There's no evidence Merck & Co.'s blockbuster cholesterol drug Vytorin causes cancer, federal regulators said Tuesday.

The Food and Drug Administration reviewed data based on a trial called SEAS that was based on Zetia, Vytorin and Merck's related drug. Findings from and ongoing studies were also considered. The data said Vytorin or Zetia increase the risk of cancer or cancer-related death, but an association was ruled out.

"We're pleased with the conclusions reached by the FDA," said Merck spokesman Ron Rogers.

In January 2008 a study called ENHANCE raised questions about the drugs' effectiveness. In July 2008 the SEAS trial found more cancer cases among Vytorin patients.

Leerink Swann analyst Seamus Fernandez said the FDA statement released on Tuesday was positive.

Fernandez said, "you're never going to really be able to state definitively that there isn't a cancer risk."

Vytorin combines Merck's statin Zocor, or simvastatin, with the newer Zetia. Zetia's generic name is ezetimibe.

The FDA however said it was not advising doctors or patients to stop using the medicines. Sources also said that analysis of cancer data from the two larger studies, SHARP and IMPROVE-IT stated that an increased risk of cancer was not established by Vytorin.

SHARP which is expected to conclude in 2010 and IMPROVE-IT in 2012 would show a better picture, researchers believed.