Objective. To investigate how drug trials are carried out and reported in Norway and to which extent they are published.
Material and methods. All drug trials notified in 1996 were included in the study. Data were obtained from the ordinary form of notification, correspondence with investigators, study end reports, and a questionnaire designed for this study. The data were entered into a database.
Results. A total of 208 drug trials were notified. Most trials were initiated by the pharmaceutical industry (85%) and international multicenter studies constituted a major part (73%). End of study reports were sent to the authorities, in accordance with regulations, for 48 (23%) of the trials. Of a total of 159 trials with information about carrying out of the trial, 39 (25%) were interrupted or not started. Of a total of 143 trials with information about publishing, 77 (54%) were not published. Trials with a positive conclusion (54%) were more likely to be published than trials with a negative conclusion (38%).
Interpretation. Reporting of drug trials is not satisfactory. Due to low frequency of reporting, the authorities do not obtain a comprehensive overview of the trials.The pharmaceutical industry initiates the majority of the trials. Clinical researchers in Norway increasingly participate in international multicenter trials. Many trials are not performed as planned and less than half are published.