A study to evaluate the bioavailability (BA) of a single oral dose of MDV3100 (enzalutamide) formulated as a solid spray dried tablet compared to oral liquid-filled capsules, and the safety and tolerability of oral formulations.

Subjects are admitted to the clinic from days 1 to 5, followed by outpatient assessments up to Day 50. They return to the clinic for an end of study visit (ESV) 7-10 days after the last pharmacokinetic (PK) sampling or after early withdrawal.

Inclusion Criteria:

• The subject has a body mass index (BMI) range of 18.5 - 29.9 kg/m2, inclusive. The subject weighs at least 50 kg (screening).
• Male subject and his female spouse/partner who is of childbearing potential must be using highly effective contraception consisting of two forms of birth control (one of which must be a barrier method) starting at screening and continue throughout the study period and for 3 months after final study drug administration.
• Male subject must not donate sperm starting at screening and throughout the study period and for at least 3 months after final study drug administration.

Exclusion Criteria:

• Known or suspected hypersensitivity to enzalutamide, or any components of the formulation used.
• Confirmed CYP2C8 poor metabolizer status based on genotyping analysis.
• Any history of seizure including a febrile seizure in childhood, loss of consciousness, transient ischemic attack, or any condition that may pre-dispose to seizure.
• The subject has/had febrile illness or symptomatic, viral, bacterial (including upper respiratory infection), or fungal (non-cutaneous) infection within 1 week prior to first clinic check in.
• Use of grapefruit or marmalade in the week prior to admission to the Clinical Unit, as reported by the subject.
• Any significant blood loss, donated one unit (450 mL) of blood or more, or received a transfusion of any blood or blood products within 60 days or donated plasma within 7 days prior to clinic admission on Day -1.