Five studies were released late today by The New England Journal of Medicine on its web site and find the devices cut the need for repeated procedures by half, and seem safe for healthier patients. The problem: there’s not much known about the way these work in 60 to 70 percent of the patients who are sick and receive stents “off-label,” or beyond the uses approved by the FDA.

The move comes after mounting concern the devices cause an unnecessarily high risk of blood clots, which prompted an FDA advisory meeting two months ago.

As The Wall Street Journal (subscription required) points out, rigorous trials of stents in sicker “off-label” patients are in the early stages, and published data isn’t expected for several years. The results may be, relatively speaking, good news for the manufacturers, including Johnson & Johnson and Boston Scientific. But experts say the worries aren’t over.

“Am I satisfied with the timeliness of the data? No, I’m not,” says William Maisel, who chaired the FDA panel and wrote an accompanying editorial, told the paper. “We still don’t have the answers to some of the important questions…I think there will be a continued reduction in the off-label use of drug-eluting stents.”

[tags]Boston Scientific, Drug-Coated Stents, FDA, Johnson & Johnson, New England Journal of Medicine[/tags]