Editors at the world's most prominent medical journals, alarmed that drug companies are exercising too much control over research results, have agreed to adopt a uniform policy that reserves the right to refuse to publish drug company-sponsored studies unless the researchers involved are guaranteed scientific independence. The journal editors decided to act after several recent cases involving charges that drug companies tried to withhold research results or present them in the most favorable way. "It's become a huge problem," said Frank Davidoff, editor of the Annals of Internal Medicine.