Objective: To investigate how drug trials are carried out and reported in Norway and to what extent they are published.
Material and methods: All drug trials notified in 1996 were included in the study. Data were obtained from the standard notification form, correspondence with investigators, end-of-study reports, and a questionnaire designed for this study.
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%). Mandatory end-of-study reports were submitted to the health authorities on 48 (23%) of the trials. Out of a total of 159 trials for which we have data, 39 (25%) were interrupted or not started. Out of a total of 143 trials for which we have data on publishing, 77 (54%) were not published. Trials with a positive conclusion (54%) were more likely to be published than those with a negative conclusion (38%).
Interpretation: The reporting of drug trials is not satisfactory. Because of low reporting frequency, health authorities do not obtain a comprehensive overview. The pharmaceutical industry initiates the majority of the trials and clinical researchers in Norway increasingly participate in international multicentre trials. Many trials are not carried out as planned; less than half are published.