The annual meeting of the Heart Rhythm Society got under way in earnest today in Boston with a quintet of late-breaking clinical results from studies that sought creative ways to answer some of cardiology’s most pressing problems.
“Most of these studies have not been the conventional head-to-head clinical trials with the usual bopring study structure. What we’ve seen today are some really innovative, really rigorous, quite novel, innovative ways of approaching studies,” noted Dr. Robert Sheldon, of the University of Calgary, in presenting data from his own trial comparing pacemakers and implantable cardiac monitors.
Long-awaited data released today from a large clinical trial comparing catheter ablation with drug therapy in treating atrial fibrillation showed no significant benefit for ablation, according to Dr. Douglas Packer, who presented the findings today at the annual meeting of the Heart Rhythm Society in Boston.
The 2,204-patient trial, sponsored by the National Institutes of Health and industry players Medtronic (NYSE:MDT), Boston Scientific (NYSE:BSX), Abbott (NYSE:ABT) and Johnson & Johnson (NYSE:JNJ) unit BioSense Webster, focused on a primary composite endpoint of total mortality, disabling stroke, bleeding and cardiac arrest. When considering all patients as randomized, Packer said, the researchers saw no difference between the control and treatment arms.
Researchers included patients who “warranted therapy” due to their under-treated paroxysmal or persistent atrial fibrillation and followed them, on average, for 48 months. The patients were randomized 1:1 to either ablation or medical therapy with rate or rhythm control drugs.
“I would like to thank the Fix HF C5 study investigators and the Impulse Dynamics’ team for completing this important study with its very encouraging results,” CEO Dr. Simos Kedikoglou said in prepared remarks. “We anticipate submission of the final PMA module to the U.S. FDA in June 2018.”
“The study reinforced ablation as a preferred therapy option for treating patients with symptomatic atrial fibrillation (AF) while showing a distinct reduction in mortality for patients receiving ablation therapy. The results are encouraging and should help more patients with AF be evaluated for ablation as a front-line therapy option,” noted Dr. Srijoy Mahapatra, medical director for electrophysiology at Abbott.
Packer pointed out that there were concerns in the sub-group analyses, mainly that a number of patients crossed over between the treatment and control arms. Many patients who were randomized to ablation did not actually receive ablation therapy, due to patient preference or cost, he noted.
That said, for those that received ablation therapy, there was a benefit in relative risk reduction, Packer said.
“You can’t get a benefit from the therapy if you don’t get the therapy,” he explained.
There was a 47% drop in the relative risk of recurrent atrial fibrillation for patients who received ablation compared to those who received drug therapy, he said.
The takeaway, according to Packer, is that ablation may be right for patients in particular sub-groups – like those who are under the age of 65 or have a history of heart failure – but it would be wrong to assume that all atrial fibrillation patients should be ablated based on the data from Cabana.
“That’s simply not the case,” he said. “We do think that ablation is an acceptable treatment strategy for treating atrial fibrillation with low adverse events rates, which surprised us quite a bit, in higher-risk patients.”
“I think the bulk of data now presented suggest at the very least [ablation] is equivalent, and in many cases probably superior to drug therapy. I think patients should be allowed to have it as first-line treatment by people who know what they’re doing,” Dr. Eric Prystowsky said at HRS, commenting on the study.
“I would recommend for everyone here to avoid the usual ‘trial creep’ and that means you have to read the paper when it comes to look carefully at who was in the trial,” he added, pointing out that the results are largely dependent on patient sub-groups.
Parker also said that they will soon publish analyses relating to quality of life measures in patients who were ablated.
“Sometimes there are patients who are so burdened by their atrial fibrillation that they don’t care about mortality. They care about quality of life,” he said.
“Clinical trials give you data and they give you knowledge, but they don’t give you wisdom or judgement,” added Dr. Robert Sheldon, of the University of Calgary. “I think that Cabana should increase your thinking and change your thinking, but what it does for each particular patient depends upon the patient.”
Asked whether the Cabana results will affect how she advises patients, Dr. Christine Albert of Boston’s Brigham and Women’s Hospital said she wants to review the data in detail.
“I want to see the paper,” Albert said.