Biotech Values

[DewDiligence]

ABT vs BSX: Non-Inferiority Turns into Superiority

[At two years, ABT’s Xience bested BSX’s Taxus on virtually every major clinical metric that was examined. MACE at two years was 7.3% for Xience and 12.8% for Taxus, a highly statsig advantage for Xience. I think it’s reasonable to conclude that, in due course, Xience will become the largest-selling DES in all major markets. Xience is not yet approved by the FDA, but an advisory panel endorsed approval by a 9-1 vote in Nov07.]

http://www.reuters.com/article/marketsNews/idINN1331632020080513

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Abbott Xience tops rival Taxus at two years

Tue May 13, 2008 11:13am EDT
By Bill Berkrot

NEW YORK, May 13 (Reuters) - Patients who received Abbott Laboratories' (ABT) drug-eluting stent had significantly fewer heart attacks and other major adverse events after two years than patients receiving a top-selling Boston Scientific Corp (BSX) stent, according a data presented on Tuesday.

Abbott shares rose more than 3 percent and Boston Scientific shares were down 3 percent.

While Abbott's experimental Xience V stent achieved a goal of non-inferiority to Boston Scientific's Taxus stent after one year in the study, it was clearly superior at two years, the trial's lead researcher said.

"Between one and two years the safety and efficacy seemed to be spreading between the two stents, and while the differences were impressive at one year, they're even more impressive at two years," Dr. Gregg Stone, professor of medicine at Columbia University Medical Center, said in an interview.

After two years, patients who received Xience stents had 45 percent fewer major cardiac events -- defined as heart attacks, cardiac death and need for repeat procedures due to blood vessel reclogging -- than Taxus patients, according to data presented at a medical conference in Barcelona.

In the 1,002-patient study, sponsored by Abbott, 7.3 percent of Xience patients experienced a major cardiac event, compared with 12.8 percent of Taxus patients, researchers said.

Abbott expects Xience to be approved for sale in the United States during the current quarter. This continuing five-year study is likely to help it grab significant market share.

"The result reaffirmed the superiority of Xience," Wachovia analyst Larry Biegelsen said in a research note.

He said the data were more impressive than those seen in an earlier Xience study "and reinforces our view that Xience will ultimately become the workhorse stent of choice."

The lucrative market has been dominated by Taxus and Johnson & Johnson's (JNJ) Cypher. Medtronic Inc's (MDT) drug-coated Endeavor joined the fray this year after winning U.S. approval in February.

Abbott released one-year results from the study last year, but physicians and health regulators are extremely interested in longer-term data amid concerns about potentially deadly blood clots developing long after stents are implanted.

These concerns have led to reduced use of the drug-coated devices and to patients staying on the blood clot preventer Plavix for six months or longer after receiving a stent.

"I do think this will restore some confidence and I think that this will be very reassuring, that we now have a second-generation stent which almost cuts the overall adverse events rate from drug-eluting stents in half," Stone said.

The biggest difference between the one-year and two-year data was the higher number of heart attacks seen in Taxus patients, Stone said. At two years, 5.6 percent of Taxus patients had had a heart attack, compared with 3.2 percent of Xience patients.

Xience proved superior on other measures in the study as well.

At two years, there was a statistically significant 32 percent reduction in target vessel failure with Xience compared to Taxus (10.7 percent vs 15.4 percent) -- a clear improvement over non-inferiority at one year. Target vessel failure is a reclogging anywhere in the treated blood vessel, not just at the site of the stent.

Xience showed a 40 percent reduction in target lesion revascularizations -- the need for repeat procedures due to a reclogging of the stented area: 4.6 percent versus 7.5 percent for Taxus.

Over the course of the second year, the rate of stent thrombosis, or development of blood clots, was low for both -- 0.3 percent for Xience and 1.0 percent for Taxus.

There was a strong trend toward fewer blood clots developing in Xience patients who discontinued Plavix after six months: 0.4 percent compared to 2.6 percent with Taxus. That did not reach statistical significance and so cannot be chalked up as a proven benefit.

"But its a six-fold difference, which if confirmed with longer-term follow-up or larger studies, which we're doing, it's potentially a very important difference," Stone said. "It's hard to ignore 2.6 percent versus 0.4 percent."
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