Circulation May 3, 2022 Issue

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.