Medical Device Daily Washington Editor
FDA has published a guidance for clinical trials for ablation therapies for atrial fibrillation (AF) and as always, the agency indicates that it is not utterly wedded to the idea of a randomized, controlled trial. However, firms in the business of making ablation catheters for percutaneous use need not bother to read this document because the document applies only to devices intended to be used under "direct visualization," a description that includes devices deployed via thoracoscopy. The agency issued a guidance for percutaneously delivered ablation catheters in 2004. FDA also states that part of the rationale for the guidance is that there is a need to distinguish between long-standing persistent AF vs. symptomatic paroxysmal AF, and the agency adds that the guidance deals with AF "as a rhythm disturbance" rather than AF "as a disease."
In the case of a trial that uses concurrent controls found outside the study, FDA says that a sponsor can enhance the control data with the use of covariate analysis or propensity score analysis to weed out any factors that might induce bias. As for studies using historical controls, the guidance indicates a preference for those with patient-level data. Failing that, historical controls might still be useful when employed to back up a performance goal the parameters of which are solidly backed by the literature.
The trial, FDA says, should include a measure of procedural effectiveness, but the agency notes that it is not persuaded of the legitimacy of acute effectiveness endpoints as surrogates for primary endpoints that are to be assessed at six months "or longer," at least where persistent forms of AF are concerned. For patients with longstanding persistent AF, the agency recommends a primary efficacy endpoint of freedom from AF for six months, and freedom of AF for nine months in the case of a trial for persistent AF. The rationale for this difference, the agency says, is that freedom from longstanding persistent AF is more easily assessed "given its predominantly continuous nature."
The primary safety endpoint, FDA suggests, would be a composite endpoint consisting of four elements including all-cause death and transient ischemic attack. Also on the list is myocardial infarction. Total follow-up should run to a year in order to assess the risk of several adverse events, including pulmonary vein stenosis unless the sponsor can make a solid argument as to why its device does not pose such a risk. The primary endpoints for a trial dealing with paroxysmal AF should be evaluated to at least a year, the guidance states, adding that this set of patients should perhaps be equipped with Holter monitors or other continuous monitoring equipment.
Other elements of the guidance address issues such as the patient population, the use of anti-arrhythmic drugs and anticoagulation. The document indicates that the agency will take into consideration any comments received up to Dec. 14 for the purpose of the final version of the guidance.
CMS proposes to cover HIV screens
The Centers for Medicare & Medicaid Services has proposed to reimburse for screening for the human immunodeficiency virus for a select group of individuals the agency deems to be at risk for the virus.
CMS opened the decision memo earlier this year (Medical Device Daily, March 16, 2009), partly at the behest of Congress, which made its wishes known via the Medicare Improvements for Patients and Providers Act of 2008. The CMS memo proposes to cover HIV screening "with an FDA-approved enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA) or rapid HIV antibody test" for a group of beneficiaries that includes men who have had sex with other men after 1975 and men and women who have had unprotected sex with more than one partner.
Also on the list of those whom Medicare may pay to screen are those who had a blood transfusion between 1978 and 1985, as well as those who have used illicit drugs via injection. As for forecasts of just how many Baby Boomers will be covered by this list, the real trick is to guess accurately how many of those born between 1946 and 1964 have had unprotected sex with more than one partner. Makers of HIV diagnostic kits no doubt could make a lot of money if that cohort is a large slice of the Baby Boomer pie of 79 million, which coined the phrase "love the one you're with." Of course, offering oneself up for the test is an admission that one behaved badly at one point in their lives, and most sociologists will testify that many people who respond anonymously for surveys will lie about things that generate cognitive dissonance. Hence, such behavior by Boomers is highly likely to be under-reported.
Bottom line for the savvy investor? Watch where the epidemiologists at CDC put their money.
CMS to cover 510(k) embolic protection
Governments are known for churning out paper, and the proposed decision memo issued last week by CMS regarding coverage of carotid artery angioplasty and stenting for stenosis reminds once again that the size of a pdf document is not necessarily related to the amount of meaningful content in a straight-line fashion. That is, unless, you happen to make an embolic protection device cleared by FDA.
CMS's Sept. 10 proposed decision memo states at the outset that the change consists of "a slight revision to the language regarding embolic protection devices." Doctors and patients most likely will not see much of a difference because CMS will now reimburse for cleared embolic protection devices rather than just approved devices when used in association with the procedure in patients with symptomatic carotid artery stenosis of 70%. Medical Device Daily opted to save a few trees and did not print out the entire 27-page document.
Mark McCarty, 703-268-5690;