The GAO has issued a report, “New Drug Approval: FDA's Consideration of Evidence from Certain Clinical Trials,” examining FDA’s use of non-inferiority trial evidence as part of the drug approval process. According to the report, evidence from non-inferiority trials was included in 43 of the 175 new drug applications (NDAs) for new molecular entities submitted between FY 2002 and 2009, many of which were for antimicrobial drugs. As of December 31, 2009, FDA approved 18 of the 43 NDAs on the basis of evidence from non-inferiority trials (certain additional NDAs were approved based on other evidence). The GAO also examined the characteristics of these trials, and describes FDA’s guidance on these trials. According to GAO, “the agency has become more conservative in allowing evidence from non-inferiority trials to demonstrate a drug’s effectiveness,” both by limiting the indications for which these trials may be used and by becoming more rigorous in its review of evidence from non-inferiority trials.