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NEJM Studies Challenge the Efficacy of Vertebroplasty BY LAUREN UZDIENSKI, AUGUST 7, 2009

Two studies published this week in the New England Journal of Medicine cast doubts over the efficacy of vertebroplasty.

The first study, conducted in Australia, randomized 78 patients in a multicenter, double-blind, placebo-controlled trial in which participants with one or two painful osteoporotic vertebral fractures were assigned to vertebroplasty or a sham procedure. The authors found that "similar improvements were seen in both groups with respect to pain at night and at rest, physical functioning, quality of life, and perceived improvement." No significant advantage was found for vertebroplasty at any time point during follow-up.

The second study, conducted by the Mayo Clinic, found similar results. 131 patients with one to three painful osteoporotic vertebral fractures were randomized to undergo either vertebroplasty or a sham procedure. Improved disability and pain scores were noted immediately following both procedures, with the study authors noting a trend toward a higher rate of clinically meaningful improvement in pain (a 30% decrease from baseline) in the vertebroplasty group.

These results have been met with some surprise and disbelief among physicians treating VCF patients. The Wall Street Journal quoted Allan Brook, the director of interventional neuroradiology at Montefiore Medical Center in New York City, as saying, “We take a patient who’s been lying in bed in a hospital, bedridden, you do the procedure and they’re home the next day. That is not a placebo."

Some of the limitations of the analysis include a small sample size and crossover between the groups (that is, patients were able to guess they had a sham procedure and proceeded to have the vertebroplasty.) Additionally, the Wall Street Journal noted a type of enrollment bias in that the patients in the most pain, and therefore the most to gain from the procedure, may not have been willing to risk being randomized to the simulated procedure. Enrollment may also have been limited by physicians' concerns that the study was unethical, and the WSJ reported that some hospitals did not allow their doctors to participate.

In an editorial also published in the NEJM, James N. Weinstein (SPORT's principal investigator) described some of the possible adverse events associated with vertebroplasty, which, while rare, include soft-tissue damage and nerve-root pain and compression related specifically to the leakage of bone cement as well as pulmonary embolism, respiratory and cardiac failure and death. He also used the editorial as an opportunity to encourage collaborative decision-making between the physician and patient, stressing that patients prefer to be more informed and will make decisions based on the best available evidence, echoing a an opportunity for further study of vertebroplasty.

Among the companies that may be affected by this data, Orthovita CFO Nancy Broadbent told Reuters, "We don't expect our Cortoss business to be affected at all by this." The company recently launched Cortoss for use in vertebroplasty and closed down 25% yesterday afternoon, just a day after reporting a strong 2Q:09 and beating both top and bottom-line estimates.

Medtronic was also slightly down at the close. Their Kyphon business contributed $609 million to total spinal and biologics sales of $3.4 billion in fiscal year 2009, though it should be noted that kyphoplasty differs from vertebroplasty in several key aspects. Vertebroplasty involves the delivery of bone cement into a vertebral fracture; kyphoplasty first inserts a balloon to create space in the fractured vertebra, restoring its height and shape, before the balloon is removed and the bone cement is delivered to the resulting space. Both procedures are typically performed by interventional radiologists. Medtronic has not commented publicly on these results. Stryker and JNJ, who are among several companies developing VCF treatments, have also not commented.

While investors may be wary, it's unclear how these studies will affect procedure volumes or product penetration. The Wall Street Journal offered examples of other cases where study results questioned established treatments, including a 2002 study that found no benefit to arthroscopic knee surgery, which appears to have only a limited effect on practice habits. While we don't expect procedure volumes to change overnight, these studies may signal a different trend: level I evidence is somewhat rare in orthopedics, but similarly rigorous studies may become more common as payers and other stakeholders demand increasingly strong data and comparative effectiveness gains traction.

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