Postmarketing surveillance prospective studies

Other activities that fall within the area of postmarketing surveillance require input from, if not handling by, those responsible for clinical drug safety. These may include observational (non-interventional) studies, which may be retrospective or prospective, and other projects specifically designed to investigate a safety issue. 

Whereas Phase 1, 2, and 3 studies are conducted prospectively using subjects or patients whose entrance into the study depends on strict inclusion and exclusion criteria. Phase 4 studies employ mainly observational, rather than exclusionary, study designs. Postmarketing surveillance and any additional studies requested by the regulatory agency as conditional approval of the NDA are conducted during Phase 4. 

Adverse effects associated with famciclovir have been collected in over 6000 patients in two postmarketing surveillance studies (5). Only headache, abdominal symptoms, dizziness, vomiting, and diarrhea were associated with the drug. Two prospective trials have confirmed the low frequency of adverse effects, the more common ones being nausea, headache, vomiting, and diarrhea (6,7). 

Chiu P-Y, Dai D-E, Hsu H-P, Lee C, Lin J-J, Kuo H-C, Huang Y-C, Liu Y-C, Tsai C-P. Safety/tolerability and efficacy of rivastigmine in Taiwanese patients with Alzheimer s disease. A prospective postmarketing surveillance study. Clin Drug Invest 2009 29 729-38. 

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