals, can we stabilize the structure by targeted inhibition? We are asking if a pathway essential for growth eventually becomes the driver of dysfunction and if we selectively inhibit that signal, does the immune system fail or does it paradoxically reverse the exhaustion and recover its function? We are no longer asking if this mechanism exists in biology. We are asking if we can harness this paradox to restore resilience in the human. To help us explore this frontier, please welcome Dr. Joan Mannick. And to lead the dialogue, my colleague Julia Majewska. Julia, the floor is yours.

4:30 · Introducing the clinical research question

4:30 Julia Majewska

mTOR has been in the spotlight in longevity research for already quite some time. It has been two decades since inhibition of protein called mTOR was shown to extend lifespan in yeast and then in other model system including worms, fruit flies or mice. This discovery brought substantial interest of translational science to come up with strategies that would prove successful anti-aging interventions for human. Today I'm very glad to have with us Dr. Joan Mannick will share with us clinical studies on mTOR inhibition in enhancing immune system function in people and focusing more in on immune system function and in the context of respiratory diseases and vaccination. Please join we are very happy to have you with us. I would be very I would like to start in understanding what were the questions when you joined the field and what were the questions what was known what were the questions where the field was standing and how did you decide to address them?

6:05 Joan Mannick

Sure and thank you so much Julia and Amit for inviting me to this burst cast. So I just wanted to follow up on Amit’s introduction. I think one of the things that goes wrong as we get older that is silent is that our immune system stops functioning as well. And you can't tell this is happening until you're an older adult and get a respiratory tract infection. And we've known for decades that respiratory tract infections are much more severe in older adults. They're more likely to get hospitalized or have very prolonged symptoms, more likely to die. These infections re and we've seen this in COVID. It became very obvious to everyone. And that's happening because the immune system has been declining in function for probably decades and we aren't seeing it until we get that infection. and we're treating I'm just going to focus on viral respiratory tract infections because they're the most common infections that older adults get. They're caused by hundreds of different viruses. So, for instance, this winter has been a very bad cold and flu season in the US and people are getting really sick but having negative flu and COVID tests. And it's because the viruses that are circulating and making everyone so sick probably aren't flu and COVID. it's one of these other hundred. And so you can't really tackle this by going after one virus at a time with a vaccine. It's great we can do it for some viruses, but another approach would be to say, what can we do to build up the function of that aging immune system so that it is more resilient and it functions more like a young immune system when we get a respiratory virus. And this is kind of getting to Amit's point. instead of waiting till that older adult gets really sick, could we just start and prevent them from getting sick by focusing on improving immune function? So, this was a area, you know, I'm an infectious disease doctor that was near and dear to my heart and sort of underlies my approach in this field.

8:33 Joan Mannick

But then the question is how do you improve the function of the aging immune system? And this was a question that I was asked at Novartis. I joined Novartis in 2010 and was tasked with figuring out how we might be able to improve target aging in humans. And the most obvious way to do this, Julia, you mentioned, was by targeting a single protein called mTOR. And the reason this protein is so interesting is if you inhibit it, as Julia said, in every species studied to date, yeast, worms, flies, and mice, lifespan is extended. And not only do these organisms live longer, they stay healthier longer. And it's remarkable because these species span a billion years of evolution. So it is quite likely, this is so evolutionarily conserved, it's quite likely that inhibiting this one protein will have some sort of benefit for human aging as well. And it's also remarkable because there are maybe 10,000 proteins expressed in a mouse. So how does inhibiting one protein have such dramatic ex effects on lifespan and health span? It's just remarkable. So at Novartis I had to figure out they actually had an inhibitor of this protein and I had to figure out well how can we tell if this inhibiting this protein in a human has benefits on human aging because it occur aging occurs over decades. You can't measure lifespan. So, how can you tell in a relatively small clinical trial whether a drug targeting fundamental aging biology as mTOR seems to do, how do we tell if that's helping a human? So, if you want to go to the next slide, Julia, and please jump in with any questions. So we thought about okay we can't look at lifespan but in aging mice the function of some aging organ systems but not all get better. So the function of the brain aging brain gets better. We want to make sure this was reproduced by multiple groups and it was the function of the aging heart gets better. That's also re reproducible.

11:06 Joan Mannick

physical activity of older mice. They get have they stay more active and they have better immune function as assessed by responses to vaccinations. So looking at these different organ systems, the key one that we thought we could study in a relatively short period of time was the immune system because the immune system you can change the function of the immune system in a relatively short period of time. So to get a quick look at whether any of this aging biology that was seen in pre-clinical species actually translated to humans, we could take a quick look by seeing can an mTOR inhibitor improve the function of the aging immune system. And as I've outlined, if we could do that, that could have a huge effect on morbidity and mortality in older adults because infectious diseases do cause a lot of morbidity and mortality.

12:09 · Duration of effects and the first vaccine study

12:09 Amit Agrawal

So when we are talking about slowing down or restoring the immunity, how long this this will last after the treatment? Will it disappear or we can keep reviving it after each dose?

12:26 Joan Mannick

So we didn't know what was and in the mice that were shown to have improved immune function that was not studied. But what was studied which was interesting is in the studies where an mTOR inhibitor enhanced for instance the response to a flu vaccine in older mice and they just gave six weeks of the mTOR inhibitor rapamycin to the old mice. So they respond better to a flu vaccine, but they also lived longer. So even though they were only given six weeks of rapamycin when they were old, this seemed to have some sort of persistent benefit that extended lifespan.

13:08 Joan Mannick

That was a small study, but that's been reproduced by Matt Kaeberlein and some others in subsequent studies showing at least for lifespan there is some sort of persistent benefit of rapamycin an mTOR inhibitor and it suggests something is getting reset that persists after even a short course of an mTOR inhibitor and we don't yet know what that is.

13:36 Julia Majewska

So do you have insights into inflammation level of inflammation inflammaging and mTOR inhibition?

13:46 Joan Mannick

Yes. So to the first trial we designed again we wanted to just you when you're doing clinical trials you don't you want to do small clinical trials initially to see if there's a real signal that you're on the right track and that your drug is likely to work because if you start with a huge clinical trial you can just they're very risky when you're trying something new and there are hundreds of millions of dollars when they're large. So, you want to figure out a way without having to spend hundreds of millions of dollars, is your drug likely to work.

14:26 Joan Mannick

So when I started this at Novartis, I said, let's just see if an mTOR inhibitor can improve a flu vaccination response in older adults because without having to follow hundreds of people for months, you can see whether someone's responding to a flu vaccine in 4 weeks. So we just reproduced in humans a study that had done in old mice. So in older adults, we gave them six weeks of an mTOR inhibitor and then we gave them a flu vaccine and then four weeks later we looked did you have a better response to a flu vaccine or not?

15:06 Joan Mannick

And this was a risky study that and I actually got a fair amount of push back at Novartis because mTOR inhibitors are normally used to suppress immune function in transplant patients and very high doses are used that will stop T cells a key immune cell type from proliferating. So we decided and lots of people at Novartis went into figuring out what doses we should use which we were predicted would be very safe. They're much lower doses than are used in transplant patients. Very safe and were going to be too low a dose to suppress immune function. So we used very low dose daily mTOR inhibitor or once weekly mTOR inhibitors. So very different than the doses that are used in organ transplant patients and also in cancer patients. And what we found is these very low doses or intermittent doses of m of an mTOR inhibitor were actually well tolerated. That was a big deal because everyone thought maybe all that science aging biology in preclinical species wouldn't translate to humans because it was too dangerous to inhibit mTOR. So we showed yes, you can safely inhibit this protein in humans. And remarkably, flu vaccine response got better. And that was a big deal because it was the first evidence that all of this basic science that was so profound of lifespan and health span extension might actually translate to humans because at least the function of one aging organ system was improved by an mTOR inhibitor. It was just the first step. There's a lot more that we need to prove but first step it looked good.

16:58 · Vaccine responses and infection measurements

16:58 Julia Majewska

So Joan when you are talking about improved vaccine response what do you mean specifically increased antibody titers or exactly lack of infection of this patients who got the who got the drug right?

17:14 Joan Mannick

So for flu vaccine you measure efficacy by looking at the antibody titers. To look at infection rates you need thousands of people because not that many people get the flu. But to look at infection just to look at did your antibody titers to that flu antigen that's inside the vaccine were they boosted and they were. So the people who got the flu vaccine had higher antibody responses when they got an mTOR inhibitor versus placebo. So part of what you do in a clinical trial is you collect adverse events and you have people who are in the clinical trial just report every single time something untoward happens to them whether it's related to the drug or not. So, you know, they can report getting a headache, falling down the stairs, getting a runny nose. And when we looked at the adverse events that were happening in people who got an mTOR inhibitor versus placebo, we saw that people who got an mTOR inhibitor were reporting having fewer respiratory tract infections. And they weren't flu, they were just all-comer respiratory tract infections like colds. And that gave us a signal that maybe the mTOR inhibitors weren't just improving the response to a flu antigen. They were having more broad benefits on the immune system and helping people respond to all sorts of respiratory viruses. We then did a second trial. We repeated the same thing. We gave older adults six weeks of an mTOR inhibitor.

18:58 Joan Mannick

We looked to see if we could reproduce that boost in flu vaccine response. But this time we also prospectively looked at asked them to report how many times they got an infection and how many times they got a respiratory tract infection. And then we also wanted to get a sense of why are people who have gotten an mTOR inhibitor responding better to the to a vaccination? what's happening to gene expression in their blood where the immune you know their immune cells and so we did what's called non-hypothesis driven RNA-seq we didn't look for any particular genes we just said what are all the genes that change in expression and the blood of people who get an mTOR inhibitor versus what are all the genes that change in expression in people who get placebo and are there any differences because those differences might tell us what is the mTOR inhibitor doing to make immune function better. So what we found in that study is again the mTOR inhibitor improved the vaccine response and then more exciting people got the mTOR inhibitor had fewer infections and most of the infections were respiratory tract infections. They are of course the most common infections people get and those were significantly decreased. And then what was really interesting is when we looked at the gene expression changes in people got mTOR inhibitors.

20:33 Joan Mannick

The genes that were most significantly upregulated were critical genes that the immune system uses to fight viruses. And now the story was sort of falling together. So what it looked like and this was completely unexpected. This hadn't ever been described in a mouse or a yeast or a worm. What mTOR inhibitors seem to be doing in older adults was boosting their antiviral response. And this is a response that gets defective as we get older and one of the reasons why we get more severe respiratory viral infections as we get older. So we thought, well great, maybe we could use an mTOR inhibitor to boost the function of the aging immune system, particularly the antiviral function, and protect older adults from getting a respiratory tract infection during winter cold and flu season. And this would be a completely novel thing. And it gets again to what Amit was saying instead of waiting for them to get sick, you know, waiting for that hit to that sort of challenge to their immune system that they failed to meet will boost the immune system. So

21:48 · Immune cells and mechanistic questions

21:48 Joan Mannick

when they get that virus, whatever it is, they'll be able to fight it effectively.

21:48 Amit Agrawal

It's it's a great phenotype. This is what matters at end of the day whether people are able to fight virus or cancer or not. But I'm just trying to understand the mechanism. Did you look at the immune profile? How which immune cells increased decreased and what happened with their function and how mTOR was doing that?

22:09 Joan Mannick

Yes, we did extensive immune profiling in both studies more in the first study and it was interesting. It doesn't have a big effect on most immune the number of immune cells. The ones that the two where there were significant decreases were PD1 positive CD4 and CD8s go down with an mTOR inhibitor and this is subsequently also been shown in shown in older mice. So there's fewer exhausted T cells and that may also be one of the reasons why people can respond their immune function is responding better. But other than that, you know, there weren't we thought maybe there'll be more regulatory T cells or fewer regulatory T cells, but we didn't really see because I think these are very low doses. we didn't see a lot of shifts in immune the numbers of immune cells and that you know there weren't big increases in naive T cells for instance we didn't unfortunately look at function we actually had samples that we had collected to look at immune function and they were shipped to Europe unfortunately on dry ice instead of liquid nitrogen and there was some delay and the dry ice melted and we lost all the samples in the first study which was tragic because it's so hard you know it's millions of dollars to do these studies and the samples were lost. So that is a deficit we have that we don't understand functional we haven't tested yet functional consequences in these older adults.

23:50 Julia Majewska

So Joan can you explain why do you think that the level of PD1 positive population CD4 or CD8 cells were decreased?

24:09 Joan Mannick

Yeah, we don't know yet either. You know, I think in Tyler Curiel has seen the same thing in old mice and is, you know, investigating the mechanism, but it's still not clear what's happening and why though those those T- cell exhausted T cells are decreasing in number

24:32 · Respiratory infection trials and inflammation

24:32 Julia Majewska

and in the studies have you seen also reduced inflammatory profile in the serum of these patients or

24:40 Joan Mannick

Yes. So let me go to the next study because we looked at inflammatory cytokines in the next study. So we then said let's treat older adults for 16 weeks during the peak of winter cold and flu season and let's see if we can decrease the incidence of respiratory tract infections. And in this study, we enrolled patients who were at increased risk of getting really sick from winter colds and flu. So those were people who were over 85 or with diabetes or with COPD or current smokers and all over the age of 65. And we treated them for winter in during winter cold and flu season and we saw a significant decrease in the incidence of respiratory tract infections and again we saw a boost in their antiviral gene expression. So again, this is repeating over and over. Decreased res incidence of respiratory tract infections, whether it's just self-reported as an adverse event or prospectively captured. And in this one, we actually did nasopharyngeal swabs to make sure that we these were infections that they were reporting. We were confirming it by showing that there was a viral infection happening. And in this study, we got inflammatory cytokine profiling done. So those are proteins in serum, not just gene expression. And of interest, the inflammatory cytokines go down in people who aren't infected. So you sort of get a reduction in inflammaging and then in people who get infected, you get a better boost in that inflammatory response.

26:44 Joan Mannick

So it was really interesting. It looks like what mTOR inhibitors might be doing is sort of dampening down the basal level of inflammation which should be quite good for organ systems and that also allows a better response once you get an inflammatory new signal. When you sort of stop that chronic low-level activation you can activate better. So after this study,

27:13 · Choosing the phase 3 endpoint

27:13 Joan Mannick

we went to the FDA and said, you know, we'd like to do a phase three study and those that's the study you need to get a drug approved. And they said to us, look, this is new to us. We have never developed a drug to improve the immune system and fight any kind of respiratory virus. But we've changed our mind. In the phase 2 B study, we wanted you to do these nasopharyngeal swabs to prove that people have a real infection and that you're really stopping infections. And they said this was right before COVID they said in the real world no one gets a nasopharyngeal swab and since we are wanting to approve this for the real world we no longer want you to do for your primary endpoint a nasopharyngeal swab. What people care about are their symptoms. So you have to show us that you can decrease the incidence of respiratory symptoms, not respiratory tract infections. This and we said please please we don't we don't think we're going to decrease just any old respiratory symptom. We're only going to decrease those that are caused by infections. And they said, 'Well, just figure out some symptoms that are most likely to be due to infection and show that you can reduce those. Well, this turned out to be really complicated because older adults get all sorts of respiratory symptoms even when they're not having a respiratory tract infection.

28:53 Joan Mannick

And so in the trial, people were coming in and meeting our criteria for having respiratory tract infection symptoms when they knew they come to their to the investigators in the trial and say, "I know I don't have a cold. These are not due to an infection. I know I'm not infected, but they were hitting the definition of our end point." So, you know, in it was interesting in the this was the first big phase three trial targeting aging biology. And I think a lot of people in the field thought, oh my gosh, if this trial fails, you know, the whole field it just everyone's going to think targeting aging biology doesn't work. But the truth was, you know, it was our first step, got the end point wrong, unfortunately, but there was tremendous amount that we learned from this that I'm hoping other people can learn from and also target, you know, not necessarily even with an mTOR inhibitor, although I think we should keep moving forward with mTOR inhibitors for this indication. I think all sorts of drugs targeting aging biology can be used for this kind of indication to boost immune function in older adults. So what were some of the lessons learned?

30:13 Joan Mannick

So one of the most interesting things that we learned and this even in the phase three trial mTOR inhibitors boost antiviral gene expression. So for people who aren't familiar with this kind of graph, this is a graph called a volcano plot that shows what genes are most upregulated and what genes are most downregulated in the blood of people getting an mTOR inhibitor. And so the green the pink dot if you if if you take zero any of the dots that are to the right are upregulated and any of the dots to the left are downregulated. And the green dots are the dots the genes that are significantly upregulated. So when you look at all the genes that are sort of to the right and the more significant the upregulation the higher they are on that plot and all those genes that are highlighted with the black rectangles those are antiviral genes.

31:17 Joan Mannick

So you can see a lot a lot of the genes that are shifting in older adults getting an mTOR inhibitor are antiviral genes. These are genes that are the first line of defense we have against viruses and their upregulation is defective in older adults and that's one of the reasons again that they get more severe viral respiratory tract infections. What was so interesting about this is this had never been seen in a yeast, a worm, a fly, or a mouse. And that is the beauty of doing clinical trials in humans is that you see biology that you don't necessarily see in pre-clinical species. And I always I love doing clinical research because you get to see this data. You get to see what we really care about, which is what happens in a human and how can we help a human? Yeah, we were assuming we were going to see upregulation of autophagy genes or mitochondrial biogenesis genes, but no, it's really antiviral gene. The other thing we learned is probably even if we

32:28 · Trial results and exploratory interpretations

32:28 Joan Mannick

had a endpoint in the phase three trial that was infections, not just symptoms, we probably weren't getting the right endpoint. So I'm just going to show you in the big trials that we did the phase 2b which was in 600 patients I think and the phase three which is in a thousand patients. So these are big trials done in elderly people. If you look at just the incidence of how many people got a respiratory tract infection of any severity, you got a significant 31% decrease in the phase 2b and people got an mTOR inhibitor and you only got a trend. That's why the trial failed in the phase three. Now the phase three it turned out not only did we have a weird end point but that cold and flu season which was the year before the COVID pandemic was a really mild cold and flu season. So the incidence of respiratory tract infections was half what had been during the phase 2b. So we're actually underpowered in this trial. So the drug still may have worked, but when you have a trial that's too small, you can't hit statistical significance. But then if you look at this incidence of severe respiratory tract infections, you starting to see a bigger treatment effect in both trials. A 52% decrease in the phase 2b that was significant and a 29% in the phase three. Even the failed phase three and again not significant trial was underpowered. You're seeing this trend. There seems to be a greater effect on severity of the respiratory tract infections than just incidence. What we really care about is stopping no stopping hospitalizations. Those are the really bad infections. The numbers are too few, but it's consistently the biggest treatment effect. a 74% decrease in a hospitalization for respiratory tract infections in the phase 2b, 50% in the phase 3. You know, the numbers are too small. This could all just be a fluke. But that's looking like what mTOR inhibitors really may be more effective at is decreasing severity of infection than decreasing incidence. Why might that be the case? Well, we've done more basic science studies since doing these trials and what the preliminary data is looking like is that the mTOR inhibitors are not increasing basal antiviral gene expression. It's not until the immune system sees that virus that the mTOR inhibitor boosts the antiviral response. So, you still can get the respiratory tract infection. you haven't upregulated the antiviral immune response yet, but as soon as you get it, you'll get a better immune response to that virus and decrease the severity of the infection. We think that's what's going on. So going forward, we think that people should look at severity of infections, hospitalization for infections rather than incidence. And then so

35:50 · Severity versus incidence

35:50 Julia Majewska

Joan so from exactly what you said from public health perspective it would be better to look at severity of disease like hospitalization or severe disease outcome onset rather than incidence. So would it be possible to change the end point for phase three clinical trial?

36:16 Joan Mannick

Absolutely. Absolutely.

36:16 Julia Majewska

minimize the noise of any symptoms that can be due to thousands of factors or you still

36:24 Joan Mannick

it's and this the same thing happens with a covid vaccine. You still may get COVID but your the severity is going to be reduced. My hypothesis that h you can never say this is true till you do the big phase three trials is that in older adults the mTOR inhibitors you still may get your cold you still may get your flu you still may get COVID but its severity will be reduced it'll be less severe symptoms duration will be shorter and you're less likely to get hospitalized so one more lesson learned that I think is important for the field. One of the things that

37:06 · Age, biomarkers and participant selection

37:06 Joan Mannick

we're doing right now is just defining old as 65 and above. And what we learn from these trials is one 65-year-old is not the same as another is not the same as another. And I think in the aging field as we go to the clinic, it's going to be really important to do more personalized medicine that you can't just it's going to be too noisy to just take everyone who's 65 and assume that they have some sort of aging related deficit. And I think this is true for the immune system. So in these trials and again this is you know over a thousand people studied the biggest treatment effect always seems to be in the older adult population not the sort of 65 to 75 year old I think a lot of 65 to 75 year olds have normal immune systems they are still at their ceiling they're not really having trouble with COVID or having trouble with flu. But starting around 75, I think then there's a more homogeneous decline happening. So in the here's data from the phase two the phase 2b study. And in that study, we prospectively looked at people who are over 85 and compared their response to people under 85. And you can see here the percent of subjects who got a respiratory tract infection in people over 85 treated with placebo in the dark green was about 45%. So a lot of over 85s get infections. But when the people got an mTOR inhibitor that was decreased to 15%. So there was a 2/3 reduction in the incidence of respiratory tract infections in the over 85s. where if you look at the younger under 85 population, it was only about 20%. So really, you know, we don't have a biomarker yet of who has a def immune defect in their antiviral response. That would be great if we had it, but a way we could stratify right now is to go say if you're over 85, you are probably the one at risk. You are the one we should target.

39:35 · Inflammation and conflicting observations

39:35 Julia Majewska

I what you just said we don't have good biomarker up to now which thanks to which we would be able to stratify patients how they would respond to the treatment but so it looks like that mTOR inhibition is more effective in more elderly patients and do you think it could be due to increased inflammation level or the more inflammation level that is associated with impaired immune function. So the more impaired function you have the more effective mTOR inhibition would be

40:18 Joan Mannick

I would have thought so you know I had that same hypothesis the funny thing we saw and we've never published this is that pe the people at bas forget the mTOR inhibitor the people who had increased inflammatory cytokines at baseline seem to have fewer respiratory tract infections than the ones who had decreased

40:46 Joan Mannick / Julia Majewska

inflammatory cytokines and that may and again can you repeat people who have really counterintuitive

40:54 Joan Mannick

and I don't know why and again this has to be repeated but if you look at people who have sort of increased inflammaging based on sort of increased levels of IL-6 and IL-12 versus those who don't the people who have increased levels actually had fewer respiratory tract infections than the people who had lower levels. And it suggested why do we have inflammaging? Maybe we have inflammaging because it's a defense against viral respiratory tract infections. You know, our system is kind of on all the time. That doesn't fit with the fact that mTOR inhibitors decreased inflammation and allowed a better response. So, I can't put those two together. But what I'd say is I don't know because of those conflicting pieces of data. Is it really that because the mTOR inhibitor suppressed inflammation which might be quite good for other organ systems but maybe not for fighting infections but whatever it did it did something else in addition that allowed a better response to respiratory viruses. M so very right conflicting data and I don't know your your

42:14 · Immune aging across organ systems

42:14 Joan Mannick

question is great and I don't know the answer

42:14 Julia Majewska

it's very interesting do you think that we need higher resolution exactly targeting particular immune cell types to understand which immune cell type is primary giving given phenotype or somehow to be able to link it.

42:31 Joan Mannick

I think this is the most probably important area of aging biology because you know I'm looking at the obvious thing which is you improve immune function you get fewer infections and it's just answering why is the mTOR inhibitor helping? It's complicated. It's fascinating. We need to do the studies that you're saying. We need to do develop biomarkers to figure out who's got defective immune function and who doesn't. I mean there's so much to do and it's so important and going to be you know could be transformational for public health particularly with an you know the next pandemic whenever it's happening. But it's also so important because the immune system when it age, it ages affects all aging organ systems and probably contributes to why all other organ systems age. And we're increasingly, you know, starting to understand the cell non-autonomous effects of immune cells. So immune cells are going everywhere in the body, the brain, the heart, the kidney, and when they get dysfunctional, they damage all these other organ systems. And there's an import really important paper from Laura Niedernhofer. It was published in Nature a few years ago showing if she just ages the immune system, all the or multiple other organ systems start to age. So, it's such a complicated system and it's such a critical system for aging and it's a system that we can easily target. You know, it's easy to get a drug to get to immune cells unlike inside a muscle or inside the brain. And by targeting those immune cells, we still may be able to have profound effects on the function of the brain or the function of the muscle. So it's I love this field and it's nent there's so much we still need to work on and to understand.

44:48 Amit Agrawal

We also published on the similar lines one paper where we showed that if you have a in a perforin knockout mouse like you they accumulate much faster senescent cells those are SA-β-gal-positive cells in different organs. So, so, so immune system is certainly playing a very strong role,

45:10 Joan Mannick

right? You need your immune system to clear senescent cells. So, I mean so many you need your immune system to fight the cancer cells, you know, it just goes on and on the like and everyone develops drugs like you look at pharma, they develop drugs for the aging brain. Everybody's trying to get Alzheimer's. Great. the aging heart, heart failure drugs, aging bones, osteoporosis drugs. No one has been targeting let's develop drugs for the aging immune system. It's like an untapped area that has that's going to have profound benefits. I suspect when this area really gets some attention and focus. Just to show in the

46:01 · Older participants and the small COVID study

46:01 Joan Mannick

phase three, we didn't have enough people 85 and above. So we looked at 75 and above versus 75 less than 75. And again, this is the study that didn't hit its end point, but if you look, there's a 43% decrease in respiratory tract infections in the over 75s and almost no decrease in the under 75s. So going forward, you know, cracking this tough nut to crack, I'd say we really need to focus on the 75 and older. Those are the people my guess is because they that's when immune function is really starting to decline. So you're getting a more homogeneous group that needs a boost. Those are where we should focus our efforts. And it's also interesting. There's been epidemiologic studies looking at when people die during the year. And when you're under 75, whether you winter, spring, summer, the death rate is all the same. And starting from 75 and above, all of a sudden there's peaks of death during winter cold and flu season. And I think it's because what we're seeing here, something that group is where immune function is really starting to decline and they can't handle the respiratory viruses. They're more severe. And when you get a respiratory tract infection, it exacerbates all sorts of underlying comorbidities and you get these peaks and all cause mortality. So with that lesson learned, we said, okay, we did one last trial after that phase three and it was during the COVID pandemic and we said, let's test this hypothesis.

47:47 Joan Mannick

If we only enroll very old people and we look at severity of a respiratory tract infection, not incidence, doesn't look like that endpoint might work. And so what we did is this was before COVID vaccines were available and all nursing homes were under lockdown. It was really hard to do this study because it was such a zoo. You know, it the nursing homes were under such siege. But we got a few nursing homes to say we'll either give pe if there's a nurse if there's a COVID outbreak in our nursing home, we'll randomize people who haven't yet got COVID to either get an mTOR inhibitor or placebo for 4 weeks. And let's see, do the people who have get the mTOR inhibitor have fewer severe respiratory COVID infections? And here was the result in people during the COVID outbreak who got placebo. Sorry, a number is missing. It's four out of 17. So again, small numbers. About 24% got severe COVID and half of them died. And of the people who got the mTOR inhibitor, none of them even got a symptom of COVID, let alone a severe infection. Just nothing. this when you have a small trial like this could just be random but it's a signal that we're getting to the right place that if we look at a old population 75 and above and if we look at severity that mTOR inhibitors might be quite effective but again this has to be proven in a big trial but it's

49:24 · Dose, safety and partial inhibition

49:24 Joan Mannick

promising

49:24 Julia Majewska

great u Joan you are mentioning here that these patients were treated with low dose of mTOR inhibitor. So could you a little bit explain us what does it mean? whether you've seen any differences with higher dosage or why did you target lower dosage of mTOR inhibitors specifically? could you could you could we have your opinion on that?

49:49 Joan Mannick

So when we first started the study way back that first vaccination study everybody in the field was saying you can't treat this one drug called rapamycin I should step back one drug in every species extended lifespan but everyone said you cannot use rapamycin in older adults cuz it's not safe Why were they saying it wasn't safe? because rapamycin is approved to treat prevent organ transplant rejection and at the doses that are used it has a lot of side effects. It has GI side effects. It causes mouth ulcers. It can suppress the number of immune cells and it certainly suppresses immune function because that's how it works to suppress the immune system from rejecting an organ. So we said well if this is going to work clearly we can't use doses the usual dose of mTOR inhibitors rapamycin like drugs because it wouldn't be safe so we have to see if this could work at safe doses and we also thought with age mTOR in the whole signaling pathway the mTOR activity gets hyperactivated in multiple organ systems. s and it's supposed to be on when you eat and off when you fast, but what happens is it just stays on all the time and never gets suppressed with fasting. So we said, "What if we just turn mTOR down?" And with in transplant patients, you want to turn it off. Just use low doses that turn it down to young levels. That should be safe. and maybe that will be effective because it's we're retuning the system to a younger level. So the fortunate thing working in big companies like Novartis is they have armies of people to help you. So I had these fabulous modeling and simulation teams that modeled what dose of an of their mTOR inhibitor would we need to just turn down mTOR not turn it off. And in that first study, we tried several different doses predicted to give different levels of mTOR inhibitor. So one suppressed 80%, one 50% and one 40%. And it turned out the 40 and 50% inhibition led to the improvement in immune function, whereas the 80% was less effective. So you know again this isn't perfect because you there's no good biomarker of mTOR inhibition in accessible tissues in humans but by modeling and simulation it looks like partial inhibition is what is best.

52:56 Julia Majewska

So it sounds like you need to find really the sweet spot in terms of dosage of mTOR inhibitor to have the beneficial effect. And another questions how

53:14 · Persistence of effects and variability

53:14 Julia Majewska

long how longterm are these effects if you treat the patients of mTOR inhibitor and it helps to prevent severity of respiratory tract infections for how long these patients are being protected does

53:29 Joan Mannick

it's a great question we've only looked at this once in the second trial and What the design of that trial was after they finished the six weeks of mTOR inhibitor where we really closely followed how often they were having respiratory tract infections. Not only did they have to write it down but we asked the study coordinators to call them once a week so that no one was forgetting. After that once a month during the whole the next year they were supposed to fill out their diaries if they had a infection and once a month the coordinators will call them. So it wasn't perfect collection of data because you know when you're did they remember to fill out their diary when they're called once a month were they remembering what whether they were sick the previous month. But when you looked over the entire year, the people were reporting who had mTOR inhibitor were reporting fewer infections for an entire year even though they had only gotten six weeks of the mTOR inhibitor. It's an imperfect data set. So I don't want to say ah that's for sure it the effect is prolonged but there is a signal that like in a mouse where a short course of an mTOR inhibitor seems to have prolonged effects that extend lifespan. This looked like there was some sort of persistent resetting of the immune system that persisted beyond the six weeks.

55:07 Joan Mannick

But this has to be repeated in more rigorous studies that really compulsively follow people for a year.

55:14 Amit Agrawal

we have worked extensively on the old mice, naturally aged mice. We induced senescent cell using DNA damage drug called bleomycin in the lung. And what we saw that old lungs are more vulnerable for the DNA damage comparing to young lung. But senescent cell that formed in young versus old the variance in young in the percentage of senescent cell was very small comparing to old. So there is a huge variance across as we age the variance increases and it's very difficult to do clinical trials on the old humans because of the variance. So in your case you are saying that it can be done much more personalized if we have a way to measure who has a less immunity.

56:11 Amit Agrawal

Exactly some immunity score but this is one thing that we are talking about immun score but there are so many other things that we will we don't know what we need to measure. We are looking at one metric but there might be many heterogeneity underlying and we may ignore that failure or missing out the real positive effect of drug. How do you make how do you make sure that your drug that your that is going in clinical trial will not will not fail just because we end up missing the right signal.

56:40 Joan Mannick

You know, it's a great question and I don't think right now, you know, these studies, the big ones were done, you know, the COVID one was done in 2019 and the readout of uh maybe it was 2020, the readout of the phase 3 was 2019 and there weren't ways at that time, even though we got a lot of proteomics and transcriptomics, there wasn't anything that was really distinguishing who was a responder and who isn't. I think we've come along you know with all as you say the different immune aging biomarkers we could see do they predict or not but for this particular indication I just think it's fortuitous that somehow the 75 and olders have enough homogeneity in this their immune function that even though it's noisy we probably will be able to and this remains remains to be seen. probably be able to develop a therapy just based on age as a you know as a sort of narrowing the inclusion criteria but it will be even I think for most indications you're right one old if you've seen one old person you've seen one old person because they're all so different so I think we really even with an mTOR inhibitor are going to need to stratify I and do some basic science to understand you know what are the genetics what are the transcriptomics that predict response to an mTOR inhibitor and start in pre-clinical species and then test in the clinic it's a lot needs to be done and understood

58:37 · Sex differences and future research

58:37 Julia Majewska

so following on that question have you seen any effect of sexual dimorphism in mTOR inhibition and you know its effect different efficiency in preventing severity of disease in women versus men

58:56 Joan Mannick

not for the immune system which was surprising the men and the women are responding the same but based on the mouse data I would suspect and some other indications there will be differences between males and females and there'll be an interaction with sex in terms of treatment response.

59:24 Julia Majewska

So what would you be your prediction? female would be better responders or

59:24 Joan Mannick

I suspect there's going to be a the sex difference is going to depend on what you're targeting whether it's going to be better for males or better for females. So I think it's too early to say, but I've seen some data that's confidential where the effect looks better in the males and some where it looks better in the females and it's genotype dependent. So it's it's really interesting. It's not one size fits all and it's where the field is should be going, you know, really targeting. There's going to be specific sex specific genotype specific probably transcriptomic specific populations that need to be enriched that will be the responders to all sorts of aging therapies is just my prediction and I could be totally wrong but from the data I've seen so far that's what I

1:00:35 · Future directions and regulation

1:00:35 Joan Mannick

would predict.

1:00:35 Julia Majewska

Sure. Thank you. Thank you so much.

1:00:35 Amit Agrawal

Say if the anti-aging these drugs work and other drugs work like what kind of future we can imagine how the old age will look like 10 years from now.

1:00:55 Joan Mannick

I think we'll keep people healthier longer. I think this is so feasible. I mean I think we're really close and I'm not even working on mTOR inhibitors and aging right now. I've I'm at Altos Labs where this isn't the focus currently, but I think we've gotten really close and I hope someone else brings the mTOR inhibitors forward for this indication. It's close. the end points need to be tweaked, but I'm pretty feel pretty good and I could be wrong. But I think what we're going to be able to do is prevent disease as you were talking about at the beginning. I think so many diseases that manifest late in life are actually diseases of middle life, midlife like Alzheimer's.

1:01:49 Joan Mannick

All the pathology of Alzheimer's is happening in midlife and it's just silent and it just doesn't clinically show itself till you're late in life. And if we can develop start as the aging field targeting those things that are happening before people get sick and demented or infected or have their heart attack or break their bones. you know, we've got there with osteoporosis, we're building up bones. If we can do that with other organ systems, you know, it'll be very effective at keeping people healthier. And I think this is going to require new some changes. The main thing stopping this is the regulatory system. And it's not that the regulatory system needs to say aging is a disease. That's not the problem. The problem is if you start treating something years before a clinical manifestation, you can't wait for the decades before there's a clinical manifestation to have your clinical trial endpoint because that is economically not feasible to do that trial. So we have to get the FDA or health authorities around the world to go for things that we have a good shot of preventing diseases. We have to be able to accept some sort of surrogate endpoint that may not be totally proven to the rigor that is currently required, but there's sufficient evidence that this is likely to translate to benefit later on that we're willing to approve that drug. That's what's missing right now.

1:03:40 Joan Mannick

It's just fundamental for all this biology to really impact human health span. I'm not sure if that makes sense to non-drug developers. It's just so and there's someone named Alexander Fleming who has tons of experience at the FDA. He led their whole endocrine division and was the person responsible for metformin approval and the first statin approval. He understands this and he has put together legislation called the Thrive Act that he's going to at some point present to Congress and see if we can get this passed to be able to approve drugs that are targeting, you know, preventing disease, targeting aging biology, keeping health span, whether we can have a different regulatory path. It's just so important what he's doing.

1:04:43 Amit Agrawal

We really need these initiatives because otherwise many anti-aging companies or companies who are doing who are basically developing something to prevent age associated diseases will keep drifting to rather than prevention or reversing treating and that we have seen now actually in the market so many anti-aging startups now they are more moved to curing a particular pathology than systemically preventing certain

1:05:08 Joan Mannick

Right, which is just drug development 101 really. It's like we're missing where our whole field could have transformational impact which is that targeting before the disease occurs. the manifestation is occurring but the abnormality is there like we're not we don't have a regulatory way to get that kind of thing approved and so we can't get funding because if you can't get a drug approved then investors can't invest unless they're philanthropic because they can never get a return on investment. So

1:05:54 · Closing

1:05:54 Joan Mannick

this is just fundamentally important.

1:05:54 Amit Agrawal

So we conclude our session and thank you

1:06:07 Amit Agrawal / Joan Mannick

Joan Sure for sharing with us the cutting edge you bet clinical trial data and showing us

1:06:18 Amit Agrawal

the reality of translating the fundamental aging research into human clinical trial.

1:06:30 Joan Mannick

Yes, I it's been a pleasure. Thanks for having me.

1:06:35 Julia Majewska

Thank you. Thank you very much. This truly inspiring

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