Merck (NYSE: MRK) finally has outcome data proving that Vytorin does something other than just reduce cholesterol.

Unfortunately, it may be too little and too late to do anything about the sales cut that Vytorin has taken over the past few years.

Vytorin was approved based on its ability to lower cholesterol, but that's considered a surrogate endpoint. Doctors and patients don't care about the results of a lab test; whether the drug prevents heart attacks and strokes is what's important.

A few years ago, Merck and Schering-Plough, before Merck bought it, tried to show that Vytorin was helping patients by lowering the plaque in patient's arteries. Unfortunately, the clinical trial results showed that Zocor worked just as well as Vytorin, which is a combination of Zetia and Zocor, leading doctors to figure a statin such as Zocor or Bristol-Myers Squibb's (NYSE: BMY) Pravachol, both available as cheap generics, might be good enough. The stronger statins still under patent protection, Pfizer's (NYSE: PFE) Lipitor and AstraZeneca's (NYSE: AZN) Crestor, also seemed to benefit from the findings.

Fast-forward to yesterday, when researchers presented results from a trial testing Vytorin in patients with chronic kidney disease. Vytorin reduced the incidence of first major vascular events -- heart attacks, strokes, and the like -- by 16.1% compared with the placebo.

That's great; Vytorin is better than nothing. Merck will pick up some sales from the added indication.

But it doesn't really answer the question of whether Vytorin is better than statins at preventing heart attacks and strokes, because they weren't compared in this patient population.

A large outcomes trial testing Vytorin against Zocor in patients with high cholesterol is in progress but isn't scheduled to be completed until 2013. It could be the definitive proof doctors are looking for, but it'll come a little late.

Opposite ends of the political spectrum, but one conclusion on preventing financial calamity.

Pfizer is a Motley Fool Inside Value recommendation. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.