New research boosts hope that a highly anticipated, experimental class of cholesterol drugs can greatly lower the risk for heart attacks, death and other heart-related problems.

Studies presented Sunday at a cardiology conference in San Diego suggest that people taking one of these drugs had half the risk of dying or suffering a heart problem compared to others who were given the usual care, typically a such as Lipitor or Zocor.

Side effects remain a question, though, especially whether the drugs can harm thinking and memory.

One of the drugs is being developed by Amgen Inc. and the other by Regeneron Pharmaceuticals and Sanofi. The Food and Drug Administration will decide this summer whether to allow them on the market.