The guideline identifies these as (i) studies of pharmacologic properties known or thought to be related to the desired clinical effects (biomarkers), (ii) short-term studies of the main clinical effect, and (iii) PD studies of other properties not related to the desired clinical effect. Because a quantitative relationship of these pharmacological effects to dose and/or plasma drug and metabolite concentrations is usually of interest, PD information is frequently collected in dose response studies or together with drug concentration information in PK studies (concentration-response or PK/PD studies). The guideline states that dose-finding, PD and/or PK-PD studies can be conducted in healthy subjects and/or patients, and can also be incorporated into the studies that evaluate safety and efficacy in a clinical indication. In some cases, the short-term PD, dose-finding, and/or PK-PD information found in pharmacodynamic studies conducted in patients will provide data that contribute to assessment of efficacy, either because they show an effect on an acceptable surrogate marker (e.g., blood pressure) or on a clinical benefit endpoint (e.g., pain relief). Thus the studies identified here are healthy subject PD and PK/PD studies plus patient PD and PK/PD studies.
The reader must note that the guideline clearly states that when these PD studies are part of the efficacy or safety demonstration, they are considered clinical efficacy and safety studies that should be included in Section 5. Similarly, studies whose primary objective is to establish efficacy or to accumulate safety should be included in Section 5.
Section 5 is beyond the scope of this chapter.
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