COMMENTARY

Top Trials Presented at TCT

Prof Mamas Mamas

Disclosures

October 07, 2019

This transcript has been edited for clarity.

Hi, my name is Professor Mamas Mamas. I'm professor of cardiology at Keele University. And today on behalf of Medscape UK, I'm going to talk about the most interesting trials presented at Transcatheter Cardiovascular Therapeutics (TCT) 2019 in San Francisco.

This was a big meeting. This was a meeting around 'less is more'. A meeting around shortening dual antiplatelet therapy, or studying outcomes in abbreviated antiplatelet therapy in different patient populations.

Onyx ONE

The first trial I want to talk about is the Onyx ONE trial. We know that patients at high bleeding risk of complications are increasingly encountered in our clinical practice and these patients are often very challenging to treat, because of their increased risk of ischaemic complications, as well as bleeding complications.

The Onyx ONE randomised controlled trial took 2000 such patients with high bleeding risk and randomised them, either to the Resolute Onyx (Medtronic) platform versus the BioFreedom (Biosensors) platform.

The primary outcome measured at 1 year was cardiac death, MI, or stent thrombosis. And this was a non-inferiority trial.

The main findings were the ONYX stent was non inferior to the BioFreedom stent. The event rate was 17.1% for the primary outcome at 1 year for the Onyx stent and 16.9% for the BioFreedom stent. Therefore, it was non-significantly different. Worrying though, most of the events at 1 year were driven by MI and the rates were around 15%. And even more worryingly, in both groups, the stent thrombosis rates were 2%. So whilst the Onyx platform is not inferior to the BioFreedom platform, these are very high stent thrombosis rates and really does make one pause for thought.

Should we be only using 1 month dual antiplatelet therapy regimes in these high risk patient groups? Or perhaps we could maybe even prolong antiplatelet regimes to maybe 3 months and see whether that impacts on patient outcomes.

Whatever we decide, what this study does tell us is that these patients are at very high risk of complications.

TWILIGHT

The next trial that has looked at antiplatelet regimes is the TWILIGHT trial. This was a randomised controlled trial, randomising patients at high risk of ischaemic or bleeding complications. And these were defined by a number of different categories. So for example, they were defined by being diabetic, age over 65, complex coronary disease, such as bifurcations, stents over 30 mm, and so forth. They were randomised to two different regimes: either ticagrelor (Brilique - Brilinta in the US, AstraZeneca) and aspirin for 12 months, or ticagrelor and aspirin for 3 months, followed by ticagrelor alone for the remaining time.

This was a large study of over 7000 patients. The primary outcome was BARC 2, 3, or 5 bleeding. )BARC is a bleeding grading scale developed by the Bleeding Academic Research Consortium).
What they found was a 40% reduction in the primary end points of BARC 2, 3, or 5 bleeding in those patients randomised to only 3 months of ticagrelor plus aspirin followed by the remaining time on ticagrelor alone.

The ischaemic outcomes were very similar - 3.9% in both groups. Interestingly, even if you don't count minor bleeds, and only look at BARC 3 to 5 bleeds, there was a reduction in 50%.

I think this trial is interesting. I think the bigger questions would be what would happen if there was an aspirin alone arm, so 3 months of ticagrelor and aspirin, followed by aspirin alone. I think that would be a very interesting analysis.

IDEAL LM

The third trial that again looked at abbreviated antiplatelet regimes was the IDEAL LM left main stem [left main coronary artery disease] study.

This was a study involving patients undergoing PCI (percutaneous coronary intervention) to the left main [coronary artery], who were randomised to a platinum-chromium Synergy platform (Boston Scientific), which has a bioabsorbable polymer and also Xience (Abbott Vascular).

The antiplatelet regimes were either 4 months in the Synergy arm, or 12 months in the Xience arm.

So in effect, you're testing two different platforms with two different antiplatelet regime durations.

Again, this was a non-inferiority trial. Looking at the primary endpoint of all-cause mortality, MI, and target vessel revascularisation, non-inferiority was met. Therefore the events at 1 year with the Synergy platform were 14.6% and for the Xience platform it was 11.4%.

However, worryingly, I would say, stent thrombosis and myocardial infarction were doubled, albeit not significantly, in the Synergy arm. So we have to ask ourselves, would we really only treat patients undergoing complex PCI for left main disease with only 4 months dual antiplatelet therapy?

I think with the results of this trial, it would be a very brave individual that would do so, and certainly my practice will remain treating such patients with 12 months dual antiplatelet therapy.

I think in patients that are high bleeding risk, and where there is a need to reduce antiplatelet duration, then perhaps this may be an option, but for the vast majority of patients, certainly with this propensity towards the doubling of stent thrombosis rates and re-infarction, I think 12 months should be the standard.

SCOPE

The final study that I want to talk about today is the SCOPE study. This was a randomised controlled trial between two different TAVR platforms in patients with severe aortic stenosis.

This was a trial of 739 patients randomising the Acurate Neo valve (Boston Scientific) versus the SAPIEN 3 valve (Edwards Lifesciences).

This was really quite an interesting trial, certainly from the outcome. It was powered to show non-inferiority, but actually the primary outcome wasn't met. The Acurate Neo platform didn't reach non-inferiority. In fact, the SAPIEN 3 Edwards valve was superior.

The event rates for this composite endpoint, which was quite a lot larger, with different types of clinical conditions, was 23.7% in the Acurate Neo arm and 16.5% in the SAPIEN 3 Edwards arm.

And the difference in the endpoints was mainly driven by moderate to severe para-valvular regurgitation and stage 2 to 3 kidney injury.

More Questions to Answer

Overall, there was a lot of interesting data at TCT 2019, and a lot of interest around trying to abbreviate dual antiplatelet therapy in high-risk patients undergoing PCI.

From my perspective, there is increasing evidence in this space, but I think what the conference shows is, there's still a lot more questions to be answered, particularly when many of these trials are focused around bleeding endpoints, but perhaps not powered to look at statistically significant differences in ischaemic endpoints.

Thank you for joining me in this podcast around what were the interesting trials in TCT 2019. And I look forward to hearing from you what you think were the highlights of the meeting.

Thank you.

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