Medical Device Daily Washington Editor

Makers of drug-eluting stents (DES) may think that their products could not have been under more pressure than they were in 2006, but a new article appearing in a Canadian medical journal has thrown another dose of gasoline on a fire that seems unlikely to die out soon.

All the evidence says that doctors and patients still like the DES over their bare-metal stent (BMS) predecessors, but payers may see the article as one more reason to push back against yet another high-cost intervention.

The paper, appearing in the Jan. 16 edition of the Canadian Medical Association Journal, offers a meta-analysis of 19 previous studies of the cost-effectiveness of DES as compared to BMS.

Of that number, 10 are said to have concluded DES, in terms of cost effectiveness, is superior to BMS; however, it said the other nine concluded BMS is as cost-effective as DES.

The article also attempts to cast doubt on what was the initial endpoint “selling point” for DES. The authors state that “the absolute reductions in the rate of repeat revascularization observed with drug-eluting stents may be over-estimated owing to protocol-driven angiographic follow-up” in randomized trials.

“Our systematic review suggests that cost-effectiveness analyses can lead to partisan conclusions,” the authors write, adding that their work gives “empirical evidence that lower study quality and direct industry sponsorship were associated with positive conclusions.”

Still, the article acknowledges a key dilemma facing doctors, pointing out that “the clinical benefits of fewer repeat vascularizations . . . even if ephemeral, are enticing.”

The analysis included any study published between Jan. 1, 2001, and July 31, 2006, that fulfilled three conditions: The first of these was that it was “written from a third-party payer perspective,” while the second and third conditions were that the study included plain stents (BMS) as the comparator and provided original cost-effective data from “an unrestricted patient population.”

The measurement of interest for this analysis was a cost of $50,000 per quality-adjusted life year (QALY), but only nine of the 19 studies reported QALY data. Of those, seven reported a cost of more than $50,000/QALY.

The authors note that they opted not to distinguish between the two currently available types of coated stents because while sirolimus “appears to be more effective” than paclitaxel as a stent coating, “both are extensively used in clinical practices and because the prices of drug-eluting stents are comparable.” Sirolimus is the drug used on the Cypher, manufactured by Cordis (Miami Lakes, Florida), while paclitaxel is the drug on the Taxus, made by Boston Scientific (Natick, Massachusetts).

The analysis also assigned a metric to study quality, which was based on “a structured data-collection form created on the basis of previous published guidelines and recommendations.” The quality parameters “were extracted and assessed independently” by two of the four authors while all four dealt with any discrepancies.

However, the article states that this scoring scheme “does not provide information on the validity and appropriateness of the data used in the analysis,” although the team attempted to account for this by performing “a sensitivity analysis using the previously validated Quality of Health Economic Studies instrument.” This method is said to measure the quality of the input variables used by each study in the analysis, but is “also potentially more sensitive to subjectivity.”

The paper also acknowledges that the analysis is limited by the fact that “there is no definitive method on how to evaluate the quality of cost-effectiveness analyses” and that they were “unable to completely assess the validity of the input variables for each study.”

The authors insist that earlier studies, especially those financed by manufacturers, were less extensive than later studies sponsored by government agencies and that the later studies “argued that widespread use of drug-eluting stents was economically unattractive and that a more focused approach, concentrating on high-risk patients, is indicated.” But the article also points out that U.S. studies fairly consistently showed a more favorable picture for DES, which may, in turn, be due to “the high revascularization costs in the U.S. healthcare system.”

Scott Papillon, a media relations manager for Medtronic (Minneapolis), told Medical Device Daily that DES “have been proven in numerous clinical trials to be highly beneficial for certain patients, and physicians are in the best position to make decisions on what medical therapy is best for their patients.”

He noted also an article in the Oct. 17, 2006 edition of Circulation indicating that “the actual incremental cost for DES is just $691 based on this formula, with an incremental cost-effectiveness of $5,422 per repeat revascularization avoided.” Papillon said that any procedure amount less than $10,000 is generally seen indicating a good investment.

Paul Donovan, senior VP of corporate communications at Boston Scientific, said in an e-mail to MDD that the company is “pleased that the authors found a majority of the cost-effectiveness studies analyzed favor the widespread use of drug-eluting stents. Our TAXUS drug-eluting stent is a safe and effective therapy that has dramatically reduced the need for repeat procedures and improved the quality of life for millions of patients.”

Mariela Melendez, the director of communications at Cordis, told MDD that the company agrees with “the authors’ call for vigilance in interpreting study findings,” but made the case that “the review does not take into account the complexity of cost-effectiveness modeling. In such an analysis, careful attention must be paid to variables, such as country and time, as they can significantly affect outcomes.”