This morning, an announcement from Medtronic rocked one of the hottest markets in medtech: renal denervation, the device-based treatment for hypertension. Medtronic announced that the results from its SYMPLICITY HTN-3 trial failed to meet its primary efficacy endpoint, namely reduction in office blood pressure. SYMPLICITY HTN-3 had been seen as the pivotal trial for the field of renal denervation and was expected to lead to approval of the first renal denervation device in the US. This trial was the most rigorously screened renal denervation trial to date, and randomized resistant hypertension patients to either renal denervation with the Symplicity catheter or to a sham procedure. These preliminary results are a major blow to what was expected to be a growth driver for some of medtech's biggest companies.

In fact, Medtronic's announcement is strike two for renal denervation. Almost exactly one month ago, St. Jude Medical halted its US EnligHTN IV trial for the EnligHTN renal denervation system. The company highlighted difficulties in enrollment for their randomized trial due to the necessary recruitment of their sham procedure arm. Having a sham procedure arm as part of the trial would likely cause referring physician to recommend a procedure with the approved Symplicity device rather than enroll patients in a trial with the possibility of a sham procedure being performed. It now appears that St. Jude may have dodged a bullet by cancelling its trial.

Medtronic further announced that because of the results, enrollment has been suspended in ongoing trials, and that these results could result in a one-time impairment charge based on the value of its renal denervation assets, signaling that the company is preparing for the reality that renal denervation will not live up to its previous hype.

This is an undeniable setback for the field and once darling growth story. In fact, for the past two years renal denervation had been positively mentioned on MRG's top ten trends in the global medtech market. Unfortunately, it might make the list again this year but for the opposite reason.

However, we will have to wait for specifics on the study to understand how the trial failed to meet its primary efficacy endpoint. Previous criticism of renal denervation studies pointed out that those studies measured reductions in office blood pressure, as opposed to ambulatory blood pressure, and therefore may not be capturing true blood pressure reductions. However, the primary endpoint for the SYMPLICITY HTN-3 trial was still a drop in office blood pressure, while a drop in ambulatory blood pressure was a secondary endpoint.

Questions about the exact cause of the trial's failure and its implications still linger: did the results indicate that there was no drop in blood pressure at all, or did they show that both the sham procedure and renal denervation itself drop blood pressure equally?indicating that the placebo effect is stronger than anyone could have anticipated? Is this the beginning of the end for renal denervation, or does it provide an opportunity for other competitors in the space to catch up to the current leaders while the market is frozen? If renal denervation isn?t the solution for hypertension, it leaves the door open for other novel devices to combat this growing problem.