Inclusion Criteria:

• Healthy male subjects between the ages of 18 and 55 years, inclusive (Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and pulse rate measurement, 12-lead ECG and clinical laboratory tests).
• Body Mass Index (BMI) of approximately 18 to 30 kg/m2; and a total body weight >50 kg (110 lbs). A BMI at the lower limit of 17.5 kg/m2 may be rounded up to 18.0 kg/m2; a BMI upper limit of 30.5 kg/m2 may be rounded down to 30.0 kg/m2 and will be acceptable for inclusion.
• An informed consent document signed and dated by the subject or a legally acceptable representative.
• Subjects who are willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at time of dosing) disease or clinical findings at Screening.
• History of febrile illness within 5 days prior to the first dose.
• Any condition possibly affecting drug absorption (eg, gastrectomy).
• A positive urine drug screen at Screening or Day 0.
• History of regular alcohol consumption exceeding 14 drinks/week for men (1 drink = 5 ounces (150 mL) of wine or 12 ounces (360 mL) of beer or 1.5 ounces (45 mL) of hard liquor) within 6 months of Screening.
• Positive cotinine screen at Screening or Day 0.
• Treatment with an investigational drug within 30 days or 5 half-lives preceding the first dose of study medication (excluding [C-11]PF-04621053).
• 12-lead ECG demonstrating QTc >450 msec at Screening. If QTc exceeds 450 msec, the ECG should be repeated two more times and the average of the three QTc values should be used to determine the subject's eligibility.
• Use of prescription or nonprescription drugs and dietary supplements within 7 days or 5 half-lives (whichever is longer) prior to the first dose of study medication. Herbal supplements must be discontinued 28 days prior to the first dose of study medication.
• Chronic (every day) use of a histamine (H1, H2) inhibitor(s) within 3 months before screening.