Fixed Dose Study of PD 0332334 and Paroxetine for the Treatment of Generalized Anxiety Disorder

The study will consist of 3 phases: an initial screening phase which must be completed 7 to 14 days prior to randomization; an 8-week double-blind treatment phase; and a 2-week double-blind dose-tapering follow-up phase. After obtaining written informed consent the investigator will initiate washout of prior psychotropic medications. After the washout of prior psychotropic medications has been completed the investigator must ensure that the subject is no longer taking psychotropic medication for at least 14 days prior to the randomization visit. In addition the investigator must ensure that screening visit procedures (with the exception of obtaining informed consent) are completed within 14 days of the randomization visit. Potential subjects will be approached during a regularly scheduled clinic visit, upon referral from another physician, or in response to research advertisements. Those who call in will participate in a short phone pre-screen. This allows us to determine if the person fits the most limiting inclusion/exclusion criteria before requesting they dedicate a longer period of time for an in-person screen. Additionally it gives interested individuals the opportunity to learn more about the study and to review the consent form with family, friends, and other physicians prior to coming in for the screen and making a final decision regarding study enrollment. Once the subject has given informed consent, the screening process for the study will commence. Subjects who fulfill entry criteria will be randomized to receive ONE of the following 4 treatments in a double-blind fashion: PD 0332334 225 mg twice a day, PD 0332334 300 mg twice a day, placebo, and paroxetine 20 mg once in the morning. PD 0332334 will be titrated up in the PD 0332334 225 mg twice a day and PD 0332334 300 mg twice daily treatment groups. The titration of PD 0332334 will be from 125 mg in the beginning of the study. In addition the PD 0332334 225 mg twice a day and PD 0332334 300 mg twice a day treatment groups will be titrated down at the end of the study. The 20 mg daily dose of paroxetine used in this study is based on the approved label for the use of paroxetine in patients with generalized anxiety disorder. Doses were selected for this Phase 3 study based on safety and efficacy information known about PD 0332334 and pregabalin, an α2δ ligand approved for the treatment of generalized anxiety disorder in Europe The subjects enrolled will be men and women ages 18 to 65 who meet DSM-IV criteria for generalized anxiety disorder with a preponderance of anxious symptoms over depressive symptoms. De-identified blood samples will be collected from study subjects at Screening (Visit 1) according to the standard Molecular Profiling supplement to the protocol. Participation in this component is optional for study subjects. Samples may be utilized in the future to investigate generalized anxiety disorder genetics, expression metabonomics and protein biomarker profiles, drug-response, or other genetic or biomarker questions. \[Metabonomics: The study of metabolic responses to drugs, environmental changes and diseases. Metabonomics is an extension of genomics (concerned with DNA) and proteomics (concerned with proteins). \] Additionally, partners of male participants who become pregnant during the course of the study, will be requested to participate in order for the sponsor to collect safety information and understand the effects, if any, that PD 0332334 may have on her pregnancy or the fetus. Details of the this sub-study are described in the separate 'pregnant partner' consent form. Pregnant partners will be be asked to sign a separate HIPAA and consent form in order to participate. The investigators have recently received notification of an serious adverse event at another site that has already begun recruitment for this study. The MediWatch report for that serious adverse event is included as a Supporting document on WEBRIDGE. Additionally, a protocol change clarifying the procedures to collect lab information to calculate the estimate Creatinine Clearance has been submitted. This document has been added as a supporting document on WEBRIDGE (IRB web-based management portal).