The European Society of Hypertension (ESH) is calling for rigorous trials on renal denervation as a therapy for patients with treatment-resistant hypertension in the wake of results presented in the failed SYMPLICITY HTN-3 clinical trial.

SYMPLICITY HTN-3 was a prospective, single-blind, randomized sham-controlled trial, with patients receiving either renal denervation treatment with the Symplicity catheter or renal angiography as the sham control. The trial failed to meet its efficacy endpoint. Findings were presented March 29 at the American College of Cardiology scientific session in Washington D.C.

Renal denervation using the Symplicity device received CE mark in Europe and is not approved in the U.S. European approval was based on several trials that found sizable reductions in blood pressure in hypertensive patients treated with renal denervation, but those trials lacked elements such as a sham control and blinding that HTN-3 included.

“The European Society of Hypertension believes that although in the Symplicity HTN-3 study use of an appropriate control group makes the results less open to confounders than those of previous studies, the conclusion that renal denervation is ineffective is not justified,” ESH wrote in a note posted on its website.

The society pointed to subgroup data in HTN-3 that may signal benefits for specific populations. “[T]he reaction to the negative results of the Symplicity HTN-3 study should not be to abandon the renal denervation approach, but to perform further studies of high scientific caliber that could provide further evidence on its overall position in the treatment of resistant hypertension, determine whether the blood pressure effects are limited to some patients' subgroups (and clarify their characteristics), and see whether and to what extent their blood pressure reductions translate into cardiovascular and renal protection.”

ESH and the International Society of Hypertension will hold a joint meeting in Athens June 13-16 that will include studies on renal denervation and other topics.