An analyst raised doubts last week about Edwards Lifesciences' ability to gain approval for all studied indications in its closely watched U.S. trial for the Sapien percutaneous aortic valve.

JP Morgan's Michael Weinstein downgraded the company's stock from "neutral" to "underweight" Aug. 7 to reflect his doubts about the outcomes of the complex, multi-arm PARTNER trial. The stock fell 9% on the downgrade to close at $57.84.

Sapien has had a good start on the market since it launched in Europe late last year (¹ Also see "Edwards’ Sapien Sales Drive 24% Gain In Q2 Heart Valve Revenue" - Medtech Insight, 28 July, 2008., p. 8). And the firm has projected FDA approval by 2011. But Weinstein says that based on conversations with cardiologists and cardiothoracic surgeons, including some involved in the 1,040-patient PARTNER study, mortality rates have been higher than expected.

"The issue here is less with the procedure than it is with patient selection. Simply put, the patients who are receiving implants today are, more often than not, too old and too sick with too many comorbities," Weinstein writes. He says this is particularly the case in patients that are receiving the implant via the transapical approach, a procedure through the rib cage performed on patients with limited femoral artery access.

The trial includes patients who are candidates for more conventional open-heart surgery (where Sapien is compared to surgery) and those that aren't (where the comparison is to drug treatment alone). In December, Edwards added 500 patients to the trial protocol to account for increased mortality rate assumptions (² Also see "Edwards Redesigns PARTNER Trial, Pushes Back Sapien Approval Timeline" - Medtech Insight, 17 December, 2007., p. 10).

But Weinstein says that surgeons are still concerned that the patient risk profile could make it difficult to achieve statistical significance on mortality measures, particularly in the comparison to surgery. He doubts whether the transapical approach will make it to the U.S. market at all.

The firm said in a statement that Weinstein's points were addressed in December, and "we remain confident that the PARTNER trial will demonstrate significant patient benefit."

- Chloe Taft (c.taft@elsevier.com)

Analyst Bursts Edwards’ Bubble On PARTNER Percutaneous Valve Trial

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