Comparative trials in registration files of cardiovascular drugs: comparator drugs and dosing schemes.

Registration files of 13 cardiovascular drugs were analysed with respect to the number of double-blind phase-III clinical trials, the use of placebo and active comparator drugs and their dosing schemes. Half of the 146 double-blind trials used active comparator drugs. The majority of files included first-choice reference drugs, but we also found trials in three files with lower dosing schemes of comparator drugs and four files which included only placebo or active controlled double-blind trials. To allow a better interpretation of the information provided in European Public Assessment Reports, which are published for every product approved for marketing in the European Union, uniform reporting is recommended on basic details of trial design, such as comparator drugs used and dosing schemes.