Where has renal denervation gone?
Renal denervation was the single hottest topic in cardiovascular medtech for two years, the star prospect of an industry hungry for growth stories. That, however, was before negative results of the pivotal SYMPLICITY HTN-3 trial were announced in January 2014 and subsequently presented at the ACC conference in March. Since the ACC conference, renal denervation has been relegated to the bench in terms of both clinical and market discussion and investigation. This isn?t due to lack of physician interest, but rather because industry has taken a step back and is proceeding with extreme caution (a huge about-face from the early days of rampant enthusiasm).
In fact, at a session at the recent TCT conference attended by several DRG analysts, Dr. Martin Leon was vocal in encouraging the medical device industry to continue investigation into renal denervation. Dr. Leon specifically noted that the information being discussed at TCT was a rehash of old data, rather than a discussion of new ideas and clinical trials, and that it is partially the responsibility of the medical device industry to initiate these trials.
Key opinion leaders that I spoke to when investigating this space have hinted that some companies are close to re-launching clinical programs. But what would it take to actually reinvigorate interest in this space? First of all, the obvious: evidence of efficacy must be generated. Strong evidence. This means designing clinical trials that will hold up to scrutiny of regulators, payors, and referring physician groups. To do this, the trials must be designed to eliminate several biases, including ?big day bias?, ?check once more bias?, and other confounding factors including the hawthorne and placebo effects. The way to do this is by designing trials that focus on ambulatory blood pressure monitoring and double blinding, so that the treatment effect can be isolated from certain patient and/or physician behaviors that tend to inflate results.
The second major thing that is necessary for a bounce-back is the development of a method to assess the completeness of denervation. An interesting subgroup analysis, presented by Dr. David Kandzari at EuroPCR, showed the number of burns directly correlated to the magnitude of the blood pressure drop in HTN-3.
At DRG, we just released our very first forecast for the hypertension management device market, which includes a heavy emphasis on renal denervation devices. Despite its uncertain future, this market is an exciting space to be following?one whose coverage demands a delicate balance between optimism and skepticism.