In vivo drug-drug interaction studies - A survey of all new molecular entities approved from 1987 to 1997

Ninety-eight new molecular entities applications approved between 1987 to 1 991 (period I) and 193 applications for new molecular entities between 1992 to 1997 (period II) were surveyed for drug-drug interaction studies. In pe riod I (used as a comparator), 32 applications contained drug-drug interact ion studies for a total of 117 studies. In period II, 106 applications repo rted drug-drug interaction studies, and the number of studies per new molec ular entity ranged from 0 to 15. Most studies (77%) were performed in healt hy subjects, with 44% using crossover designs, 7% using parallel designs, a nd the remaining using fixed sequence designs, The most common dosing schem e for new molecular entities/interacting drug was multiple dose (47%), wher eas single dose/multiple dose was used in 31% of studies, and single dose/s ingle dose was used in 18% of studies. Of the 540 drug-drug interaction stu dies submitted in period II, 80 (15%) resulted in clinically significant la beling statements, Submissions for new molecular entities to the Center for Drug Evaluation and Research divisions most likely to include drug-drug in teraction studies were neuropharmacology, cardiorenal, antiviral, and antii nfective drugs, Some drug classes such as oncology drug products and radioi maging products were least likely to include drug-drug interaction studies in their submissions. We conclude that the use of drug-drug interaction stu dies in the drug development process has increased between the two periods.