The purpose of this study is to estimate the pharmacokinetics (PK) of 3 different modified-release formulations of lersivirine and compare it to the PK of the immediate-release tablet. The effect of food on the PK of one of the modified-release tablets will also be assess along with the safety and tolerability of each treatment.

Inclusion Criteria:

• Body Mass Index (BMI) of 17.5 to 30.5 kg/m2; and a total body weight >50 kg (110 lbs).
• Subjects who are willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures.

Exclusion Criteria:

• History of regular alcohol consumption exceeding 14 drinks/week for females or 21 drinks/week for males (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;
• Treatment with an investigational drug within 60 days (or as determined by the local requirement, whichever is longer) or 5 half-lives preceding the first dose of study medication;
• 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.