NO GO: The Food and Drug Administration won't OK Merck's new combo cholesterol drug without more data. Merck says new data on compound MK-0653C, expected later this year, may address FDA questions.

LIPITOR LURE?: The experimental drug combines Merck cholesterol pill Zetia with generic Lipitor, which had been the top-selling drug ever but got generic competition three months ago.

NEW AND IMPROVED: Merck already sells Vytorin, a cholesterol pill that combines Zetia with generic Zocor, a Merck drug similar to but not as strong as Lipitor. The new combo might work better than Vytorin.