#118 – Lloyd Klickstein, M.D., Ph.D.: Rapamycin, mTOR inhibition, and the biology of aging

1. 0:00 – 6:15

   Intro

   1. PAPeter Attia0:01

      [upbeat music] Hey, everyone. Welcome to "The Drive" podcast. I'm your host, Peter Attia. This podcast, my website, and my weekly newsletter all focus on the goal of translating the science of longevity into something accessible for everyone. Our goal is to provide the best content in health and wellness, full stop, and we've assembled a great team of analysts to make this happen. If you enjoy this podcast, we've created a membership program that brings you far more in-depth content if you want to take your knowledge of this space to the next level. At the end of this episode, I'll explain what those benefits are, or if you want to learn more now, head over to peterattiamd.com/subscribe. Now, without further delay, here's today's episode. My guest this week is Lloyd Klickstein. Lloyd's the chief scientific officer at resTORbio, so that's little R-E-S, big T-O-R, little B-I-O. Get it? TOR, T-O-R. resTORbio is a clinical stage biopharm company that develops meds that are primarily aimed at targeting TOR, targeted rapamycin. We'll talk a lot about that throughout this episode. So prior to joining resTORbio, Lloyd was the global head of translational medicine for the new indication discovery unit at Novartis. And prior to that, he was an academic physician at the Brigham and Women's Hospital, which is one of the flagship programs at Harvard. Lloyd received his bachelor's from Tufts and an M.D. Ph.D. from Harvard. He's got more accolades than you could shake a stick at. So accolades aside, the reason I wanted to speak with Lloyd was because he is really one of the few people on this planet that has a really nuanced understanding of the clinical application of rapamycin and rapalogs, and we talk a lot about one of them in particular called everolimus. Lloyd was the senior author on a paper that I have spoken about many times on this podcast, which we'll go into in great detail here, a December 2014 paper. Joan Manick was the lead author on that paper, and that was the study that was basically the turning point in my personal evolution or thinking when it came to the use of rapamycin for the purpose of longevity. Prior to that, there had been a lot of studies that had certainly suggested in animal models that rapamycin could be a true longevity agent, but it was the Manick Klickstein paper of December 2014 that was the real turning point in my thinking. And that's really where we're going in this discussion, along with talking about all that's been done since then. It is important before we start this interview that I mention, of course, that Lloyd is an employee of resTORbio. resTORbio is a for-profit company that is working on mTOR inhibition, so please caveat everything that we discuss through that lens. Before this podcast begins, I want to note that we recorded this interview in September 2019. Now, in the interview, we discussed an upcoming phase III trial from resTORbio. Since that time, the results have been published and the study did not meet its primary endpoint. Now, I frankly left the option to Lloyd as to whether or not he wanted to still have the podcast air, and he felt that that would be fine to do. And so we're going to go ahead with it. And eventually, I'm going to be interviewing his colleague, Joan Manick, along with Nir Barzilai. I'm going to have the two of them back on an episode where we're going to discuss a whole bunch of things that'll be quite interesting. And this gets more complicated because I think I have a pretty clear understanding of why that study failed and what it does and doesn't say about selective inhibition of agents like it. Nevertheless, I think the most logical thing to do is to go ahead and proceed with this interview, which is one of my favorite interviews on this subject matter, and just know that there are going to be a number of things that are left as open-ended questions from this discussion that we're going to pick back up with Joan Manick when we do that interview, which I'm scheduled to do a few weeks from now. And hopefully, we'll try to get that one out at a much quicker turnaround. There were a number of issues that delayed the release of this, not the least of which being some of the COVID stuff. But, uh, I can promise you that there will be a shorter gap between when you are hearing this and you will hear the follow-up to this than there was between the recording of this and when you're hearing it. And without further delay, please enjoy my conversation with Lloyd Klickstein. [upbeat music] Lloyd, thank you so much for making the trip up to San Francisco today. I know you didn't come here specifically to see me, but I appreciate you carving out a little extra time to meet today.

   2. LKLloyd Klickstein4:33

      I'm happy to be here and looking forward to our talk.

   3. PAPeter Attia4:36

      I hope the view is enticing enough here.

   4. LKLloyd Klickstein4:38

      It's lovely.

   5. PAPeter Attia4:39

      [chuckles] When the weather's nice in San Francisco, there are few things that compare to it. And when it's not, it's like Mark Twain said, right? The worst winter he ever had was a summer in San Francisco or something to that effect.

   6. LKLloyd Klickstein4:49

      [laughs]

   7. PAPeter Attia4:51

      And you're from Boston, so you laugh at that.

   8. LKLloyd Klickstein4:53

      Right now, this is the weather we all wish we had in Boston.

   9. PAPeter Attia4:56

      Yeah. So Tim Wright, one of your colleagues, offered to make this introduction over dinner one night, and there's probably never been in the history of an introduction from the moment the intro was offered until I was sitting down talking to someone on a podcast that was quicker than this one. In other words-

   10. LKLloyd Klickstein5:14

       I'm sorry to hear that, actually.

   11. PAPeter Attia5:16

       Well, it was just meaning I was so excited when we sat there and it was-- So I was with Tim and with D.A. Wallach, who some folks listening will know because I've interviewed D.A. on the podcast as well, and we were having this dinner. And as is always the case when I'm talking with dorky science friends, rapamycin comes up and one thing led to another. And then I'm embarrassed to say this, but the 2014 paper that I talk about constantly, I always refer to as the Manick paper because she's, of course, the first author, but you're sort of the lead author. You're the final author. You're the senior author on that paper. And so I was embarrassed to say this. I didn't even-- When they mentioned your name, I didn't put two and two together. And I didn't know you were at resTORbio at the time either. So anyway, they connected us We communicated over email. The rest is history. We're sitting here today, and I am beyond excited, and then this is a topic that I just know listeners are dying to hear about because it's been over a year since I've had a podcast on this topic. So very early in this podcast, which is about a year and a half ago, we had discussions with David

2. 6:15 – 10:30

   His background and decision to leave academia for translational medicine

   1. PAPeter Attia6:15

      Sabatini and with Matt Kaeberlein, who are both amazing folks and legends in this area as well. So I'm gonna discipline myself for a moment before getting right into the RAPA stuff to give a little bit of background. You've got a pretty interesting background. I want to hear a little bit about it. When did you realize this is what you wanted to do, which was be basically physician scientist and then ultimately now move into industry?

   2. LKLloyd Klickstein6:38

      Well, I guess I can begin by stating that science and medicine is the family business, so it wasn't much of a stretch for me to be here doing what I'm doing now, doing what I've done before on both sides of my family, both sides of my kids' family. All of my kids are scientists, doctors or both.

   3. PAPeter Attia7:01

      So did you do a combined M.D. Ph.D., or did you do them separately?

   4. LKLloyd Klickstein7:04

      Uh, I did the combined one. My wife did them separately, actually, the long and expensive way.

   5. PAPeter Attia7:10

      Yeah, [chuckles] exactly. At least when you do them together, they pay for each other.

   6. LKLloyd Klickstein7:13

      Yeah.

   7. PAPeter Attia7:14

      When did you decide you wanted to focus on immunology, rheumatology? I mean, there, there's no shortage of things one can specialize in.

   8. LKLloyd Klickstein7:20

      One of at least my challenges, and I know the challenge of many physicians and many scientists, is that so many things are interesting. How do you focus? And like many things in life, it was about the people, not the science, that led me into immunology, rheumatology, and, and where I am. When I had left college and wasn't sure where I was gonna go next, I spent a couple of years working in a laboratory at Brigham and Women's Hospital. I had such an incredible time and met such wonderful people that ultimately my decision was to stay there and work with them, learn from them.

   9. PAPeter Attia7:55

      What years were you at the Brigham?

   10. LKLloyd Klickstein7:57

       I worked in a technical capacity from '79 to '81, started medical school in '81 and finished both degrees by 1989, and then stayed there through all of my training and then left in 2006 to join actually Tim Wright's department at Novartis Institutes.

   11. PAPeter Attia8:19

       Hmm. What prompted that decision? And is that a one-way street for most people?

   12. LKLloyd Klickstein8:24

       There are people who go back and forth, but I think we have to be realistic that it's more challenging to go back to academia if you don't have extant grants and external funding. It has to come from somewhere in most places. In terms of what drove the decision, I'm a physician scientist. For me, it's important to do both science and medicine, and it's harder and harder and harder to do that now in an academic environment. At least, I'll get in trouble for saying this, but at least a primitive academic environment like Harvard, where you eat what you kill, and you have to, at the same time, see patients be at the top of not just your game but the world's game in seeing patients and administrative and teaching responsibilities and so forth.

   13. PAPeter Attia9:12

       Well, I mean, let Harvard get upset at you for saying that, but, I mean, there's no denying what you're saying is the case. Every-- I interview so many people who are straddling that, and I'm constantly amazed. In fact, I was interviewing someone recently, a, a very remarkable scientist and academic, and I couldn't believe how much clinical obligation he had and yet how prolific he was. It's sort of amazing to me that some folks can actually straddle that. It's certainly not optimal, I guess, is the point.

   14. LKLloyd Klickstein9:39

       No, and it was much more challenging than I had seen it in the late '70s and early '80s.

   15. PAPeter Attia9:45

       What changed? Is the reduction in grant, the competitiveness of the grant environment or?

   16. LKLloyd Klickstein9:49

       No, it wasn't so much the grant environment. It was more the regulation and the paperwork that was imposed mostly on the clinical side. I need to be fair and say I was both running from something and running to something. As a physician scientist, the goal is to have each of them contribute to the other, and translational medicine, which was a new concept around the turn of the millennium, was growing and was perfect for somebody like me. Novartis Institutes was created by Mark Fishman in the early 2000s as a new concept and a new approach to drug development, thinking about pathway biology,

3. 10:30 – 18:00

   Translational medicine—bridging the gap between basic science and clinical medicine

   1. LKLloyd Klickstein10:30

      and they were building translational medicine departments, and Tim recruited me to lead the musculoskeletal one.

   2. PAPeter Attia10:38

      So maybe explain to folks the difference between basic science, clinical science or clinical research, and translational research, which, as you said, the latter there being a relatively recent phenomenon.

   3. LKLloyd Klickstein10:50

      Mm-hmm. Lots of examples of basic science. One that's pretty exciting and has led to Nobel Prizes is the study of restriction enzymes. Who thought that studying obscure bacteria and how they limit their infection by viruses might have led to the concept of restriction enzymes, which was required for the development of modern molecular biology? Another one of basic science, you've probably talked about CRISPR technology here or-

   4. PAPeter Attia11:22

      We haven't had a dedicated podcast to it, and I'd love to get Jennifer on to do so, but please continue. Yeah, that's a great example.

   5. LKLloyd Klickstein11:29

      I'll give you a one-minute summary. It is another critical element of the bacterial immune system. It's simple, it's elegant, it's powerful, and there were scientists in Europe studying fermentation for yogurt and cheese, and they discovered CRISPR. Jennifer Doudna and colleagues here, MIT and the Broad Institute, and they were studying basic science. They were studying bacterial biology, and it became so exciting when Somebody translated the biochemistry, if you will, in the bacteria to see would it work in humans. Who would've thought that would work? Bacterial chromatin and the DNA is so different, it's super coiled in a bacterial cell, whereas human DNA is organized into chromatin and methylated, but it did.

   6. PAPeter Attia12:27

      So the point here is basic science isn't necessarily in pursuit of anything beyond knowledge, but it doesn't come with the caveat of this needs to have a clinical application with respect to the species of interest.

   7. LKLloyd Klickstein12:43

      Exactly right. Clinical medicine, I think everybody knows. It's getting your flu shot in the fall. It's, uh, being told to diet and exercise and take your antihypertensives if they've been prescribed.

   8. PAPeter Attia12:58

      Right. Does taking this medication lower your risk of a stroke? Does taking this vaccine lower your risk of getting the flu?

   9. LKLloyd Klickstein13:07

      Exactly. And translational medicine-

   10. PAPeter Attia13:10

       There's a big gap between those two, isn't there?

   11. LKLloyd Klickstein13:12

       Yes. And that's what translational medicine does. People had been doing this for a long time, but never in an organized and conceptually holistic way, if I could say that. It's how do you take a basic science observation and make something useful for human health out of it and prove it, which is surprisingly challenging.

   12. PAPeter Attia13:37

       So you're saying that basically up until roughly 20 years ago, this hasn't been particularly well organized, and now pharma companies, among others, are saying, "We'd like to own some of this risk."

   13. LKLloyd Klickstein13:51

       I think everybody has bought into the concept of translational medicine now. Probably all big pharma companies and many small ones do it. Many academic institutions have organizations to do translational medicine. It's in part our responsibility. It's in part a way to do it more efficiently by providing appropriate training and experience to younger scientists. We always have to think back to who's funding our basic science, especially in academia. Ultimately, it's the people.

   14. PAPeter Attia14:23

       Most heavily taxpayer-funded.

   15. LKLloyd Klickstein14:24

       Yes. It's most heavily taxpayer-funded, and the reason they're doing it is to make their lives better or the lives of their family and friends better, and we need to be better at that, and I think this is taking a step in that direction.

   16. PAPeter Attia14:39

       So what was the first translational problem then you began to work on when you joined Novartis in the, what would've been, I guess, the '90s, right?

   17. LKLloyd Klickstein14:46

       It was in the early 2000s. So I joined a musculoskeletal program. Uh, at the time, Novartis was working on, it was a regenerative medicine concept in musculoskeletal biology to increase bone density and increase muscle strength. And so we had to put together some programs that would translate some basic biology observations from human genetics. Remember, translation can go both ways. And in fact, to skip ahead a little bit, we actually did that from that 2014 paper. We took what we learned there and went back into the mouse. And there were a few projects. The one that has been successful is a drug called zoledronic acid to increase bone density.

   18. PAPeter Attia15:33

       And what was the state of assets that you came into? Did Novartis already have a basic program that had shown some new insight with respect to biology that could then be extrapolated into a compound? Did they already have the compound? What was the actual program you were creating?

   19. LKLloyd Klickstein15:53

       At that time, Novartis worked very much like most other pharmaceutical companies did. There was a basic science department led by PhD scientists. There was a clinical development organization led by clinical developers, including MDs. And there was a throw it over the wall mentality. The scientists make something that they like, then they throw it over to the clinical scientists, and they have to figure out what to do with it.

   20. PAPeter Attia16:19

       This is pre-IND?

   21. LKLloyd Klickstein16:20

       Yes.

   22. PAPeter Attia16:21

       Okay. We should explain what an IND is, I suppose.

   23. LKLloyd Klickstein16:23

       Yeah. [laughs]

   24. PAPeter Attia16:24

       Yeah. Do you wanna tell folks what that is?

   25. LKLloyd Klickstein16:25

       Sure. So an IND is, stands for investigational new drug, and this is the application that sponsors make to the FDA to get permission to begin clinical trials. And there are a whole raft of requirements that are necessary in terms of quality, manufacturing, clinical plans, risks and benefits, experiments, and so forth, so that we can make it as safe as possible to test something new in people. But in any event, that's the way Novartis worked is they separated research from clinical development. Other companies did it a little differently. They had the initial testing in healthy volunteers or the initial testing in patients, depending on the risk-benefit argument, as part of the research organization. But in principle, it's the same thing. You had scientists making medicines and then clinicians testing them. The goal of translational medicine is to provide clinical input right at the very beginning of the process, even when you're thinking about what to do. And it really helps to focus the drug development process on the patients and the clinical need right from the beginning so that ultimately the drug that's made is the drug that's needed, not let's make something and figure out what we can do with it. Let's figure out what we need and then make it.

   26. PAPeter Attia17:47

       Is there evidence, by the way, this is a bit of a tangent, but that that transition has rendered pharma more efficient at yielding capital?

   27. LKLloyd Klickstein17:58

       This is studied in an anonymized fashion

4. 18:00 – 21:30

   What prompted Lloyd to focus on mTOR inhibition?

   1. LKLloyd Klickstein18:00

      by an industry organization. It varies by company.

   2. PAPeter Attia18:04

      I see. So let's fast-forward a little bit to the first time you became involved in A molecule that would be involved in a nutrient sensing pathway. What was your foray into that?

   3. LKLloyd Klickstein18:18

      There's a step before that, and that is how did I get from musculoskeletal disease to something new? We have to credit again Mark Fishman, who was the founder of the Novartis Institutes, for this, because he challenged me and a few others to put together an organization within the company and answer the question, what aren't we doing that we should be doing? And then start some projects. And again, it's all about medical need and, of course, scientific tractability. So we started that project. We called it the New Indication Discovery Unit.

   4. PAPeter Attia18:53

      What year is this roughly? Mid-2000s?

   5. LKLloyd Klickstein18:56

      This would have been about 2008 or nine. We basically applied those principles, a real medical need, a problem that's scientifically tractable and that Novartis wasn't working on and ideally that nobody was working on. And we ended up with a few very interesting areas. Joan Manick, who was the first author on that 2014 paper, brought the idea forward. Well, maybe the biology of aging is tractable, but how do we actually make a medicine and develop it?

   6. PAPeter Attia19:30

      Now, was Joan at Novartis at this time?

   7. LKLloyd Klickstein19:32

      Yeah. She joined our group in part to do this. Her real innovation beyond just the idea is that she figured out a way to test a medicine that could alter the biology of aging in humans and find an endpoint that's measurable and modifiable in a reasonable timeframe.

   8. PAPeter Attia19:54

      Which really is the Achilles heel of aging research, which is the ultimate outcome is virtually unmeasurable in the species of interest.

   9. LKLloyd Klickstein20:03

      Yes. So our approach is not necessarily what you might read in the popular press about making medicines for aging. Our approach is to address serious aging-associated diseases, and if we're successful, the side effect will be longevity.

   10. PAPeter Attia20:22

       Yeah. So keep going then. Now Joan floats this idea, which is, here's a really good proxy for aging that can be measured out in a time course that's clinically tractable and also, frankly, amenable to the type of research that we can do in humans. And so what was your aha moment? This is interesting. As in this is interesting to Lloyd.

   11. LKLloyd Klickstein20:47

       I needed, and beyond interesting to Lloyd, we then as a team had to persuade the rest of the organization, "Hey, let's try this idea." And again, we always come back to the medical need, scientific tractability, and in proposing a project, what's the evidence that it's going to be successful? And you know as well as anybody, there's substantial scientific data that mTOR inhibition will extend healthspan in many preclinical species, certainly all the ones that have been tested.

   12. PAPeter Attia21:19

       Now, that was not obvious in 2008. I mean, 2009, people had been speculating, and of course, there was the major publication that came out in 2009.

   13. LKLloyd Klickstein21:29

       I have to

5. 21:30 – 42:15

   Defining mTOR, TORC1, and TORC2, and the consequences of inhibiting them with rapamycin

   1. LKLloyd Klickstein21:30

      correct the timeframe. We started our new indication discovery unit in 2008 or nine. I think Joan started the project in 2010.

   2. PAPeter Attia21:37

      Got it. So you already had a very important study behind you-

   3. LKLloyd Klickstein21:41

      Yes

   4. PAPeter Attia21:41

      ... as a catalyst for that. Let's take a step back now and explain, 'cause it's been a while, and there's gonna be people listening who don't recall all the details of our discussion with David Sabatini and with Matt Kaeberlein. Let's talk about what is mTOR.

   5. LKLloyd Klickstein21:55

      Sure. Well, I can't add anything to David Sabatini about what mTOR is.

   6. PAPeter Attia21:59

      [laughs] Nobody can, but let's assume people have not heard what David has to say.

   7. LKLloyd Klickstein22:04

      Sure. In a nutshell, mTOR is the master integrator of external availability of nutrients and growth factors, and then is the master regulator of the outputs of that integration, deciding whether cells are gonna make proteins, make lipids, make nucleic acids grow, or are we gonna circle the wagons, conserve resources, recycle, and wait during times of little for hopefully future times of plenty. So that's the role of mTOR.

   8. PAPeter Attia22:39

      So it takes a bunch of signals, which are external to the cell, ultimately become internal to the cell because mTOR is in the cell, not out of the cell. It assimilates and integrates across that signal and makes decisions that lead to, as you said, at the risk of oversimplifying, grow or don't grow.

   9. LKLloyd Klickstein22:59

      Yes. I think that's exactly right. The signals it takes are amino acids, glucose, cellular energy, growth factors from other parts of the organism as probably the major ones, and then decides are there sufficient resources that the cell should grow or not.

   10. PAPeter Attia23:18

       And between... Now, this is just a little history lesson for the listeners, sort of between 1991 when Hall first identified what was not called at the time TOR, but what would go on to become TOR in yeast and '94 when Sabatini identifies it in mammals, you basically had some of the, just the heaviest hitters in biology all sort of converging on this idea, which is this is a really ubiquitous thing that has been preserved across about a billion years of evolution with very little change. You don't see that every day in biology. Why is that relevant?

   11. LKLloyd Klickstein23:58

       The simplest argument is that things that have been conserved from single-cell organisms to us are probably important. There's some interesting comparative zoology that's relevant to mTOR here. If you think about where in the cell mTOR lives, it's active on something called a lysosome And that is a structure in the cells that's responsible for breaking down either cellular material or material that's been acquired from outside the cell into its component elements that then could be recycled, like amino acids and sugars and so forth. Very early in development, well, in evolutionary biology, when there were single-celled organisms and then the early multiple cellular organisms, the way that the organism ate was by creating a vacuole from whatever was on the outside and then creating a lysosome.

   12. PAPeter Attia24:57

       So we can sort of picture this endocytotic process is the, the cell membrane or wall, depending on what, if it's eukaryotic or prokaryotic, sort of sucks in a little bit, which creates basically a space, and then the outer parts of that wall reach up, reach around it, and can actually seal, and now you've created like a vacuole that you pull into the cell.

   13. LKLloyd Klickstein25:19

       Yes. And in the early multicellular organisms, there were specialized cells for doing this, and they were called phagocytes for eating cells. Later on, it was learned that phagocytes could also serve an immunologic role. In other words, that they could eat pathogens as well as nutrients. This happened in the late 1800s when higher quality microscopes were available. A Russian scientist named Ilya Metchnikoff did a lot of the pioneering work on this. He was working in Paris, and he described-- He was an embryologist and comparative zoologist, and he described by looking at small animals that were completely transparent, so he could see all the cells inside and what they were doing. He actually imaged them while they were alive, and he could watch them eat, and he could watch them fight bacterial infections. And he was the major champion of something called cellular immunity. At the same time, some German scientists, notably Paul Ehrlich, were working on what we now understand as antibodies. And they said, "No, it's humoral immunity or soluble immunity in your blood." And we had the cellular immunologists in Paris, and we had the humoral immunologists in Germany. Eventually, they figured out they were both right, and they both got the Nobel Prize in 1908. But this is why mTOR is probably on a lysosomal vacuole, because in the context of evolutionary development, it was on these vacuoles that very simplest organisms used to ingest food and nutrients.

   14. PAPeter Attia26:59

       And so you wanna have it close to... Because it's there to sense those things, you wanna have it very close to where they enter the cell.

   15. LKLloyd Klickstein27:07

       Yes, exactly.

   16. PAPeter Attia27:08

       So if we take a given eukaryotic cell today, take one of our cells, how many mTOR complexes would exist in a cell? What order of magnitude?

   17. LKLloyd Klickstein27:18

       I'd turf that question to David Sabatini.

   18. PAPeter Attia27:21

       I don't think I've ever asked David that question.

   19. LKLloyd Klickstein27:23

       I don't know. I would guess it would be on the order of thousands, not millions, not tens.

   20. PAPeter Attia27:31

       So one of the other things that David's done is not just recognizing this in mammals, but also recognizing that mTOR, which again, it's one of those things that's funny when you start to explain it to people because you can't explain what mTOR is without somewhere explaining what rapamycin is given the name. mTOR stands for mechanistic target of rapamycin. But David also played the fundamental role in elucidating that mTOR can be organized in a couple of different ways and sort of two main different ways it can be organized, known as complex one and complex two. Explain a little bit about what those two mean. How do they organize differently? And perhaps more importantly, is there a functional difference between those?

   21. LKLloyd Klickstein28:14

       Sure. So in yeast, there are two separate TOR proteins, one and two. And in, I think all other species, there's just one mTOR protein, and it can be assembled into two different complexes. One of them, or called TORC1, for target of rapamycin complex one, regulates many of the things we've been talking about, so protein synthesis, lipid biosynthesis, protein translation, and so forth. The other complex, TORC2, regulates cytoskeletal, so in other words, the skeleton of the cell's organization and growth decisions. So different.

   22. PAPeter Attia28:57

       Now, this is sort of interesting. So let's talk about rapamycin now. How does rapamycin interact with TOR, its target?

   23. LKLloyd Klickstein29:07

       That's an excellent question because you think about TOR being the target of rapamycin. It's not exactly. The target of rapamycin is an immunophilin called FK binding proteins or FKBP, and there's several of these. There's three different classes of immunophilins. The complex of rapamycin bound to FKBP then binds to the TORC1 complex and inhibits it. And it inhibits it in different ways for different downstream targets. The one that's most commonly measured is something called phospho S6 kinase, which name's not important. It's just this is the protein translation pathway, and it's very efficient at inhibiting that. A little less so for another target called 4E-BP1, and even less so for a target called ULK1, which is involved in activating the cell's recycling machinery called autophagy.

   24. PAPeter Attia30:11

       In other words... Let's go through that again. So rapamycin binds... And how tightly does it bind, by the way?

   25. LKLloyd Klickstein30:18

       Pretty tightly.

   26. PAPeter Attia30:20

       So it binds pretty tightly to this binding protein. This binding protein then moves towards TOR and in the case of... Did we explain raptor and rictor yet? We haven't explained those yet. Do you want to spend maybe just a minute so that they can see the difference between complex one and complex two?

   27. LKLloyd Klickstein30:37

       So mTOR is present in both TORC1 and TORC2 complex, but there are proteins that are unique to each complex.

   28. PAPeter Attia30:46

       So as you were saying, the yeast have two different TOR. Everything else has the same TOR, but it's another binding protein. It's another-

   29. LKLloyd Klickstein30:53

       Yeah

   30. PAPeter Attia30:53

       ... protein bound to it that creates the distinction between complex one and two, correct?
6. 42:15 – 53:00

   Dose-dependent impact of rapamycin on immune function, mTOR inhibition, and toxicity

   1. PAPeter Attia42:15

      targeted by rapamycin.

   2. LKLloyd Klickstein42:18

      It's all about the dose.

   3. PAPeter Attia42:19

      Yeah. So let's talk about those doses. As you alluded to earlier, a transplant patient might be taking five milligrams a day of rapamycin, day in and day out. What types of doses were you seeing that were producing this counterintuitive phenotype?

   4. LKLloyd Klickstein42:39

      Well, if we get back to the mouse paper-

   5. PAPeter Attia42:42

      Yeah, yeah, exactly. Like lower or higher, I guess, is what I'm saying relative to that.

   6. LKLloyd Klickstein42:46

      It's hard to compare, as you have to look at exposures. So the doses on a weight basis or a body surface area-

   7. PAPeter Attia42:53

      They're much higher, typically

   8. LKLloyd Klickstein42:54

      ... were much higher in a rodent experiment, but the exposures can be comparable. They were actually fairly high in his paper. They were at least equal to what we, what we use in transplant. Obviously, we couldn't do that in healthy volunteers, especially healthy elderly volunteers. There was some additional information that gave us some confidence we could use much lower doses than what was used in transplant patients, yielding much lower exposures. And for the listeners, exposures means how much of the drug is actually in your body over time.

   9. PAPeter Attia43:28

      So let's use Cialis as an example of this. I don't know why, but it's just I was talking to a patient about this the other day. Cialis is typically given as either five milligrams or 20 milligrams, and patients typically have a choice if they want to take 20 milligrams, quote-unquote, "on demand." So you're heading into the weekend, you're going away with your wife. It's Friday. You take the 20 milligrams of Cialis, and erectile dysfunction is ameliorated Friday through Sunday. Conversely, another way to take Cialis is to take five milligrams every single day, whether or not you're going to be sexually active or not. But now all of a sudden, any time you want to be sexually active, you're functionally like that person who just took 20. Use the lingo of exposure to explain how those two things are comparable. I don't know why this is somehow [chuckles] the first example that came to my mind, but probably just 'cause it was a discussion I had two days ago.

   10. LKLloyd Klickstein44:29

       It's actually a good example because when you take the medicine doesn't always reflect if the medicine is in your body or not, and medicines that work have to be in your body to work. So the five-milligram dose of Cialis taken once might be in your body for a day. A 20-milligram dose of Cialis taken once is in your body for two to three days. So it's why the higher dose taken once can last over the even long weekend, perhaps, because it's still there. This we call in, in drug development a half-life of the drug. So the half-life of Cialis is long enough that it can do that. Uh, that is not the case for Viagra, for example.

   11. PAPeter Attia45:14

       That's right. Now, there's another interesting thing here, which will also be another-- will have a parallel to the rapamycin story, which is generally patients will tolerate five milligrams daily of Cialis more than 20 milligrams on demand because of the side effects. You have fewer side effects because you don't have the same peak levels. So five milligrams daily will produce a very consistent and narrow gap between peak and trough, which is therapeutic, whereas 20 will overshoot. You'll get a very high peak level, which may increase the side effects, lightheadedness, changes in vision, things like that. And then you have a long enough way down before you hit trough, and it's during that entire window that you have the availability of the effect of the drug.

   12. LKLloyd Klickstein46:03

       Now, that's true for the class of drugs-

   13. PAPeter Attia46:05

       The phosphodiesterase inhibitors, yeah.

   14. LKLloyd Klickstein46:06

       Yeah, PDE5 inhibitors. It's not true for other drugs. Two specific examples are rapamycin, where if you remember when you were treating your transplant patients, you measured trough levels.

   15. PAPeter Attia46:19

       We measured, yeah, daily. I mean, we were constantly doing this.

   16. LKLloyd Klickstein46:22

       But you measured the trough levels, not the peak levels.

   17. PAPeter Attia46:24

       Not the peak. That's right.

   18. LKLloyd Klickstein46:25

       Because the side effects are driven by the trough levels as well as the efficacy.

   19. PAPeter Attia46:28

       And I think that's also true with gentamicin-

   20. LKLloyd Klickstein46:31

       Exactly

   21. PAPeter Attia46:31

       ... and a lot of the negative-- the antibiotics that have the same toxicities on the trough, right?

   22. LKLloyd Klickstein46:36

       Yes. So gentamicin, years ago, we used to dose three times a day. In modern times, we dose it once a day, and we get better efficacy and far fewer, uh, side effects.

   23. PAPeter Attia46:48

       So why is that the case, that a drug like gentamicin or rapamycin is producing toxicity by its nadir, not its peak?

   24. LKLloyd Klickstein46:57

       Every drug is different, and it depends on the specific mechanism. For gentamicin and aminoglycosides in general, remember, these work on the bacterial ribosome, and there's some congruency between mitochondrial ribosomes and bacterial ribosomes, and with sustained inhibition, that can cause toxicity, particularly in the kidney, in the tubular epithelial cells, also in inner ear hair cells and some other places. So having some drug-free time seems to allow the organelles to recover. At least that's the hypothesis I heard in medical school. We all know that half of what we learned in medical school is wrong, and they just weren't sure which half.

   25. PAPeter Attia47:40

       You had a better medical school than me. I think 90% of what I learned in medical school is wrong. But you went to Harvard. I only went to Stanford, so I think that's the West Coast/East Coast difference. No, I think that's-- I mean, to me, that is the most logical argument, which is drugs that have trough toxicity are drugs where you must have a break from the drug.

   26. LKLloyd Klickstein48:00

       Mm-hmm.

   27. PAPeter Attia48:00

       And the higher the trough, the lower the probability of a break. Peak drugs aren't about time away. It's literally too much of this thing eventually hits a trigger. That's probably an oversimplification, but-

   28. LKLloyd Klickstein48:13

       It's a useful conceptual framework.

   29. PAPeter Attia48:15

       Yeah. So let's-- Now, taking that model back, the first glimmer of hope that this drug had wasn't uniformly immune-suppressing was, "Well, what if we dose this lower?" basically. And not from the standpoint of side effects, 'cause that's a common reason you'd go lower, but actually change The profile of inhibition, was it known at the time that that's what they were trying to do? Like, did they have enough insight into how rapamycin bound to the two different complexes to test this hypothesis proactively, or was this more empirical, an observation that after the fact the mechanism became elucidated?

   30. LKLloyd Klickstein48:57

       We had some information up front. One bit of information that the mechanism could be favorable for immune function, not solely immunosuppressive, was looking again in your transplant patients at those who were on a calcineurin inhibitor versus those who were on a rapalog, and there was a significant trend that those on rapalogs had fewer cytomegalovirus infections than those on calcineurin inhibitors, all other things being equal. An observational study not as well controlled as ideally we would like, but it was intriguing.
7. 53:00 – 1:13:00

   Lloyd’s 2014 experiment—mTOR inhibition improves immune function in the elderly

   1. PAPeter Attia53:00

      seen, actually. So let's now talk about this experiment. I'll tell you from my vantage point the day I'll never forget, which is I remember getting an embargoed copy on the day before Christmas, so it's Wednesday, December twenty-fourth. It's probably noon. It's funny, I was in my office, which is dumb. Why was I in my office at noon on Wednesday, the day before Christmas? I certainly shouldn't have been, but I remember being in my office, and I remember how sunny it was. I remember what a beautiful day it was, and I remember someone from The New York Times emailing me the embargoed copy, and it's embargoed... Yeah, it was embargoed for another couple of hours. The person at The Times who sent it to me knew how interested I was in the subject matter, and I'm reading this thing and I'm like, "This is unbelievable." I just couldn't believe what I was reading. And I have a background in immunology, so of course, I can understand what these figures are showing. Give people a sense of how long it takes to get there. So if the public is first seeing this in December of 2014, when did the experiment start? And I didn't mean that conceptually. Like, I don't just mean you're enrolling patients. Like, this is a, about a four or five-year journey, right?

   2. LKLloyd Klickstein54:10

      That's right. About 2010 we started.

   3. PAPeter Attia54:12

      So what was the hypothesis that you wanted to test and that you, Joan, and the team wanted to test?

   4. LKLloyd Klickstein54:18

      There was some pre-work before we could ask the question. The pre-work was, one, we reviewed the existing literature. We, especially that paper from Chen. And we then looked at some other work that had looked at drug levels in cellular systems necessary to partially or fully inhibit the target. And we had to look at a lot of different cells because TORC1's biology While in the big picture is the same in different cells, the sensitivity of the complex to the drug is different in different cells, and we have some hypotheses now for why that is. And we then did some modeling to understand whether the low doses, and we looked at internal data that the company had to see could we come up with a low dose and a schedule that would yield exposures in people that would partially or fully inhibit TORC1, yet give less than assay trough levels to help ensure safety in the healthy volunteers.

   5. PAPeter Attia55:23

      Now, Lloyd, was this mostly because at the time you wanted to see if it even made sense to pursue a new molecule entirely that would inhibit complex one or so-called selective inhibition, but the idea is why go down that path of doing that without a proof of concept that says it works? Or did you think at that point in time, if we can get this to work, you would never need a selective mTORC1 inhibitor?

   6. LKLloyd Klickstein55:50

      You're asking really for Novartis thinking that's probably still confidential.

   7. PAPeter Attia55:55

      Okay.

   8. LKLloyd Klickstein55:55

      But the big picture is we want to know if something works. We want to figure out if we can make it better. Again, ultimately, Novartis, we at resTORbio, and hopefully everybody at a pharmaceutical company is thinking about how can we make patients' lives better, and then everything else is important, but secondary to that. And then what do we measure? What dose do we use? How frequently do we give it? How long do we treat people? How do we answer the question clearly? What do we measure? All of those questions had to be answered, and they had to be answered before Joan brought the program to the decision board of the company to say, "Give us a lot of money to do this experiment." Each of these clinical experiments cost millions of dollars.

   9. PAPeter Attia56:40

      And at the time, RAD001 was FDA approved for another indication or no?

   10. LKLloyd Klickstein56:45

       Yes.

   11. PAPeter Attia56:46

       It was already approved in cancer or in...

   12. LKLloyd Klickstein56:49

       I think it was in renal cell.

   13. PAPeter Attia56:52

       RCC?

   14. LKLloyd Klickstein56:52

       Yeah.

   15. PAPeter Attia56:53

       Yeah. Okay. So that only raises the stakes of what you're asking because you're taking a drug that's already gone through phase three, and you're going to spend a lot of money on it that you technically don't need to spend. Is that a common thing to do inside of a company as large as Novartis, to take a drug that basically you're trying to make the case for a totally different use?

   16. LKLloyd Klickstein57:16

       Yes. I suspect most companies do things like this, where when a drug is registered in one indication, if you can find others, it's a good thing.

   17. PAPeter Attia57:26

       So, I mean, for the sake of time, I will just, I mean, basically say that you guys did something kind of amazing, which is with so little human data, you did a great job of identifying the right patient population, identifying the right primary outcome, identifying a correct power analysis so you wouldn't miss the signal. So in other words, you didn't know how to power the study, which means you had to have a sense of how much the benefit was going to be, knowing how long to pulse, how to dose. I mean, this could have gone sideways six other ways.

   18. LKLloyd Klickstein58:04

       It could have. We had some additional help too. At the time, Novartis had a vaccines group, and they had commercialized a flu vaccine, so we knew a lot about flu vaccination and responses required for making a clinical difference and so forth.

   19. PAPeter Attia58:24

       So let's walk people through the study design. You've got what, about 300 people aged 60 plus, more or less?

   20. LKLloyd Klickstein58:30

       I think it was 218 in that 2014 paper. Everybody was over 65, no unstable medical conditions. And-

   21. PAPeter Attia58:39

       Were these subjects all in Australia? Was there something about this that was Australian?

   22. LKLloyd Klickstein58:43

       Well, because this was a flu vaccination, so let's just skip ahead. The endpoint of the study, the primary endpoint by which we were going to decide did the study work or not work, was the response to a flu vaccination, the seasonal flu. Now, because it's a seasonal vaccine, we had to do the study when we were ready, wherever in the world people were about to get their flu vaccines. In that paper, we were ready for the Southern Hemisphere because our summer is their winter.

   23. PAPeter Attia59:10

       Right. And since the CVS in the Antarctica ran out of vaccine that year, Australia made the most sense.

   24. LKLloyd Klickstein59:15

       [chuckles] Australia and New Zealand.

   25. PAPeter Attia59:17

       Yeah. So there are four arms in this study. There's a placebo arm that gets just, obviously, a placebo. There's three treatment arms, one that gets 0.5 milligrams of RAD001 daily, so everolimus. There's a group that's getting five milligrams once a week, and there's a group that's getting 20 milligrams once a week. So it's a clever design because the five and the 20 that are both getting it once a week gives you a great-- You get to answer both efficacy and toxicity questions as they pertain to that dose. The 0.5 daily versus the five weekly is your closest aggregate dose where you get to see is there a difference in trough. So overall, a lot of interesting stuff. What was your personal null hypothesis? Not necessarily the same, but do you recall what your null hypothesis was going into that experiment?

   26. LKLloyd Klickstein1:00:16

       I mean, obviously, the null hypothesis is that there's no drug effect.

   27. PAPeter Attia1:00:20

       Yeah, sorry. What was your first alternative hypothesis, I guess, is a better way to say it.

   28. LKLloyd Klickstein1:00:25

       This was a l- little bit less hypothesis testing the way that academic investigators work than it was asking questions. And the question was, and there were several, but at a high level, it's can we see an improved vaccine response at an acceptable level of toxicity that would have this drug make sense? And that's the high level question. And you went through the doses and schedules we used, and we tested three different ones because each of those doses did a different thing to TORC1 inhibition. The .5 milligram dose partially inhibited in a sustained fashion. The 5 milligram once a week fully inhibited TORC1 for a couple days out of the week. And the 20 milligrams we modeled would fully inhibit TORC1 over the dosing interval.

   29. PAPeter Attia1:01:20

       I didn't realize that, actually. 20 is so high that it gave you functionally nonstop inhibition of mTORC1 until your next dose.

   30. LKLloyd Klickstein1:01:29

       Yeah.
8. 1:13:00 – 1:18:45

   Insights into autophagy, antigen presentation, and the pleiotropic benefits of a rapalog, and how it compares to fasting

   1. PAPeter Attia1:13:00

      specific

   2. LKLloyd Klickstein1:13:00

      Yes. Yeah. There's a small literature on that.

   3. PAPeter Attia1:13:03

      What else did you see in this paper? I mean, I think we've touched on the high points.

   4. LKLloyd Klickstein1:13:06

      Yeah. The other experiment we did, which I think we mentioned in the text but didn't go into great details, is the flu vaccine is a T-dependent antibody response. We also vaccinated patients with a 23-valent pneumococcal vaccine, which is-

   5. PAPeter Attia1:13:24

      Which is B cell

   6. LKLloyd Klickstein1:13:25

      ... which is a pure polysaccharide vaccine, so it's a T independent response. We were thinking, could we improve antigen presentation perhaps if the dose of the rapalog we used augmented autophagy, and could that contribute to antigen presentation? We saw and we measured seven of the 23 antigens.

   7. PAPeter Attia1:13:49

      Wait, tell me why that would be-- That's not an obvious purview into autophagy to me. So let's back that up a little bit. So you're giving them a pneumococcal vaccine, which is what type of vaccine? That's a-

   8. LKLloyd Klickstein1:14:03

      Polysaccharide antigen

   9. PAPeter Attia1:14:04

      Polysaccharide antigen. You're not giving back the whole bacteria. And how does it get presented to the immune system?

   10. LKLloyd Klickstein1:14:11

       There are specific elements of innate immunity that recognize bacterial polysaccharide antigens, and that brings it to professional antigen presenting cells, likely dendritic cells.

   11. PAPeter Attia1:14:23

       Mm-hmm.

   12. LKLloyd Klickstein1:14:23

       Then it has to be internalized and then presented.

   13. PAPeter Attia1:14:26

       So that's MHC class one?

   14. LKLloyd Klickstein1:14:29

       This isn't a peptide presentation. This is presented in the context of an innate element that recognizes polysaccharide antigens.

   15. PAPeter Attia1:14:36

       Okay. All right. So we're outside of class one, class two.

   16. LKLloyd Klickstein1:14:40

       Yes. Yes.

   17. PAPeter Attia1:14:41

       And you're saying the ability to internalize, or basically the ability to phagocytose that lipopolysaccharide and then-

   18. LKLloyd Klickstein1:14:50

       And directly stimulate B cells.

   19. PAPeter Attia1:14:52

       Yeah.

   20. LKLloyd Klickstein1:14:53

       It was an exploratory element of the study. We saw in the seven specific antigen responses we measured, if I recall, six of them increased, but by a small amount. It was a encouraging trend, but we didn't further follow it up.

   21. PAPeter Attia1:15:09

       Okay. Any other markers you could have f- here for autophagy? I mean, did you look at light chain transition or anything like that?

   22. LKLloyd Klickstein1:15:17

       No. Autophagy is a really difficult clinical investigation paradigm. And I know you recently saw Mitch Weiss's paper on unpaired hemoglobins in thalassemia patients. I was super excited when I read that paper because here is now a clinical paradigm where we can test drugs that augment autophagy and see something easily measurable in a not that rare patient population.

   23. PAPeter Attia1:15:45

       Yeah. Let me think. In those patients, did you collect serum that allow you to look at amino acid levels in the plasma or anything else?

   24. LKLloyd Klickstein1:15:54

       No, we didn't do any of that.

   25. PAPeter Attia1:15:55

       Do you still have any of that banked serum?

   26. LKLloyd Klickstein1:15:57

       [laughs] I don't think so.

   27. PAPeter Attia1:16:00

       Easy enough experiment to repeat. But, but of course, the other thing I'm curious about is, is there anything about RAD001 administration that mimics fasting, for example? I mean, how much of the benefit here is through direct inhibition of mTOR? And are there any pleiotropic benefits that aren't quantified through this? Obviously, some of them-- I mean, the fact that you waited until the drug was out of the system to check the immune response is actually a great insight, 'cause obviously you eliminate some of those things. But in the way that many people have argued statins have a direct effect, they inhibit cholesterol synthesis, an indirect effect, the liver upregulates LDLR, a really indirect effect, which is immune suppression or other sort of benefits around endothelial health and things like that. Do you think there's a possible third leg to this stool that we haven't thought about?

   28. LKLloyd Klickstein1:16:54

       The fasting story's kind of complex. So do I think there's some other persistent benefit of, of a rapalog? I think the mouse experiments tells us there is, and it's because relatively short course of a rapalog is nonetheless sufficient to extend a mouse's lifespan. And we do not understand that.

   29. PAPeter Attia1:17:18

       Although it's so hard to extrapolate what short versus long means in a mouse, isn't it?

   30. LKLloyd Klickstein1:17:23

       Yes.
9. 1:18:45 – 1:29:00

   Lloyd’s 2018 experiment—TORC1 inhibition enhances immune function and reduces infections in the elderly

   1. PAPeter Attia1:18:45

      the way.

   2. LKLloyd Klickstein1:18:45

      Yeah.

   3. PAPeter Attia1:18:45

      Negative studies not getting published.

   4. LKLloyd Klickstein1:18:47

      And I think it's a pet peeve of a lot of people. It's hard enough to publish positive studies, and I'm sympathetic and agree.

   5. PAPeter Attia1:18:55

      Yeah. So we're high-fiving on New Year's Eve 2014. How do you go from what does Novartis d-- and again, if this is confidential, by all means, just gloss, you know, we'll skip it. But what do the brass at Novartis think of the results of this experiment, which is effectively taking a drug that we already have on the market for a very clear indication and now potentially expanding an indication? Can the FDA take a study... This is a very well-done study here. This is double-blinded, this is placebo-controlled, and this found a significant outcome. Is that enough to change the indication for a medication like this?

   6. LKLloyd Klickstein1:19:34

      I can speak in general in that for an indication that could be relevant to many, many people, you need a corresponding, um, a lot of safety data. This study was way too small for studies that would be required for marketing authorization.

   7. PAPeter Attia1:19:53

      I got it. So because something like renal cell carcinoma is relatively infrequent relative to influenza vaccination, you had enough safety data to justify treating people with RCC. This would not constitute sufficient safety data to basically give every person over the age of sixty-five who's getting vaccinated this type of a medication.

   8. LKLloyd Klickstein1:20:14

      That's exactly right. If we fast-forward a little bit in the conversation, we've advanced this program in resTORbio, Novartis licensed it to resTORbio, and our phase III program is two very similarly designed clinical studies. One has a thousand patients, the other one will have about sixteen hundred patients.

   9. PAPeter Attia1:20:35

      You able to speak about how the decision was made for resTORbio to basically acquire a piece of an asset from Novartis and, and what else was brought in to create that company, and how did you, Joan, and I assume many others decide to leave? I mean, that's obviously a loss to Novartis, presumably, which implies that they probably still have a vested interest in the success of resTORbio.

   10. LKLloyd Klickstein1:20:58

       Yeah, let's take one step backwards and answer an earlier question you asked, which is, what did Novartis think when we got these results?

   11. PAPeter Attia1:21:05

       Oh, yes, yes. Thank you. Yeah.

   12. LKLloyd Klickstein1:21:06

       And I think everybody was very excited for reasons that you're excited.

   13. PAPeter Attia1:21:11

       That was my Christmas present of the year.

   14. LKLloyd Klickstein1:21:12

       Yeah. [chuckles] And, and the guidance was, "This is so important, let's go back and do it again. Try to do it in a more TORC1 selective way."

   15. PAPeter Attia1:21:24

       Are you able to say how much that study cost, just to give a sense of-

   16. LKLloyd Klickstein1:21:27

       I don't think we talk externally, but any clinical study like this, a phase II study with two to three hundred patients costs millions. And a lot of the cost is driven by often exploratory assessments you do in the context of the study beyond the per patient cost and investigator cost. But millions. I mean, it's a lot of money for anybody, and it's done with a lot of deliberation and thought. So the guidance was to go back and do it again, make sure it's real, come up with a way to be more TORC1 selective.

   17. PAPeter Attia1:22:02

       But using the same vehicle, which means b- putting a finer point on the dosing, not necessarily... I mean, you're still not at the point where people are saying, "We need to make a new molecule to replicate this"?

   18. LKLloyd Klickstein1:22:14

       Well, we had one.

   19. PAPeter Attia1:22:16

       Oh.

   20. LKLloyd Klickstein1:22:17

       The research team at Novartis had come up with a very cool finding that a combination of an allosteric and catalytic TORC inhibitor could be more TORC1 selective and more potent. There was actually synergy, and this is published by Beat Neefeler and Lone Murphy. They showed synergy of, so a rapalog-

   21. PAPeter Attia1:22:42

       Can you explain to folks what the difference is between allosteric versus catalytic inhibition?

   22. LKLloyd Klickstein1:22:46

       Sure. So catalytic inhibition means an inhibitor that's binding at the catalytic site of TORC1 and blocking phosphorylation of targets. An allosteric inhibitor is a fancy way of saying an inhibitor that binds someplace else on the molecule and nonetheless inhibits it. Rapamycin complex-

   23. PAPeter Attia1:23:08

       I always think of allosteric as sort of shape blocking.

   24. LKLloyd Klickstein1:23:11

       Could be.

   25. PAPeter Attia1:23:12

       Yeah.

   26. LKLloyd Klickstein1:23:12

       Let's say shape blocking. So in this case, the allosteric inhibitor is the combination of FKBP-twelve plus rapamycin binding to TORC1. So the combination of those two synergistically inhibits TORC1, and it's a little more TORC1 selective.

   27. PAPeter Attia1:23:30

       Everolimus does the same thing. It also binds to FKBP.

   28. LKLloyd Klickstein1:23:35

       Yes, it binds to FKBPs also. Maybe later on we can get to that Laming paper, which is-

   29. PAPeter Attia1:23:41

       Which sh-- yeah, I'd love to get to that paper.

   30. LKLloyd Klickstein1:23:42

       Yeah.
10. 1:29:00 – 1:40:00

    Creation of resTORbio, subsequent studies, and takeaways about dosing, TORC2 inhibition, and tissue selectivity

    1. LKLloyd Klickstein1:29:00

       patients.

    2. PAPeter Attia1:29:01

       Was this the one published two years ago?

    3. LKLloyd Klickstein1:29:03

       Yes, 2018.

    4. PAPeter Attia1:29:04

       Oh, yeah, yeah, yeah, a year ago. Okay. So let's now talk about the creation of resTORbio.

    5. LKLloyd Klickstein1:29:10

       Mm-hmm. So essentially, the story is that we did the second study for prevention of respiratory tract infections and enhancing immune function with mTOR inhibition. Worked again. Everybody's excited. And Novartis, as in most big companies, big pharma companies, the research teams produce more than global development can handle, and it's done deliberately. It gives early in drug development, you never know exactly what's going to work best. You want to create enough opportunities so something will be exciting. And the program transitioned to global development, and they had a lot of exciting things to do, and this fell below the funding line. It reflects, in part, the excellent productivity of Novartis research. It reflects, in part, the great opportunities the global development has. Of course, as the champions of the program, we were kind of disappointed. But Novartis felt, and again, I'm speaking for myself now, I'm not a Novartis spokesperson, but Novartis felt this drug looks like it could work, and it could help people. We have to find a way to make it available to people if it could work. So other pharma companies do this, too. The decision was to out-license it. And Joan is the sort of originator of the idea and the biggest champion, wanted to go outside of Novartis and start a company. I introduced her to an absolutely awesome CEO I know who was ready for his next role, and they raised money, and they created resTORbio.

    6. PAPeter Attia1:30:50

       And that was a pretty quick path to going public. resTORbio went public late in '18, didn't they?

    7. LKLloyd Klickstein1:30:55

       It reflected, in part, the need for funds to run a phase III program.

    8. PAPeter Attia1:31:00

       Yeah. What did resTORbio raise in the IPO?

    9. LKLloyd Klickstein1:31:03

       Uh, you're asking me a hard question. I was at Novartis But probably around 90 million, I think.

    10. PAPeter Attia1:31:09

        Wow. Yeah. So yeah, as you said, that's-- you're basically going right to phase three at this point because... So you licensed one or two molecules from Novartis?

    11. LKLloyd Klickstein1:31:18

        resTORbio licensed BEZ235, which is now named RTB101, and they then did a phase 2B study. These two studies we had done were phase 2A, if you will.

    12. PAPeter Attia1:31:31

        Phase 2A, yeah.

    13. LKLloyd Klickstein1:31:31

        Right. So in the first study published in 2014 that we've been discussing, respiratory tract infections and infections in general were observed to be decreased in the drug-treated group compared to the placebo by reviewing the adverse event listings. This was not something we had considered a priori, but we recognized decreased infections could be a consequence of improved immune function, which is why we looked in the first place in the listings. And then in the second study, where we explored a catalytic inhibitor, which is now RTB101, RAD001, as well as the combination, we promoted respiratory tract infections and infections in general to a secondary endpoint, and we specifically included collecting those data both by patient reporting as well as investigator querying the patients at home regularly. And again, we saw decreased respiratory tract infections. The best drug was BEZ235, which we now call RTB101 in terms of decreasing respiratory tract infections. The combination also worked. Interestingly, the combination, as well as RAD001, improved the flu vaccine response, but the BEZ235 or RTB101 did not.

    14. PAPeter Attia1:32:58

        Remind me, it's catalytically inhibiting, so it's binding directly to TOR?

    15. LKLloyd Klickstein1:33:05

        Yes.

    16. PAPeter Attia1:33:06

        And is it binding equally to TOR when bound to raptor, meaning complex one, as it is binding to TOR bound to rictor, known as complex two?

    17. LKLloyd Klickstein1:33:18

        So the way this is usually done is in a cellular assay context, so we don't look specifically for the binding, but we look for inhibition of phosphorylation of sites.

    18. PAPeter Attia1:33:30

        Of serine six, or which one?

    19. LKLloyd Klickstein1:33:32

        S6 kinase for TORC1 and phospho-Akt there. And we look specifically at the phosphorylation site that TORC2 does, not the one that any other enzyme does. So we're able to see that a catalytic inhibitor at high concentrations will inhibit both. RTB101 has some preference for TORC1, and it's a little different depending upon which cell you look in.

    20. PAPeter Attia1:34:00

        I wanted to come back to that because, and I got to remember to where we are in this story, because I don't want to lose this thread. So maybe we can agree to just park this again, but I definitely don't want to leave the discussion of tissue selectivity. We've focused so much on C1, C2 selectivity, but we haven't talked about muscle versus liver versus adipose tissue, for example, which you could argue you might want very different behaviors there. In terms of drug design, drug pharmacokinetics, is it easier to target tissues or is it easier to target enzymes, proteins, et cetera, when designing a drug or waving magic wands?

    21. LKLloyd Klickstein1:34:44

        It, no magic wands involved. It's far easier to design a drug to hit a target. To hit the target in a particular tissue is harder, but doable. Sometimes you can do it in a deliberate designed fashion. For example, making a prodrug that's cleaved to an active form only by an enzyme present in your desired tissue. You also have to be mindful that within every tissue there are multiple cell types, and you want the drug in the cell type that will make the difference. And again, all of this is possible, and it's just how much time and effort are you going to put into it.

    22. PAPeter Attia1:35:21

        So when you go back to even the first experiment in 2014 and all of the animal data that came from it, did you have a sense of where this was acting tissue-wise? Did you feel like you were acting on bone marrow? Did you feel like you were possibly acting in the thymus? Did you feel like you were acting in s-some other cell line that directly or indirectly was playing a role? I mean, or did you have a sense that you were seeing this everywhere, but it didn't seem to matter except in the bone marrow?

    23. LKLloyd Klickstein1:35:52

        We thought it would be bone marrow and perhaps secondary lymphoid tissue, uh, which are lymph nodes or glands, but we didn't explore it exactly. In general, small molecules that aren't specifically tissue targeted will often go to many tissues. We knew from toxicology studies with the compound that it distributed to our target tissues. We felt we had enough information to move ahead.

    24. PAPeter Attia1:36:18

        Yeah. So when RTB101 was basically the basis upon which resTORbio was formed, correct?

    25. LKLloyd Klickstein1:36:26

        That's right.

    26. PAPeter Attia1:36:27

        Now, I was very confused during your roadshow, which was about a year ago, maybe more than a year ago. It might've been early 2018. I've sort of lost track. You were at Novartis at the time, so it wasn't really your roadshow at the time. But I naively, I guess, thought that RTB101 was actually RAD001, the everolimus, combined with a PI3K inhibitor. So that's actually what I thought was happening, and I remember even having discussions with other people, looking at the data and saying, "Is this what this company is?" So I assumed that this company out-licensed everolimus combined with a PI3K inhibitor. So how were we confused by that?

    27. LKLloyd Klickstein1:37:07

        When resTORbio was formed, it licensed RTB101 from Novartis for all uses. And there was also a limited license to use RAD001 only in combination with RTB101 for our indication. Now, the Phase 2b study that resTORbio ran showed that the most effective drug or drug combination for preventing respiratory tract infections was just RTB101 alone at ten milligrams. And remember, the previous study that Novartis had run had shown that although the combination was best at augmenting a vaccine response, it was just RTB101 alone, which at the time was called BEZ235, was the best at preventing respiratory tract infections. We believe this is because the mechanism by which it prevents respiratory tract infections is upregulation of an interferon-stimulated antiviral gene response. Interferon, remember, is a substance in the blood that upregulates many different proteins, most of which are involved in preventing viral infections. And you need protein synthesis to make all of these proteins. And I worry that if we inhibit mTOR for a long time, we can upregulate the genes, but they won't be expressed adequately. And there are some literature data that you need mTOR in order to express the proteins induced by interferon.

    28. PAPeter Attia1:38:50

        So these experiments taken together suggest to you that, I guess it just reinforces this idea of intermittent dosing, not just intermittent within the week, which I think was clearly established by the Phase 2a study, but even applying a secondary cycle over the course of a year, for example. I mean, you know that doing a six plus two once a year is probably not adequate, so there's some frequency upon which you want to meta cycle that. But the reason you don't just want to go all the time taking it, presumably, is you might actually start to impair protein synthesis that's necessary to, for lack of a better word, basically empower your new superpowers of immunity through enhanced protein synthesis.

    29. LKLloyd Klickstein1:39:36

        Yes. Protein synthesis, there's several different kinds of protein synthesis, and some are more or less sensitive to inhibition by rapalog. Mitch Weiss's very recent paper, one of the interesting things I found in it was that there wasn't much of an inhibition of hemoglobin synthesis, despite the fact that they were using

11. 1:40:00 – 1:47:00

    Comparing the longevity effect of rapamycin, fasting, and caloric restriction

    1. LKLloyd Klickstein1:40:00

       fairly high exposures of a rapalog. So I think there are some proteins that are sensitive to translational inhibition by rapalogs and perhaps some that are less sensitive.

    2. PAPeter Attia1:40:10

       Before we go down this path of getting a little bit more into RTB101, I want to take a step back here and say, do you think that all of the benefits that we saw in the ITPs across all these other species, if you think of the benefits that Matt Kaeberlein is seeing in dogs, if you think of sort of the global excitement that exists around rapamycin and rapalogs, how much of it do you think is mediated through what you guys are testing, which is you're clearly enhancing immunity in a positive way, which could have at least two very distinct benefits. One is the reduction of infection. The other could be, frankly, reduction of cancer through increased surveillance. They're very similar. Viruses and cancer obviously behave or susceptible to the similar branch of the immune system. Do you think there are other things that we haven't talked about yet, such as increased autophagy, targeting of and/or destruction and/or de-silencing of senescent cells, reduction of inflammation, enhanced mitophagy? What other mechanisms do you think could be involved here, and what evidence exists to support or refute that?

    3. LKLloyd Klickstein1:41:18

       Well, I think we know from academic experiments that every single one of those mechanisms can extend healthspan in preclinical models. We do not know in people, and I think similarly, to follow up our earlier discussion about what tissues you have to inhibit mTOR in in order to get a clinical benefit, we don't really know the answer to that either. It's been studied in some of the preclinical models. I can recall an experiment in the Drosophila fat body where inhibition of mTOR right there was sufficient to extend a fly lifespan. There's still a lot we need to learn.

    4. PAPeter Attia1:41:56

       What does your intuition tell you? How much of an overlap or parallel do you see between the benefits of fasting and caloric restriction and the benefits of rapamycin globally?

    5. LKLloyd Klickstein1:42:06

       Yeah. So one of the interesting things that we did and was done previously in a Nature publication, I think the author was Sengupta, was looking at the consequences of fasting on mTOR activity. In young people, as you would expect, fasting leads to suppression of mTOR activity, activation of the cellular recycling machinery, autophagy, suppression of protein synthesis and DNA and lipid synthesis and so forth. Basically preparing for lean times. In old mice, that's impaired. We've only done the liver tests in mice. So we back translated this experiment and gave... Actually, I think it was rats. It was old rats, doses of mTOR inhibition that corresponded to the doses we were using in people that were well tolerated, and then we looked at their ability to suppress mTOR. So in the old rats, even with fasting, their mTOR was still active in the liver. In a young rat, it's suppressed.

    6. PAPeter Attia1:43:16

       So the young versus old had the same degree of inhibition to the same dose of rapamycin?

    7. LKLloyd Klickstein1:43:21

       Well, you couldn't test in the young rats because their mTOR was already low.

    8. PAPeter Attia1:43:26

       Oh, but if you did it outside of the fast, I mean.

    9. LKLloyd Klickstein1:43:29

       Well, certainly the exposures were the same. There was no age-dependent difference in exposure of the liver or the blood.

    10. PAPeter Attia1:43:37

        That's interesting. Does that suggest that the older animal lost the ability to respond to the environmental reduction in nutrient?

    11. LKLloyd Klickstein1:43:46

        Exactly. Exactly.

    12. PAPeter Attia1:43:49

        Hmm. That's upsetting. Although it does explain a very interesting finding, which is everything comes back to the 2009 paper. What really was interesting scientifically was that those mice were 600 days old. Those were mice that if you fasted them, wouldn't have lived longer. They'd already passed that stage where caloric restriction would extend their life, and yet their lives were extended 15% and 25% by rapamycin. That was a big freaking deal.

    13. LKLloyd Klickstein1:44:22

        Yeah. We published our experiments in that 2008 paper. It was, it was sort of an interesting back translation experiment where we treated the old rats based on what we knew about the old people. And of course, we could do in rats what we can't do in people, is take their livers out and study their mTOR inhibition. But we weren't the first ones to do that. There was a very good Nature paper that showed the same thing.

    14. PAPeter Attia1:44:44

        Do you think this applies to humans? I mean, do you think that intermittent periods of caloric restriction are not beneficial to people in their 60s or 70s, which would be the equivalent of those, quote-unquote, "old rats"?

    15. LKLloyd Klickstein1:44:56

        The only thing that our group has been able to try is we looked at whether we could detect mTOR activity as assessed by things like phospho S6 kinase in the peripheral blood leukocytes of old people, and we couldn't detect activity. We can't answer the question. I think we would need liver samples under fasting conditions.

    16. PAPeter Attia1:45:15

        I mean-

    17. LKLloyd Klickstein1:45:15

        Are you volunteering?

    18. PAPeter Attia1:45:17

        Yeah, I'm absolutely volunteering. No, I tell you, there's a lot of things I subject myself to. I'm never excited about the liver biopsy. I just [laughs] -- I think that's the problem of doing a residency in general surgery, is you've had one too many calls down to the interventional radiology suite with the patient that you have the recency bias of you only remember all the cases of liver biopsies gone bad. The-- All those hepatologists that have never had an issue, you don't hear about those cases, but you hear about every one that-

    19. LKLloyd Klickstein1:45:43

        Yeah. There's sort of a referral bias. You never see the thousand that go well.

    20. PAPeter Attia1:45:47

        Yeah.

    21. LKLloyd Klickstein1:45:47

        You only see the one that didn't.

    22. PAPeter Attia1:45:49

        Yeah. I don't know. I think at some point I'll probably have to sign up for a liver biopsy. I think there's a lot going on there. There's so many questions I have about the liver.

    23. LKLloyd Klickstein1:45:56

        [laughs]

    24. PAPeter Attia1:45:57

        Especially my own.

    25. LKLloyd Klickstein1:45:58

        No liver biopsies. You can get samples other ways, at least for this reason. But it is an interesting open question, and yet another one of these things we don't know is, is mTOR suppressed in elderly people with fasting and in which tissues?

    26. PAPeter Attia1:46:14

        And by the way, do we know if autophagy is impaired in older folks with fasting? Because autophagy and mTOR inhibition are not synonymous.

    27. LKLloyd Klickstein1:46:26

        That's right.

    28. PAPeter Attia1:46:26

        They overlap, but they're not synonymous.

    29. LKLloyd Klickstein1:46:28

        Yeah. Well, there's a lot of biology there, and you-- it's not only mTOR that can trigger autophagy. There's other mechanisms. There's Beclin 1 mechanisms and so forth. But it's an interesting set of experiments to do with a young group of patients and an old group of patients.

    30. PAPeter Attia1:46:46

        And there's a priming effect to this that I just don't-- I mean, it's so multifaceted to study all of these things. You think of the infinite combinations you can have, which is what's the effect of rapa plus fasting when staggered, for example?

12. 1:47:00 – 1:56:15

    Excitement around RTB101—resTORbio’s mTOR inhibiting molecule

    1. PAPeter Attia1:47:00

       Does one prime the other? It's hard. You can't really go on fishing expeditions with these questions. You have to be more thoughtful in your hypothesis generation. There's just too many variables.

    2. LKLloyd Klickstein1:47:10

       That's right.

    3. PAPeter Attia1:47:10

       There's too many ways to be fooled.

    4. LKLloyd Klickstein1:47:11

       That's right.

    5. PAPeter Attia1:47:13

       So what can you tell us now about RTB101? What has been published on this? In other words, I don't think we can speak about obviously anything that's not published at this point, or at least hasn't been publicly signaled.

    6. LKLloyd Klickstein1:47:22

       Yeah.

    7. PAPeter Attia1:47:22

       What's next for this compound?

    8. LKLloyd Klickstein1:47:24

       So the excitement is in the Phase 2a study that Novartis ran, we saw decreased respiratory tract infections in elderly people treated with it. In the Phase 2b study that resTORbio ran, again, the same dose, 10 milligrams once a day, saw the same thing, a decrease in respiratory tract infections. Now, that study was a complicated study.

    9. PAPeter Attia1:47:46

       And did it also have an RTB101 plus RAD001 arm?

    10. LKLloyd Klickstein1:47:52

        It did, and there was not a decrease in respiratory tract infections there.

    11. PAPeter Attia1:47:56

        But there was an increase in immunity? Or was that-- That was a secondary outcome.

    12. LKLloyd Klickstein1:48:00

        That was assessed, but it hasn't been talked about yet. The cool thing about the 2018 paper that was published from the Novartis study is that because we saw a decrease in respiratory tract infections, but we did not see an increase in vaccine response, it told us that the mechanism for the decrease in respiratory tract infections had to be something different. And we had collected some samples for exploratory profiling. We learned that there was an upregulation of antiviral gene expression in peripheral blood leukocytes. So a set of interferon-stimulated genes responsible for antiviral activities was upregulated. So we identified a candidate mechanism, and it makes a lot of sense.

    13. PAPeter Attia1:48:50

        So to put that in English, it's not that the response was mediated by better recognition of viruses. It was mediated by more efficient targeting of and/or disposing of viruses?

    14. LKLloyd Klickstein1:49:03

        Perhaps another way to say it is that the vaccine response we were measuring as the primary endpoint was a lymphocyte-acquired immunity measurement. So in other words, you're immune to flu because you've been vaccinated. If you've been vaccinated for rabies, you're immune to that. I've never been vaccinated for rabies. I'm not immune to rabies. In contrast, there's something called innate immunity, which is the immunity of our species This is an immunity that was developed because we have all co-evolved with our pathogens, and those of us who are here

    15. PAPeter Attia1:49:40

        Yeah, this is why the LPS on strep is you don't need to be vaccinated to recognize it.

    16. LKLloyd Klickstein1:49:45

        Exactly. So there are many, many, many, many other things that we can recognize, elements of pathogens, so we can mount an effective immune response, and we're born with this. We don't have to be immunized for it. And this part of the immune system is what mTOR inhibition can also activate.

    17. PAPeter Attia1:50:04

        Yeah, which is, to go back to historical, that's not what we care about in transplant.

    18. LKLloyd Klickstein1:50:09

        No.

    19. PAPeter Attia1:50:09

        'Cause in transplant, you certainly didn't-- We didn't evolve to reject kidneys. We evolved to accept our kidneys.

    20. LKLloyd Klickstein1:50:15

        [chuckles]

    21. PAPeter Attia1:50:16

        Therefore, we reject someone else's kidney. That's MHC based.

    22. LKLloyd Klickstein1:50:20

        Right, right. Although blood type matching of your organ transplants is for-

    23. PAPeter Attia1:50:24

        Well, that's true, and now they're doing so many ABO incompatibles that it's-- I mean, the immunology involved in organ transplantation today is remarkable.

    24. LKLloyd Klickstein1:50:32

        A subject for another time.

    25. PAPeter Attia1:50:33

        I know, and all started at your alma mater. That was the Nobel Prize right there, right?

    26. LKLloyd Klickstein1:50:36

        That's right.

    27. PAPeter Attia1:50:37

        Dr. Murray. So is there anything else you can tell us? 'Cause this is obviously something like have you guys spoken about what the phase three is going to look like?

    28. LKLloyd Klickstein1:50:45

        Yeah. Well, we're almost halfway through.

    29. PAPeter Attia1:50:48

        Halfway through enrollment.

    30. LKLloyd Klickstein1:50:49

        We enrolled the first phase three study fully and getting ready to start the second.
13. 1:56:15 – 2:00:00

    Identifying rapalogs selective for TORC1

    1. PAPeter Attia1:56:15

       that 10 milligrams is not too high that you're willing to give them the drug during flu season or during winter cold season.

    2. LKLloyd Klickstein1:56:22

       Yes.

    3. PAPeter Attia1:56:23

       All right. So let's turn over to something else you brought up earlier, which was the, the Laming paper that came out about two months ago. That's a prolific lab. Laming was a postdoc in David's lab, so no stranger to this science. There are lots of folks out there that are working on selective mTORC1 inhibition, notwithstanding the potential ways around it through intermittent dosing or looking at catalytic binding or things that might be-- offer you a little bit more insight. What is your take on the biochemistry of selective binding and selective inhibition, more specifically? The binding is quite selective.

    4. LKLloyd Klickstein1:57:02

       Yeah. I thought basically to summarize that paper for the listeners, the Laming Group looked at, I think it was 90 different rapalogs, presumably related to rapamycin, and looked for their ability to be selective for TORC1, even with more sustained exposure. Then they identified a couple that were, and they-- most of the paper was on one that they liked the best. The really cool thing, and this is gonna get us into an immunophilin discussion, is that they found possibly the reason the compound was selective was that it bound to one of the immunophilins but not another. So specifically, it bound to FKBP12, or at least FKBP12 was required for the compound to have activity. But another FKBP, FKBP51, was not.

    5. PAPeter Attia1:58:00

       But I still don't understand this. If you bind to FKBP12 and then the rapalog plus FKBP12 binds to mTOR, don't you still get into the same problem where after a long enough period of time, you don't have enough TOR to make complex two?

    6. LKLloyd Klickstein1:58:19

       I don't think that's why complex two is inhibited.

    7. PAPeter Attia1:58:22

       What do you think rapamycin specifically is doing to inhibit complex two then?

    8. LKLloyd Klickstein1:58:26

       I think it's a downstream and indirect sort of counter-regulatory signaling mechanism.

    9. PAPeter Attia1:58:32

       I see. So it has to do more with sort of the serine kinase or the 4E-BP1 or something like that. Like something downstream of a direct phosphorylation is counter-regulating or-

    10. LKLloyd Klickstein1:58:44

        Yes.

    11. PAPeter Attia1:58:45

        Yeah. I see. And you're saying presumably, if you only bind a rapalog to FKBP12, you somehow don't hit that target?

    12. LKLloyd Klickstein1:58:54

        Well, I think what their data say is because the compound that they show has no TORC2 activity at all, does not bind to FKBP51, or at least that's the implication, because downregulating FKBP51, which I think they did with an siRNA, had no effect on its inhibitory activity, suggests that there's a complexity to the complexes formed, sorry for that, that we don't yet understand, and it's an exciting area to explore. So remember, every cell has many immunophilins in it. It has several cyclophilins. It's got several FKBPs, so FKBP12, 51, and 52 are probably the big three, but there are a few others.

    13. PAPeter Attia1:59:41

        By the way, I thought RAPA only bound to 12. RAPA binds to what?

    14. LKLloyd Klickstein1:59:45

        They showed that it binds to at least 12 and 51.

    15. PAPeter Attia1:59:49

        Okay. I mean, that's amazing. I had always thought that RAPA binds only to FKBP12, which then binds to TOR. I didn't even realize it was binding to 51.

    16. LKLloyd Klickstein1:59:59

        So we know

14. 2:00:00 – 2:03:30

    Treating depression with ketamine, an activator of mTOR

    1. LKLloyd Klickstein2:00:00

       it binds to 51 in their paper, and there have been some other papers studying the ryanodine receptor that show that it binds to 12.6 also, which is in cardiac myocytes.

    2. PAPeter Attia2:00:10

       We've talked all about inhibition. Are there any times when you wanna be activating this? There's a lot of talk that ketamine may be activating mTOR, and obviously ketamine has some really interesting properties as it pertains to recalcitrant depression.

    3. LKLloyd Klickstein2:00:26

       Yeah. So two points here. For patients with major depression, intravenous ketamine is almost a miracle drug. We're accustomed to typical antidepressive drugs requiring weeks and weeks to work and having modest effects at best.

    4. PAPeter Attia2:00:46

       Or even days, but this is minutes.

    5. LKLloyd Klickstein2:00:48

       Ketamine works in minutes to hours.

    6. PAPeter Attia2:00:50

       Yeah.

    7. LKLloyd Klickstein2:00:51

       And a huge effect size. It's really amazing. I don't think we know what the specific cellular mechanism is of that, 'cause I'm giving you lots of things we don't know in our discussion.

    8. PAPeter Attia2:01:03

       Wasn't there a study that showed rapamycin blocked the effect of ketamine?

    9. LKLloyd Klickstein2:01:08

       Yes, and there's a biotech company called Navitor.

    10. PAPeter Attia2:01:12

        I know them well.

    11. LKLloyd Klickstein2:01:13

        And they're using an mTOR activator to treat depression.

    12. PAPeter Attia2:01:17

        Their Lloyd equivalent is also a very smart guy, so I, uh-

    13. LKLloyd Klickstein2:01:20

        [chuckles] Who?

    14. PAPeter Attia2:01:21

        George is, uh-

    15. LKLloyd Klickstein2:01:22

        Yes.

    16. PAPeter Attia2:01:22

        Yeah, George is fantastic.

    17. LKLloyd Klickstein2:01:24

        Yeah.

    18. PAPeter Attia2:01:24

        So Lloyd, is this a relatively recent understanding then about how RAPA is binding to the FKs and how it's-

    19. LKLloyd Klickstein2:01:33

        Yes

    20. PAPeter Attia2:01:33

        ... the, the complexity around, first of all, how many of these things there are and how you can change their properties by which ones you're binding to?

    21. LKLloyd Klickstein2:01:40

        Yeah. So it's something that's not discussed a lot in the literature, but there are several FKBPs or FK506 binding proteins. We almost always talk about FKBP12, and it's sort of a shorthand, but the understanding has been that rapamycin binds to all of them. In a few specific cases, that's been shown to be true. There's also a bunch of other activities for, and roles for FKBPs that aren't at all part of TORC1 biology. For example, they all have an enzymatic activity. They're peptidyl prolyl isomerases. But what the biology of that is remains pretty much unclear. It's a very interesting enzymatic activity. It's involved in protein folding, but there have been some studies where maybe a dozen different of these immunophilins are completely eliminated at the same time from cells. There was no clear cellular phenotype. So whether that means the others can all substitute because it's such a critical function or they have no function that's important.

    22. PAPeter Attia2:02:47

        Are there disease states where people are lacking any of these?

    23. LKLloyd Klickstein2:02:52

        There may be, but I don't know them.

    24. PAPeter Attia2:02:53

        And how conserved are they across species?

    25. LKLloyd Klickstein2:02:56

        Highly conserved. These immunophilins are present in almost all species, although they can vary a little bit.

    26. PAPeter Attia2:03:03

        Is there any cell in the body that does not contain mTOR?

    27. LKLloyd Klickstein2:03:07

        I would bet some of the terminally differentiated anucleate cells may not.

    28. PAPeter Attia2:03:12

        Red blood cells, for example, do?

    29. LKLloyd Klickstein2:03:15

        Certainly, red blood cell precursors do.

    30. PAPeter Attia2:03:17

        Mm-hmm.
15. 2:03:30 – 2:14:54

    Epigenetic clocks, rapalogs, and metformin

    1. PAPeter Attia2:03:30

       Well, I'll make sure David listens to this, and you know what? Maybe we'll do an AMA with David specifically on TOR. So last thing I want to chat about, because it, the paper came out kind of recently, was this sort of interesting paper. It's interesting not in the sense of the intervention because it was an N of nine, and it was a very poorly controlled study in the sense that there was no placebo group, and every patient actually was on their own sort of tailored cocktail of three different drugs or two hormones and a drug. But the paper did get a lot of press because it used an epigenetic clock. Are you familiar with these clocks?

    2. LKLloyd Klickstein2:04:02

       Yes. Yeah. This is Horvath's work, right?

    3. PAPeter Attia2:04:04

       Yeah. Yeah. Horvath's probably the best of these clocks. Maybe just as a little bonus episode, tell folks how these things work, what they're measuring. We've already talked a little bit about methylation, so maybe we put a bow on this by discussing that.

    4. LKLloyd Klickstein2:04:18

       So I forget how many years ago it was now, but it wasn't that many, that we learned from Horvath and others that by looking at the methylation pattern on peripheral blood leukocyte DNA, we can tell how old you are within about six months to a year, and this has been replicated by several groups. So we're all familiar with DNA and-

    5. PAPeter Attia2:04:44

       And that's even true among centenarians and people that are just genetically blessed to live longer?

    6. LKLloyd Klickstein2:04:50

       Excellent question. The studies that I've seen, and actually the one that we participated in, I don't think we had people over 80.

    7. PAPeter Attia2:04:58

       Mm-hmm. Okay.

    8. LKLloyd Klickstein2:05:00

       I don't know the answer to that. But for people between about 20 and 80, there's a stereotypical change in methylation patterns on DNA, and this is just a chemical change to DNA that happens over time that's quite characteristic of your chronologic age.

    9. PAPeter Attia2:05:20

       This is the what David Sinclair talks about as sort of the scratching of the CD.

    10. LKLloyd Klickstein2:05:23

        [laughs]

    11. PAPeter Attia2:05:25

        The CD being the master copy of your genomic-

    12. LKLloyd Klickstein2:05:28

        Yeah, I guess we have to say something like that because we can't use wearing out of the vinyl anymore.

    13. PAPeter Attia2:05:32

        [laughs]

    14. LKLloyd Klickstein2:05:34

        But I think about it a little differently. I think about aging fundamentally as a biologic process controlled by pathways, and presumably, it's a consequence of changes in gene expression, and this methylation changes gene expression. So it's a pretty cool story. And certainly, we know that if you take a differentiated cell and treat it with a set of transcription factors called the Yamanaka factors, you can reset the cell back to a pluripotent stem cell, and the methylation goes away, too. So I'm thinking that DNA methylation likely could be causally related to the expression, gene expression changes that not only are associated with aging but may cause aging.

    15. PAPeter Attia2:06:25

        So has anybody looked at the effect on the Horvath clock or DNA methylation in response to the rapalogs we've been discussing today?

    16. LKLloyd Klickstein2:06:35

        I'm thinking of one experiment, but I don't know that it's published yet, and I think the answer was negative.

    17. PAPeter Attia2:06:40

        So it's interesting because the paper that I was talking about, again, there are 10 ways to Sunday. This could just be an outlier, especially without a control group. I mean, it's really difficult to make any conclusion. But if any of this benefit was real, which was growth hormone, DHEA, and metformin set the Horvath clock back, I think it was a year and a half or two and a half years. The initial hypothesis of the experiment was that this was going to improve thymic function, which was going to improve immune function. Doesn't seem like a stretch that you could potentially see that benefit from a rapalog if it's also acting on immunity, which is why I think I was sort of-- That's probably why I asked about the thymus in the past.

    18. LKLloyd Klickstein2:07:25

        Yeah. So I have a few comments about this. One is, first, DHEA, we know goes down substantially with age, but there have been several to many studies of replacing it, and there's no clinical benefit.

    19. PAPeter Attia2:07:40

        And I think the author used it for the effect of reducing the hyperinsulinemia that follows the administration of growth hormone. And in his, I think, personal experience taking growth hormone noted that he could blunt the hyperinsulinemia by taking something like 50 milligrams of DHEA by itself. But again, I've-- that's not something that's well documented in the literature. And your point, of course, is documented, which is DHEA by itself, you can fix the number, but that doesn't seem to have any clinical bearing.

    20. LKLloyd Klickstein2:08:10

        Exactly. My second point is the growth hormone, the biologic activity of it is mostly driven, not exclusively, by IGF-1, which used to be called, I think, somatomedin when we were in medical school. We know that lymphoid tissue is probably the most sensitive target organ for IGF-1, and it causes hypertrophy. So if he's looking for enlarged thymus in patients he's treating with growth hormone, I would be surprised if you did not see that.

    21. PAPeter Attia2:08:49

        And he did. And so the question is, wouldn't you have expected that to have sped up growth?

    22. LKLloyd Klickstein2:08:55

        I would have expected, if he treated long enough, I would have expected to increase the size of the thymus if he could find it in people.

    23. PAPeter Attia2:09:02

        I believe the study looked at MRI and showed an increase in thymic size. They were treated for a year, I believe.

    24. LKLloyd Klickstein2:09:09

        Not surprised at all. I bet the spleen increased too.

    25. PAPeter Attia2:09:12

        Is there any reason to believe that that would enhance immune function?

    26. LKLloyd Klickstein2:09:17

        I'm thinking if I've read a paper about that and I don't know.

    27. PAPeter Attia2:09:21

        And then what about the metformin wrench in the works?

    28. LKLloyd Klickstein2:09:24

        [chuckles] Metformin's a really interesting compound. I think we have excellent data that in diabetics it is a wonderful drug. And there's some retrospective data of longevity in diabetics treated for a long time with metformin. And of course, this is the question Nir Barzilai wants to answer with the TAME study.

    29. PAPeter Attia2:09:44

        Right. And Nir and I have spoken about this many times, and I agree that it's hard to make the case for a more beneficial agent in someone with diabetes or hyperinsulinemia metabolic syndrome or anything on that continuum, on that spectrum. Of course, the question is, what is the benefit of metformin in a perfectly healthy person or even a fully optimized person with respect to other variables?

    30. LKLloyd Klickstein2:10:08

        I'm not aware that there is a benefit of it. Remember, it has some adverse effects on mitochondrial function too, potentially.

Episode duration: 2:14:54