On 12 July, Medtronic announced that the US FDA has conditionally approved the protocol for SYMPLICITY HTN-3, the company’s US clinical trial of renal denervation with the Symplicity Catheter System for the treatment of resistant hypertension. Patient enrolment in the landmark study is expected to start soon.
Medtronic is leading the development of renal denervation therapy. Having received Europe’s CE mark and a listing with Australia’s Therapeutic Goods Administration (TGA), Medtronic’s Symplicity Catheter System is commercially available in Europe and Australia.
FDA approval of the SYMPLICITY HTN-3 protocol enables Medtronic to become the first company to conduct a randomised, controlled trial of renal denervation in the United States. The Symplicity Catheter System is not approved by the FDA for US commercial distribution.
The principal investigators of SYMPLICITY HTN-3 are George Bakris, professor of Medicine and director of the Hypertension Center at the University of Chicago Medical Center; and Deepak L Bhatt, associate professor of medicine at Harvard Medical School, chief of cardiology for the VA Boston Healthcare System and director of the Integrated Interventional Cardiovascular Program at Brigham and Women’s Hospital and the VA Boston Healthcare System.
“The imminent start of this clinical trial marks a pivotal point in the study of hypertension treatments,” said Bakris, who also serves as president of the American Society of Hypertension. “SYMPLICITY HTN-3 will assess the efficacy and safety of renal denervation with the Symplicity Catheter System— a treatment approach that represents a first in our field: a catheter-based intervention for patients with resistant hypertension who have been unable to achieve target blood pressure levels despite multiple medications.”
Bhatt added: “There is already a great deal of excitement about this trial in the medical community because of its potential to shed light on novel treatments for hypertension.”
SYMPLICITY HTN-3 is a single-blind, randomised, controlled trial designed to evaluate the safety and effectiveness of renal denervation with the Symplicity Catheter System in patients with resistant hypertension. Across 60 US medical centres, the study will enrol approximately 500 patients who will be randomised to receive either renal denervation and treatment with anti-hypertensive medications or treatment with anti-hypertensive medications alone. The primary endpoints of the study are the change in blood pressure from baseline to six months following randomisation and incidence of major adverse events one month following randomisation.
The Symplicity Catheter System accomplishes renal denervation, a minimally invasive procedure that modulates the output of the sympathetic nerves located outside the renal artery walls. The system consists of a proprietary generator and a flexible catheter. The catheter is introduced through the femoral artery in the upper thigh and is threaded up into the renal artery near each kidney. Once in place, the tip of the catheter delivers low-power radiofrequency energy according to a proprietary algorithm, or pattern, to modulate the surrounding sympathetic nerves. Renal denervation does not involve a permanent implant.
Clinical research to date shows that renal denervation with the Symplicity Catheter System may provide a significant and sustained reduction in blood pressure levels for many patients with uncontrolled blood pressure despite multiple medications. Results from SYMPLICITY HTN-2, a randomised, controlled trial of 106 patients in Europe, Australia and New Zealand, showed that patients with resistant hypertension randomised to renal denervation achieved a mean blood pressure reduction of 32/12mmHg at six months, whereas the patients in the control group randomised to anti-hypertensive medications alone had blood pressures that did not vary from baseline (1/0mm Hg). The overall occurrence of adverse events did not differ between groups.