PF-00572778, a CRH antagonist, is expected to attenuate adrenocorticotropin (ACTH) and
cortisol responses to naloxone by blocking the effect of the CRH increases induced by
naloxone at the postsynaptic receptors. Demonstration of a statistically significant
attenuation of naloxone induced increases in cortisol and/or ACTH concentrations by
PF-00572778 compared to placebo would thus constitute proof of mechanism for the compound.
Therefore, this study is to evaluate pharmacodynamic effects of PF-00572778 following
naloxone challenge in healthy subjects.
Healthy male and/or female subjects between the ages of 18 and 45 years; Body Mass Index
(BMI) of approximately 18 to 30 kg/m2; and a total body weight >50 kg (110 lbs).
Evidence or history of clinically significant hematological, renal, endocrine, pulmonary,
gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease;
Family (1st degree relatives) and personal history of meeting Diagnostic and Statistical
Manual -IV (DSM-IV) criteria for alcohol abuse or dependence.