May 2, 2022
This week, please join author Guest Host Mercedes Carnethon, Author Brian Bergmark, and Associate Editor Parag Joshi as they discuss the article “Effect of Vupanorsen on Non–High-Density Lipoprotein Cholesterol Levels in Statin-Treated Patients With Elevated Cholesterol: TRANSLATE-TIMI 70.”
Dr. Carolyn Lam:
Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to the journal and its editors. We're your co-host. I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center in Duke National University of Singapore.
Dr. Greg Hundley:
And I'm Dr. Greg Hundley, Associate Editor, Director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Well Carolyn, this week's feature, non-high density lipoprotein cholesterol levels in statin treated patients with elevated cholesterol. We're going to hear from the TRANSLATE-TIMI 70 study. But before we get to that, how about we grab a cup of coffee and discuss some of the other articles in the issue? Would you like to go first?
Dr. Carolyn Lam:
I would. And by the way, that feature is going to be all exciting. It was discussed at the American College of Cardiology. But okay, how about from cholesterol to vitamins? Let's start with the Greg quiz. Greg, which vitamins have been associated with arterial calcification? Is it A, B, C, D, E?
Dr. Greg Hundley:
I'm going to pick E and K.
Dr. Carolyn Lam:
You’re smart. Indeed. Vitamin K2, also known as menaquinone-7 is the most effective co-factor for the carboxylation of proteins involved in the inhibition of arterial calcification. Furthermore, combined low vitamin K and low vitamin D have been associated with increased all-cause mortality risk. And so, today's paper is from Dr. Diederichsen from Odense University Hospital in Denmark and colleagues really present the first double-blind, randomized controlled trial to test whether vitamin K2, a drug-targeting processes of calcification in addition to vitamin D, could slow the progression of aortic valve calcification and stenosis. So, in a randomized double-blind multicenter trial, men from the community with an aortic valve calcium score above 300 arbitrary units on cardiac non-contrast CT were randomized to daily treatment with 720 micrograms of vitamin K2 plus 25 micrograms of vitamin D or matching placebo for 24 months. And the primary outcome was the change in aortic valve calcium score.
Dr. Greg Hundley:
Carolyn, so menaquinone-7 and aortic valve score. So, what were the results?
Dr. Carolyn Lam:
Menaquinone-7 had no major effect on the progression of aortic valve calcification as assessed by CT or echo. High-dose menaquinone-7 was, however, safe and well tolerated. Now, some limitations is that this external validity is limited to men aged 65 to 74 with aortic valve calcification scores of greater or equals to 300 arbitrary units. Thus, caution is needed if we extrapolate these findings and other pathways need to be explored in order to identify an effective therapy for this unmet clinical need.
Dr. Greg Hundley:
Wow, very nice Carolyn. Well, my first article comes to us from Dr. Michael Laflamme from the University Health Network. And Carolyn, human pluripotent stem cell-derived cardiomyocytes or hPSC-CMs exhibit promise for application in cardiac regeneration, but their translational potential is limited by an immature phenotype. So Carolyn, this research team hypothesized that large scale manufacturing of mature hPSC-CMs could be achieved via culture on polydimethylsiloxane, and we're going to call that PDMS, lined roller bottles and that the transplantation of these cells would mediate better structural and functional outcomes then with conventional immature hPSC-CMs populations.
Dr. Carolyn Lam:
Oh, that's neat, Greg. So, what did they find?
Dr. Greg Hundley:
Right, Carolyn. So, these authors demonstrated the economic generation of greater than one times 10 to the eighth mature hPSC-CMs per PDMS line roller bottle. And compared to their counterparts, PDMS matured hPSC-CMs exhibited increased cardiac gene expression and more mature structural and functional properties in vitro. More importantly, intracardiac graphs formed with PDMS matured myocytes showed greatly enhanced structured alignment, better host graft electromechanical integration, less pro arrhythmic behavior, and greater beneficial effects on contractile function. So in summary, Carolyn, this team describes practical methods for the scale generation of mature human pluripotent stem cell-derived cardiomyocytes and provide the first evidence that the transplantation of more mature cardiomyocytes yields better outcomes in vivo. And there's a wonderful editorial by Professor Murray entitled Flexing Their Muscles: Maturation of Stems Cell-Derived Cardiomyocytes on Elastomeric Substrates to Enhance Cardiac Repair.
Dr. Carolyn Lam:
Wow! That's really significant. Thank you, Greg. Well, the next paper is the largest genome-wide association meta-analysis of plasma ACE2 levels in over 28,000 individuals. And this is from Dr. Xia Chen from Fudan University and Dr. James Wilson from University of Edinburgh in UK, and their colleagues. And guess what, it focuses on severe acute respiratory syndrome coronavirus 2, the etiologic agent of COVID 19. And we know that that enters human cells using the ACE2 protein as a receptor. ACE2 is thus key to the infection and treatment of the coronavirus. ACE2 is highly expressed in the heart, respiratory and gastrointestinal tracts, playing important regulatory roles in the cardiovascular and other biologic systems.
Dr. Greg Hundley:
Wow, Carolyn. ACE2, and also a very important topic here with SARS-COVID-2. So, what did they find?
Dr. Carolyn Lam:
First, the overall heritability of ACE2 level is 16% of which 30% can be explained by 10 protein quantitative trait loci identified in this study. ACE2 level is genetically correlated with both COVID-19 and cardiovascular. Elevated ACE2 levels show a causal relationship with COVID-19 severity, hospitalization and infection as shown by Mendelian randomization analyses. ACE2 regulatory variants are enriched on DNA methylation sites in immune cells.
Dr. Greg Hundley:
Wow, Carolyn. So, elevated ACE2 and a causal relationship with COVID-19 severity. So tell us, what are the clinical applications of this really nice study?
Dr. Carolyn Lam:
The causal evidence of ACE2 suggests that pharmacological inhibition of circulating ACE2 may be a promising approach for treating COVID-19 or its comorbidities. Transcription factors that play essential roles in ACE2 generation could provide alternative paths to pharmacological modulation of ACE2 plasma levels. The genetic correlations between ACE2 and both COVID-19 and cardiovascular disease imply that the cardiovascular complications seen in COVID-19 patients may be intrinsic to the disease and mechanically or/and mechanistically-driven by ACE2. Isn't that neat?
Dr. Greg Hundley:
You bet, Carolyn. Boy, what an exciting issue. And we've got other articles in this issue.
Dr. Carolyn Lam:
Yeah. Now, let me start this time. There's an exchange of letters between Drs. Duan and Chang regarding the article “Therapeutic Exon Skipping Through a CRISPR-Guided Cytidine Deaminase Rescues Dystrophic Cardiomyopathy in Vivo.” There's a Perspective piece by Dr. Morris, “The Updated Heart Failure Guidelines: Time for a Refresh.” Love that piece! There's an AHA Update piece (AHA President’s Page) by Dr. Elkin on The Road to Equity in Brain Health, and ECG challenge by Dr. Kolominsky, Electrical Extremists in a Critically ill Patient, and an On My Mind Paper by Dr. Paulus entitled “Border Disputes Between Heart Failure Phenotypes.”
Dr. Greg Hundley:
Wow, Carolyn. And I've got two Research Letters. The first from Professor Groeneveld entitled “Prevalence of Short-Coupled Ventricular Fibrillation in a Large Cohort of Dutch Idiopathic Ventricular Fibrillation Patients.” And then a second Research Letter from Professor Yamashita entitled “Single Cell RNA Sequence Reveals a Distinct Immune Landscape of Myeloid Cells in Coronary Culprit Plaques Causing Acute Coronary Syndrome.” Well Carolyn, now, we get to go onto our feature, vupanorsen on non-high-density lipoprotein cholesterol levels and catching up with TIMI 70.
Dr. Carolyn Lam:
Let's go.
Dr. Mercedes Carnethon:
So, good morning listeners. I'm really pleased to invite you to this episode of our Circulation on the Run podcast. For those of you who don't hear me often, I'm stepping in as a guest host today. My name is Mercedes Carnahan from the Northwestern University Feinberg School of Medicine. And I'm really excited to be joined today by Dr. Brian Bergmark, and associate editor, Dr. Parag Joshi. And we will have today Dr. Bergmark discussing his new article published with us on the effects of vupanorsen on non-HDL cholesterol levels in the TRANSLATE-TIMI 70 trial. We're really thrilled to have you with us here today, Brian, to talk about the really important findings coming from this trial. So to start us off, just tell us, what did you find?
Dr. Brian Bergmark:
Great. Thank you so much. It's really a pleasure to be here and I'm grateful for the opportunity. So, in the big picture, despite numerous agents to reduce lipid-mediated cardiovascular risk, obviously, residual risk remains and there are novel targets to address that risk. One of them is angiopoietin-like 3, which is a protein made in the liver. Angiopoietin-like 3 or ANGPTL3 inhibits lipoprotein lipases among other lipases, and thereby interferes with metabolism of triglyceride-rich lipoproteins. And so, the idea here was that if ANGPTL3 could be inhibited that LPL or lipoprotein lipase function could be augmented and metabolism of these lipoproteins could be augmented. And so, what we did is we took patients with an elevated non-HDL cholesterol, at least 100 milligrams per deciliter, and elevated triglycerides, 150 to 500 milligrams per deciliter, and randomized them to placebo or one of seven doses of vupanorsen, which is an antisense oligonucleotide, which inhibits the synthesis of ANGPTL3 in the liver. We then follow them to see what the impact was on their non-HDL cholesterol, as well as other lipid parameters through 24 weeks.
Dr. Mercedes Carnethon:
Thank you so much. It's a wonderful design, and I'm really excited to hear a little bit more about what you found.
Dr. Brian Bergmark:
Great. So, the primary endpoint was the change in non-HDL cholesterol from baseline to 24 weeks. And we did find that all vupanorsen regimens reduced non-HDL cholesterol in a statistically significant manner. The magnitude of that effect was up to 27.7% in one of the dose arms or about 28%. We also saw a statistically significant reductions in the target ANGPTL3 up to about a 95% reduction in the highest dose arm, as well as statistically significant reductions in triglycerides at all of the dose regimens. The effect on LDL cholesterol and on apolipoprotein B or apo B was variable across regimens and only statistically significant in a few of the dose arms. We also found several safety signals. One, there appeared to be higher rates of injection site reactions in the skin at higher total monthly doses. We also found higher rates of elevation in liver enzymes, AST and ALT at higher total monthly doses. And we also found significant increases in hepatic fat fraction or the fat content of the liver at higher total monthly doses.
Dr. Brian Bergmark:
In the end, we found that while statistically significant, the magnitude of the reduction in non-HDL cholesterol was modest as was the reduction in apo B. And so, the goal here was to find a dose that might have a reduction of a magnitude that would be clinically meaningful for cardiovascular risk reduction. We were underwhelmed by the magnitude of that reduction, and then it was paired with these safety signals, which if there's interest, we could get into more detail in our thinking about why those occurred, what the implications are, but suffice it to say that there were medically meaningful safety concerns paired with a modest reduction in non-HDL cholesterol.
Dr. Mercedes Carnethon:
Thank you for that excellent summary. Before I turn it over to the associate editor, I read this with great interest, and in particular, looking at one of the first figures in the paper, which is demonstrating the adjusted change at 24 weeks across different doses and based on how frequently the doses were given the four week as compared with the two week. And one thing that really stood out to me was the clear dose response with the four week regimens with the higher doses appearing to demonstrate the greatest reductions but a less clear signal with the two week regimens. Do you have any hypotheses about why these patterns appeared so different?
Dr. Brian Bergmark:
Yeah. It's a great question. So, the responsiveness of this is something of interest here I think. So, if you look at the effect of the drug on its target, ANGPTL3, there is a very clear dose response, so there's no doubt that higher doses were impacting the target ANGPTL3 to a greater extent. So, one of the most direct effects would be on triglycerides, one of the most direct lipid effects, and that appears pretty close to a dose response relationship within each of these frequencies of administration. But once you start getting to non-HDL cholesterol, it starts to break down a bit. And is it simply because of random chance or is there actually something distinct going on with how the lipids are being metabolized?
Dr. Brian Bergmark:
That is something we are diving into. So, the hope would be that we actually reduce apo B, the number of these actually circulating lipoproteins as has been demonstrated with the monoclonal antibody. It's possible that with this other different mechanism in the antibody, this antisense oligonucleotide, perhaps, we're simply shifting the content of these lipoprotein molecules and decreasing the triglyceride content but not actually meaningfully modifying the amount of apo B, LDL cholesterol. And that might be part of what we're seeing with the more muted relationship between dose and the effect on non-HDL cholesterol. I don't know for certain we are diving into this a bit more with other lipid fractions, et cetera.
Dr. Mercedes Carnethon:
Oh, well, thank you so much for that explanation. I know that a number of people, this was extremely well received when shared at the recent American College of Cardiology meetings, and so I was really thrilled to find that this was appearing in the journal circulation. So Parag, I'm really interested in hearing your perspectives on why we knew that this was certainly a priority paper for us.
Dr. Parag Joshi:
Yeah. Let me first start, Brian, congratulations. Fantastic work. And we were excited to receive the paper. I think really hard to pull off trials right now or in the last couple years, so kudos to you. And I echo the sentiments from Mercedes. This is great work. Really important space, the residual risk space I think is very important of course and is critical to moving forward with improving cardiovascular health. So, one of the big picture questions and as we get to this triglyceride-rich lipoprotein lowering space, certainly, there's strong associations with residual risk, but can we impact that risk? And here, we're starting to explore that. And I think when you think of the lipoprotein space, many of us are interested in what is the effect on these lipoproteins as opposed to the cholesterol content or the triglyceride content. And non-HDL cholesterol or apo B, clearly, the better, stronger markers for that risk, so we were really excited to see this paper.
Dr. Parag Joshi:
And as Brian mentioned, unfortunately, not the strongest impact here on those measures. And I want to dive into that a little more because I think that carries significant implications for the space, and I'd love to hear your thoughts on that. But overall, really fantastic work. I think my first question really is around the apo B aspect of this and the less than anticipated lowering of those levels. You hinted at this in terms of, is this shuffling cholesterol and triglycerides across particles, or do you think this could be the mechanism by which this happens through ANGPTL3? You do inhibit the levels quite a bit. Did we just miss that... Is this not the right target? What do you think?
Dr. Brian Bergmark:
Yeah, it's a great question. I do think the target itself holds great promise. Obviously, a monoclonal antibody against this same target results in major reductions in apo B, LDL cholesterol, and the latter through a mechanism that is not really known but is not dependent on the LDL receptor, and therefore has real clinical utility that's approved for people with familial homozygous hypercholesterolemia. Beyond that, of course, in genetic studies, there's a clear association with loss of function in the ANGPTL3 gene and lower levels of all of these lipids, lower rates of coronary artery disease, et cetera.
Dr. Brian Bergmark:
So, I think it's not that this pathway is not promising and actually already being taken advantage of, I think it's that this particular agent acting through this mechanism was not able to achieve a necessary efficacy with reasonable safety. Some genetic data suggests that there is not actually a dose response between a reduction or loss of function in ANGPTL3 and reduction in apo B or lower levels of apo B and non-HDL cholesterol, but it really requires your complete elimination of ANGPTL3 function, which is probably, likely achieved with the monoclonal antibody. And so, even though we had quite large reductions with the antisense oligonucleotide, perhaps, we just didn't cross that threshold that's needed to modify the lipid panel in the way that would've been clinically meaningful.
Dr. Parag Joshi:
Yeah. I think that's fantastic as you allude to with evolocumab and the impact that has on apo B levels. I didn't think of it as a threshold effect, but that makes a lot of sense as maybe that just getting to that tipping point is where the issue is here. In terms of the liver signal, what were your thoughts on that? And is that something that we should expect to see in ASOs or do you think it's specific to this compound?
Dr. Brian Bergmark:
Yeah, I don't know. That was unexpected. Right, there are two liver signals and it's unclear how related they are. One is the inflammation of the liver as indicated by the elevation in enzymes, and then the other is the fat accumulation. So with respect to the fact, if anything, genetic data suggests perhaps loss of function in ANGPTL3 might result in lower rates of hepatic steatosis. In animal models, the antisense oligonucleotide reduces liver fat, and so there's, there was promise going into this that this could actually be beneficial for non-alcoholic fatty liver disease. And additionally, there's not data to suggest that the monoclonal antibody increases liver fat. So, there's not a lot to support this as being an on-target effect that by inhibiting ANGPTL3, by that pathway, the liver fat was increased. So, I think a reasonable person might wonder whether this was an off-target effect of the drug.
Dr. Brian Bergmark:
By what mechanism that occurred, I don't know, what the implications would be for other related agents, I don't know. And then similarly, the liver enzyme elevations, is that related to this? I'm not exactly sure, but also unexpected and I think off-target. But that sort of intrinsic to this mechanism of hepatic targeting, is this something we need to be worried about for other agents in this class or not? I don't know. Obviously, we can't answer that from this single study. We are going to dive into it a bit more to try to overlay patients with hepatic fat accumulation, liver enzymes, et cetera. Of course, both of those happen more at higher doses. How much we can really parse this? I'm not sure yet.
Dr. Parag Joshi:
Yeah. That's really fascinating. I think the appeal of this paper to the circulation audience is that you have a really exciting novel target and pathway to explore here but somewhat divergent results from what's existing in this space. And I think that raises a lot of questions, really interesting questions going forward for this space. For the ANGPTL3 pathway, what do you see there coming down the line or what are your thoughts on that going forward for this target and ways to approach risk related to it?
Dr. Brian Bergmark:
Yeah. Great. Thank you. Yeah. No, so I agree. I think moving into this other end of the spectrum of triglyceride-rich lipoproteins, et cetera, I think this is where we're headed and this is why we do the trial. We weren't expecting these things that's why you do this experiment, and this is what we found. So now, where do we go from here? So there are, of course, other ways beyond the monoclonal antibody of targeting ANGPTL3 specifically. There's siRNA, there is gene therapy being investigated. So, I think all of them hold an great promise. And of course, we will need to see as those therapies move along what the actual trials show. And then there are, of course, other pathways that are of interest, APOC3, for instance. So, I think there's a lot more in this space that's coming down the line.
Dr. Parag Joshi:
Yeah, absolutely. I think it's a really exciting space, and we're really happy to get this paper as one piece of that whole puzzle. So, thank you.
Dr. Mercedes Carnethon:
Yes. And I echo that as well. And as a methodologist myself, I'm always really pleased to see such well-designed studies. I think this was sophisticated in many aspects in testing different dosing and different timing of the dosing. And also, I'm really impressed by your inclusion criteria, particularly when I noted that 44% of the participants were female, and that you reported those stratum-specific effects. I just had a final question as we wrap up. You acknowledge a nominally significant interaction by sex and I see, for example, that it appears that the magnitude is larger possibly in the relatively smaller subset of females as compared with males. Is this something to pay attention to or do you think this is just some type of an artifact related to greater variability because the group is smaller?
Dr. Brian Bergmark:
Yeah, it's a good question. So, this is the burning question. We had no a priority reason to suspect that biologically and we are not adjusting for multiple testing in the key value of 0.04. So just to put my money down, I would say, I would guess it's random chance. We found it. It's worthy of looking into a bit more. There were, of course, the important implications for other drugs, et cetera. So, I think it's worth diving into as we will, but are we likely to uncover some biological difference? I doubt it. I wouldn't guess. There are other subgroups where I think at least upfront, you might expect there could be a difference. So, there are thoughts about insulin's effect on LPL. Could diabetes status have an interaction with the drug? I think though not statistically significant, it's also something worth looking into that group and the subfractions of the lipid panel and all of that stuff. So, I think it's all worth looking into but cautiously with the constraints.
Dr. Mercedes Carnethon:
Well, thank you so much for that explanation. And I've really enjoyed this discussion with you today, Brian, and you, Parag. I've certainly learned a lot and I'm really excited to see this excellent work coming out in the journal circulation. So, thank you very much for your time this morning and thank you to our listeners. Wrapping up this episode of Circulation on the Run.
Dr. Greg Hundley:
This program is copyright of the American Heart Association 2022. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association. For more, please visit ahajournals.org.