Extended Safety Study of Tenofovir Disoproxil Fumarate (TDF) Among HIV-1 Negative Men

The purpose of this study is to examine safety and tolerability of daily tenofovir use in HIV-uninfected men.

This study will assess the clinical and behavioral safety and tolerability of oral daily TDF use as pre-exposure prophylaxis (PrEP) to prevent HIV infection in uninfected men.

Eligibility Criteria:
Inclusion Criteria:

* Healthy biologic male (male at birth)
* 18-60 years of age
* HIV-1 negative by licensed, commercially available, FDA-approved whole blood rapid enzyme immunoassay (EIA) at screening and enrollment
* Reports any anal sex with a man in the last 12 months
* Able to understand and pass comprehension assessment questionnaire
* Able to understand and sign a written informed consent form, which must be obtained prior to initiation of study procedures
* Able to understand English
* Adequate renal function: calculated creatinine clearance of at least 70 mL/min
* Hepatic transaminases (AST and ALT) less than or equal to 2x upper limit of normal (ULN)
* Total bilirubin less than or equal to 1.5 mg/dL
* Absolute neutrophil count at least 1,500/mm3;
* Platelets at least 100,000/mm3;
* Hemoglobin at least 9.5 g/dL
* Serum amylase less than or equal to 1.5 x ULN
* Biochemical profile: within normal limits for serum phosphorus, potassium, sodium, and calcium.
* Hepatitis B surface antigen negative
* Normal urine dipstick or urinalysis (UA)

Exclusion Criteria:

* Active untreated syphilis
* Current uncontrolled hypertension (blood pressure \> 160/100 mmHg)
* Mutually monogamous for \> one year with a known HIV antibody negative partner
* History of chronic renal disease, known osteoporosis, osteomalacia, or osteopenia
* Current or expected participation in other longitudinal HIV behavioral or biomedical research study
* Current HIV antiretroviral use
* Receiving or planning to receive on-going therapy with any nephrotoxic agents or experimental/investigational agents
* Previous or expected requirements for the administration of immunosuppressive/ immunomodulatory therapy (e.g. chronic systemic steroids, interferon, interleukins, chemotherapy, radiation).
* Evidence of a gastrointestinal malabsorption syndrome or chronic nausea or vomiting which may confer an inability to receive an orally administered medication.
* Current alcohol or substance abuse judged by the investigator to potentially interfere with participant compliance.
* Imminently life-threatening medical conditions (malignancy, immunosuppressive disease \[e.g. lymphoma\]), or other serious disease or conditions (e.g. cardiovascular, renal, diabetes) within the last 5 years or that are unstable and/or require chronic medication that would impede compliance with study requirements and complicate the interpretation of adverse events
* Expected to be non-compliant with study visits or planning to move within 24 months to an area where the study will not be conducted
* Any other clinical or social condition, prior therapy, occupation, or other responsibility, that, in the opinion of the investigator, would interfere with, or serve as a contraindication to study participation or compliance with the dosing requirements.