Postmarketing Surveillance of Drug Efficacy Clinical observations and non-experimental research are important

Studies of drugs which have been marketed sometimes reveal adverse effects which were not discovered during animal and human premarketing testing. Postmarketing studies should also be used to further assess the efficacy of a new drug. 93 drugs, recently marketed for 131 uses or indications, were assessed to provide ' ... data on the frequency with which post-marketing evaluation of drug efficacy can be assessed by experimental or non-experimental means.'

In 89 (68%) uses, the absolute efficacy (relative to placebo) of the drug was obvious from clinical observations in an uncontrolled series of patients or in an individual patient and formal comparative research was unnecessary. The remaining 42 drug uses required formal research to assess their absolute efficacy. Of these, 6 (14%) studies could only be experimental (designed specifically to gain scientific information), 1 (2%) could only be non-experimental (observing the results of therapy given for reasons other than the gain of scientific information), and 6 (14%) studies could be either experimental or non-experimental. 29 uses could not be studied by either technique.

For the study of relative efficacy (relative to an alternative therapy), all 131 uses required formal research. 37 studies could only be experimental and the remaining 94 could be experimental or non-experimental.

Postmarketing research is necessary to provide additional information on drug efficacy. The analysis of this data shows that clinical observations (when formal research is not required) and non-experimental studies (when formal research is needed) can provide a large proportion of this information required on drug efficacy. Strom, B.L. et al.: American Journal of Medicine 77: 703 (Oct 1984)

0156-2703/84/1027-0003/0$01.00/0 © ADIS Press INPHARMA'"' 27 oct 1984 3