By Peter Loftus
Of DOW JONES NEWSWIRES
A new study by health insurer UnitedHealth Group Inc. (UNH) concludes Merck & Co.'s (MRK) cholesterol drug Vytorin didn't significantly reduce the risk of heart attacks or strokes compared with a generic alternative or Pfizer Inc.'s (PFE) Lipitor.
Although the UnitedHealth analysis doesn't have the cachet of a clinical trial, it could underscore the uncertainty surrounding the worth of Merck's cholesterol-drug franchise. Questions resurfaced earlier this week when a clinical trial showed Abbott Laboratories' (ABT) Niaspan was superior to Merck's Zetia at clearing clogged arteries.
UnitedHealth's Prescription Solutions unit, which administers pharmacy-benefit plans for employers and insurers, performed the new study by analyzing administrative claims from a health-insurance plan that included commercial and Medicare clients.
The study tracked rates of hospitalization for heart attacks and strokes among a total of nearly 30,000 people with history of cardiovascular disease, who used Vytorin, simvastatin or Lipitor. Simvastatin is one-half of the combination pill Vytorin; the other half is Zetia. The study identified the patients between 2004 and 2006, and in some cases followed them up until March 2007.
The UnitedHealth study found there were 0.89 hospitalizations per 100 people per year among Vytorin users, 0.93 for Lipitor and 1.05 for simvastatin alone. But the differences between the groups weren't statistically significant, and so they could have been due to chance.
"Treatment with the combination Vytorin drug really showed no significant difference in those clinical results when compared with what we tried to match up as equipotent doses of simvastatin and [Lipitor] alone," said Brian Solow, senior medical director at Prescription Solutions.
The results are set to be presented Wednesday at the annual scientific sessions of the American Heart Association in Orlando, Fla.
Still, the study had limitations, including that patients weren't randomized to receive the various treatments as in a clinical trial. Also, a longer duration of follow-up would be needed to see if any statistically significant differences in outcomes emerged over time.
The study's sponsor also should be considered, too. As a pharmacy-benefit manager, UnitedHealth's Prescription Solutions unit has a financial interest in encouraging the use of cheaper generics over pricier brand-name drugs. The company's preferred list of cholesterol treatments steers members toward simvastatin, which is a generic drug, while Vytorin generally carries higher co-pays.
Merck has promoted Zetia and Vytorin for their ability to deliver substantial reductions in levels of bad cholesterol. But there's still no definitive proof that such potency translates into reduced risk for heart attacks and strokes beyond what can be achieved by drugs known as statins. Studies released last year raised questions about the drugs' efficacy and safety, which have caused sales to decline, though Merck has defended the drugs.
Merck spokesman Ron Rogers said the new UnitedHealth analysis should be interpreted "carefully" because it wasn't a randomized, controlled clinical trial. He said Merck believes the best evidence of whether Vytorin--or adding Zetia to a statin--can reduce the risk of heart attack or stroke versus a statin alone will come from a clinical trial titled "Improve-It," which is due to be completed around 2012.
-By Peter Loftus, Dow Jones Newswires; 215-656-8289; peter.loftus@dowjones.com