Rox Medical said it closed enrollment in a 100-patient clinical trial of its Rox Coupler device, designed to treat hypertension by connecting the femoral artery and the femoral vein.

CEO Rodney Brenneman told MassDevice.com that Rox Medical, a Stanford spinout established in 2004 to pursue several indications including chronic obstructive lung disease and heart failure, noticed a dramatic effect on high blood pressure in COPD patients implanted with the device.

That inspired a small, 8-patient feasibility study to examine the device in hypertensive patients without COPD that delivered "compelling’ results, Brenneman told us.

After the painless, hour-long procedure, "we can hook a pressure transducer up to the arterial line and immediately see a blood pressure drop," he said.

“It’s very repeatable and you know, on the table in the cath lab, that you just achieved the blood pressure drop," he said. "By the time they leave the hospital, the next day – typically in Europe they keep them over 1 night – we’ll measure their blood pressure and they’re already showing a drop, so you basically send someone out the door with an improvement."

Despite the high-profile failure of Medtronic‘s (NYSE:MDT) Symplicity 3 trial, Brenneman said he’s confident there’s a place for an interventional approach to high blood pressure – especially for patients who, for 1 reason or another, can’t control their high blood pressure with drugs.

"Ultimately all the fundamentals are still there, all the things that are interesting about interventional treatments are still there – you still have massive amounts of patients that are unaddressed by poly-pharmacy. I fully expect that renal denervation will be shown to be beneficial for 50% to 70% of patients who get treated; I think it will have a place. At the same time, there’s an issue of time-to-therapy, and the fact that Rox can offer a severe patient an immediate drop in blood pressure is, I think, going to be an extremely compelling story," he said. "The fact that we can be used alongside of any renal denervation therapy and show benefits becomes, I think, very interesting and compelling to everyone with a denervation franchise who might want to add to it. And we’re going to be extremely interesting to those who haven’t entered the market yet, because they don’t have an ablation technology or don’t have a play there. Rox could be extremely interesting to them. We represent a pathway into the U.S. market that arguably many others don’t have without some battle in front of them on the patent front."

Results from the pivotal trial are slated to be released this fall, according to a press release. Brenneman told us that the picture after that, assuming a positive outcome, is likely to involve more trials and limited European commercialization.

"We are preparing a submission for a U.S. trial this year," he said. "Our plan is basically to finish the follow-up on this trial – we should have 6-month data on almost all of these patients by the end of the 3rd quarter, so by late this year we should be presenting the results."

Rox has raised about $55 million in venture capital backing over the past 10 years, undergoing a re-tooling as the VC world consolidated and Rox decided to focus on the hypertension indication, Brenneman said. Initial backers included Versant Ventures, Prism VentureWorks, Domain Assoc. and Essex Woodlands, he told us.

"When we re-focused on hypertension, it was right in the middle of the consolidation of the venture world itself, and although there were a number of dynamics in play there we ended up with kind of a consolidation back to Versant and Domain, moving forward in the hypertension realms, and we shed the Essex Woodlands and Prism investors," he explained. "This has really streamlined the company and the board in a positive way."