Two major players looking to establish the use of renal denervation therapy to treat high blood pressure put forward data this week showing their approaches could make a dent.
Designed to disrupt overactive nerve signals from the blood vessels surrounding the kidneys, ReCor Medical’s Paradise system cleared a randomized, sham-controlled study showing it could cut daytime blood pressure readings within the two months after the procedure.
The results help set up ReCor and its corporate owner, Otsuka Medical Devices, to compete with Medtronic—which presented long-term data from its Symplicity system, demonstrating significant blood pressure reductions out to three years. Both companies unveiled their findings at the Cardiovascular Research Foundation’s annual Transcatheter Cardiovascular Therapeutics (TCT) conference in Boston.
ReCor’s study of its ultrasound-powered Paradise device randomized 224 participants with uncontrolled hypertension, who were told to stay off their related medications for at least two months at the start of the trial, unless their blood pressure reached certain criteria.
Those who had the Paradise procedure saw daytime ambulatory systolic blood pressure readings drop by nearly 8 mmHg on average, compared to nearly 2 mmHg in the control arm, meeting the study’s primary endpoint. The company said similar reductions were seen in nighttime and 24-hour measures as well as readings taken at home and in the doctor’s office.
The results were also consistent with multiyear findings from the company’s previous trials of patients who were taking no medication and those taking a triple anti-hypertensive combination regimen, according to a statement from the study’s principal investigator, Michel Azizi, M.D., Ph.D., a professor of medicine at the European Hospital Georges Pompidou in Paris.
However, last year, Paradise failed to meet its target in a clinical trial conducted in Japan and Korea, shortly after ReCor began the system’s European commercial launch. The company attributed that particular miss to the inadequately controlled usage of antihypertensive drugs among the study’s participants, which muddied the device’s measurable effects.
Paradise uses ultrasonic energy to generate heat while circulating cooling water in the catheter’s balloon to control its temperature, helping burn out the nerves surrounding the arteries of the kidney which can send signals urging the brain to raise the body’s blood pressure.
Medtronic’s Symplicity device, on the other hand—as well as its upgraded version, the Symplicity Spyral—uses targeted radiofrequency energy to generate heat from a series of catheter-based electrodes.
The medtech giant presented three-year data from a trial of its first-generation device—dubbed SYMPLICITY HTN-3—which had seen clinical setbacks of its own. In 2014, at the same study’s six-month mark, Symplicity did not pass its primary or secondary efficacy endpoints, though it met its primary safety goal.
The latest analysis presented at the TCT conference, alongside publication in The Lancet, included 101 patients from the sham control arm that crossed over to the other side of the study and underwent the full renal denervation procedure after the six-month analysis.
Three years after their procedure, patients with treatment-resistant hypertension logged a 26-mmHg reduction in systolic blood pressure readings taken in a doctor’s office, compared to a nearly 6-mmHg reduction among the sham group. The study also posted a more than 15-mmHg reduction in 24-hour ambulatory systolic blood pressure, versus a 0.3-mmHg gain in the control arm.
"While we did not find a significant six-month blood pressure reduction difference in [renal denervation] versus sham in HTN-3, we felt that there was much to learn by following HTN-3 patients for a longer time period, particularly in those sham patients with sustained blood pressure elevations who 'crossed over' to RDN,” said Jeffrey Popma, M.D., chief medical officer of Medtronic’s coronary and renal denervation and structural heart and aortic divisions.
In the interim, the company debuted the Symplicity Spyral, with a helical design and four independent, spaced-out electrodes for more even ablation. The upgraded device demonstrated in 2020 that it could help lower blood pressure readings after three months in patients not taking anti-hypertensive drugs.
That version also delivered three-year study results this past April at the annual meeting of the American College of Cardiology, with 83.3% of treated patients reporting systolic blood pressure of under 140 mmHg, compared to 43.8% in the sham control group, after average baseline measurements of above 150 mmHg.
Medtronic said it also plans to present data from an extended study of the Spyral device focusing on patients already on blood pressure regimens during November’s American Heart Association Scientific Sessions in Chicago.