Renal, Endocrine, and Bone Changes in Response to Treatment with Coformulated Emtricitabine-Tenofovir for Pre-Exposure HIV Prophylaxis (PrEP) in HIV Uninfected Young Men Who Have Sex with Men, a Sub-Study of ATN 110 and/or ATN 113

An observational cohort sub-study of subjects enrolled in ATN 110 or ATN 113, and prescribed daily coformulated emtricitabine/tenofovir (FTC/TDF (Truvada�)) as part of ATN 110 or ATN 113, with the primary objective of measuring the magnitude of change in parathyroid hormone (PTH) from baseline to week 48. Renal, endocrine, and bone biochemistry changes and pathophysiology were explored as secondary objectives. Subjects were HIV uninfected YMSM, inclusive of transgender women, and were to be followed for at least 48 weeks; seronegative subjects in the Extension Phase of ATN 110 or ATN 113 were followed for an additional 48 weeks in the Extension Phase of ATN 117.