Safety of AMD070 When Administered Alone or Boosted With Low-Dose Ritonavir in HIV Uninfected Men

Inclusion Criteria for all participants: * HIV uninfected males in good general health * Normal electrocardiogram (EKG) and lab values * Body weight within 33% of ideal weight for height within 28 days of study entry * Willing to refrain from exercise for 24 hours prior to study entry * Willing to use acceptable forms of contraception Inclusion Criteria for Group 3's Additional Study: * Willing to refrain from consumption of alcohol and grapefruit juice for the duration of the study Exclusion Criteria for all participants: * Prescription medications, herbal supplements, or aspirin within 7 days of study entry * Nonsteroidal anti-inflammatory drugs, over-the-counter medications, and other supplements (including multivitamins) within 1 day of study entry * Active infection or acute illness within 14 days of study entry * Drug or alcohol abuse or dependence * Known sensitivity to AMD070 * History of gastrointestinal bleeding or ulcer * Any medical or psychological condition that, in the opinion of the investigator, would interfere with study participation Exclusion Criteria for Group 3: * Immunizations within 30 days of study entry * Radiation therapy, cytotoxic chemotherapeutic agents, or immunomodulating agents within 30 days of study entry * Chronic diarrhea for more than 4 weeks prior to study entry * Heart conduction abnormalities, heart arrhythmias, cardiomyopathy, any repolarization delay, or other risk factors for heart failure and hypokalemia Exclusion Criteria …