One of the most risky issues facing Merck (NYSE:MRK) just got pushed back for more than a year. The pharma giant announced that the Data Safety Monitoring Board for its Improve-It trial took an interim peek at the data and recommending continuing the trial.

The Improve-It trial pits cholesterol lowering drug Vytorin -- a combination of Zocor and Zetia -- against Zocor alone, which is available as a generic. Back in 2008, Vytorin failed to decrease the amount of plaque in patients' arteries compared to Zocor. But the Improve-It trial is an outcomes study -- measuring heart attacks, strokes, and other heart issues -- which is more definitive than measuring plaque in arteries.

Shares are up around 3% today. That isn't so much because continuing the trial means it's more likely that the trial will come out positive. Instead I think investors are breathing a sigh of relief because Vytorin isn't worse than Zocor. If it was, the committee would have ended the trial.

Of course, continuing the trial also means that Vytorin isn't decreasing heart attacks and strokes by a wide margin over Zocor. If it was, the committee would have stopped the trial because it isn't ethical to continue giving just Zocor to patients if we know it's inferior.

So the most likely outcome when the trial finishes in September 2014 is something in the middle. Either Vytorin improves outcomes a little. Or it doesn't really do anything, but doesn't hurt patients, either. That's what happened with Merck's Cordaptive. The drug looked great on paper (laboratory tests), lowering bad cholesterol and increasing the good kind, but when added to a statin like Zocor, Cordaptive didn't lower the occurrence of heart complications than a statin alone.

It makes you wonder how many more times the FDA will approve cholesterol drugs based on laboratory tests. Amarin (NASDAQ:AMRN) recently submitted Vascepa using laboratory tests as a surrogate endpoint. The FDA made the biotech wait until its outcomes study was "substantially enrolled" before it could apply, so the agency clearly doesn't want to wait too long to see the outcomes data.

If it hasn't already decided to require a pre-approval outcomes study for drugs in the works, you have to think that Improve-It failing to improve outcomes would push the agency over the edge. A multi-year trial would substantially delay companies developing drugs next-generation cholesterol drugs targeting PCSK9: Sanofi (NYSE:SNY) and Regeneron Pharmaceuticals' (NASDAQ:REGN) REGN727 and Amgen's (NASDAQ:AMGN) AMG 145 are in the lead. In addition to the delay and the added cost, it also makes them more risky because there are clearly no guarantees that positive laboratory tests will translate into better outcomes.

Fool contributor Brian Orelli has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. 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. The Motley Fool has a disclosure policy.