Other important successes and equally important failures
Perhaps consideration of some of the treatments we didn’t have 20 years ago is more revealing than a list of advances. Two decades ago, there were no direct direct-acting anticoagulants on the market, “so no alternative to warfarin, which is difficult to use and associated with excess bleeding,” said Dr. Cannon. These days, warfarin is little used, mostly after valve replacement, Dr. Nissen added.
There were also no percutaneous options for the treatment of valvular heart disease and no catheter ablation of atrial fibrillation, “huge developments that are now being done everywhere,” Dr. Nissen said.
Also in the catheterization laboratory, there was also a far less sophisticated understanding of the optimal role of PCI in treating coronary artery disease.
“We’ve moved from what we called the ‘oculostenotic reflex’– if you see an obstruction, you treat it – to a far more nuanced understanding of who should and shouldn’t have PCI, such that now PCI has contracted to the point where most of the time it’s being done for urgent indications like ST-segment elevation MI or an unstable non-STEMI. And this is based on a solid evidence base, which is terribly important,” said Dr. Nissen.
The rise and fall of CVOTs
Certainly, the heart failure world has seen important advances in recent years, including the first mineralocorticoid receptor antagonist, spironolactone, shown in the 1999 RALES trial to be life prolonging in patients with heart failure with reduced ejection fraction and a first in class angiotensin neprilysin inhibitor, sacubitril/valsartan. But it’s a fair guess that heart failure has never seen anything like the sodium-glucose cotransporter 2 (SGLT2) inhibitors.
Likely very few in the cardiology world had ever heard of SGLT2 inhibition 20 years ago, even though the idea of SGLT2 inhibition dates back more than 150 years, to when a French chemist isolated a substance known as phlorizin from the bark of the apple tree and subsequent investigations found that ingestion of it caused glucosuria. The SGLT2 story is one of great serendipity and one in which Dr. Nissen played a prominent role. It also hints to something that has both come and gone in the last 20 years: the FDA-mandated cardiovascular outcome trial (CVOT).
It was Dr. Nissen’s meta-analysis published in 2007 that started the ball rolling for what has been dubbed the CVOT or cardiovascular outcomes trials.
His analysis suggested increased cardiovascular risk associated with the thiazolidinedione rosiglitazone (Avandia), then a best-selling diabetes drug.
“At the time, Avandia was the top selling diabetes drug in the world, and our meta-analysis was terribly controversial,” said Dr. Nissen. In 2008, he gave a presentation to the FDA where he suggested they should require properly powered trials to rule out excess cardiovascular risk for any new diabetes drugs.
Others also recognized that the findings of his meta-analysis hinted to a failure of the approval process and the postapproval monitoring process, something which had been seen previously, with cardiac safety concerns emerging over other antihyperglycemic medications. The FDA was also responding to concerns that, given the high prevalence of cardiovascular disease in diabetes, approving a drug with cardiovascular risk could be disastrous.
In 2008 they mandated the CVOT, one of which, the EMPA-REG OUTCOME trial, showed that the SGLT2 inhibitor empagliflozin significantly reduced the risk of a composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke by 14% (P = .04), driven by a 38% relative risk reduction in cardiovascular death (P < .001).Treatment with empagliflozin was also associated with a 35% reduction in heart failure hospitalization and a 32% reduction in all-cause death in that trial.
Additional groundbreaking CVOTs of empagliflozin and other SGLT2 inhibitors went on to show significant cardiorenal benefits and risk reduction in patients across the spectrum of heart failure, including those with preserved ejection fraction and in those with kidney disease.
“I think it’s fair to say that, had the FDA not mandated CVOTs for all new diabetes drugs, then the SGLT2 inhibitors and the GLP-1 [glucagonlike peptide–1] receptor agonists would have been approved on the basis of trials involving a few thousand patients showing that they lowered blood sugar, and we might never have found out what we know now about their benefits in individuals with established cardiovascular disease, in heart failure, and their ability to help people lose weight,” said Dr. Nissen. “And, of course, Avandia is long gone, which is a good thing.”
Interestingly, the FDA no longer requires extensive cardiovascular testing for new glucose-lowering agents in the absence of specific safety signals, replacing the CVOT mandate with one requiring broader inclusion of patients with underlying CV disease, chronic kidney disease, and older patients in stage 3 clinical trials of new agents.
“The SGLT2 inhibitors are already hugely important and with the growing prevalence of diabetes, their role is just going to get bigger. And it looks like the same thing will happen with the GLP-1 receptor agonists and obesity. We don’t have the outcomes trials for semaglutide and tirzepatide yet in patients with obesity, but given every other trial of this class in patients with diabetes has shown cardiovascular benefit, assuming those trials do too, those drugs are going to be very important,” added Dr. Cannon.
“The truth is, everywhere you look in cardiology, there have been major advances,” Dr. Cannon said. “It’s a wonderful time to work in this field because we’re making important progress across the board and it doesn’t appear to be slowing down at all.”