Renal, Endocrine, and Bone Changes in Response to FTC/TDF in Uninfected Young Men Who Have Sex With Men (YMSM).

Study Overview
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Brief Summary
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This is a prospective observational cohort sub-study of subjects enrolled in the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) 110 (NCT01772823) or ATN 113 (NCT01769456), which is a prospective interventional trial.

Detailed Description
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This is a prospective observational cohort sub-study of subjects enrolled in the ATN 110 (NCT01772823) or ATN 113 (NCT01769456) study. All subjects will be followed for at least 48 weeks. Subjects who meet specific bone or renal criteria at Week 48 of the ATN 110 (NCT01772823) or ATN 113 (NCT01769456) study will be followed for an additional 48 weeks in the Extension Phase of ATN 110 (NCT01772823) or ATN 113 (NCT01769456) and ATN 117 (NCT01769469). The maximum duration of participation will be 96 weeks. There is no therapeutic intervention specific to this sub-study, and there are no extra study visits required for participation in this sub-study. Questionnaires will be administered and blood and urine samples for laboratory evaluation of potential emtricitabine (FTC)/tenofovir (TDF) (Truvada®) toxicities will be obtained for this sub-study at visits that are required by the ATN 110 (NCT01772823) or ATN 113 (NCT01769456) study. Measurement of bone mineral density (BMD) and bone mineral content (BMC) by dual-energy X-ray absorptiometry (DXA) scan are planned as a part of the ATN 110 (NCT01772823) and ATN 113 (NCT01769456) studies, and results will be utilized for the analysis in this study. This study does not require extra BMD or BMC measurements.

Official Title
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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.

Conditions
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HIV Infection

Intervention / Treatment
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* Drug: FTC/TDF (Truvada®)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Has been enrolled in ATN 110 (NCT01772823) or ATN 113 (NCT01769456) , and Willing and able to provide written informed consent Exclusion Criteria: -Subjects exempted from undergoing DXA scans in ATN 110 (NCT01772823) or ATN 113 (NCT01769456) are not eligible to enroll in ATN 117 (NCT01769469).

Ages Eligible for Study
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Minimum Age: 15 Years
Maximum Age: 22 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Subjects Enrolled in ATN 110 or ATN 113<br>A subset of 100 participants who are enrolled in the ATN 110 or ATN 113 study will be recruited for participation in this study. There is no treatment or intervention for this study; however, all subjects will be on daily coformulated tenofovir/emtricitabine (TDF/FTC (Truvada®)) as part of the ATN 110 or ATN 113 study. | Drug: FTC/TDF (Truvada®)<br>* There are no interventions for this study except that subjects will be administered FTC/TDF (Truvada®) will be administered as part of ATN 110 and ATN 113.<br>* Other names: Truvada®;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Magnitude of Change (Fold Change) in Parathyroid Hormone (PTH) From Baseline to Week 48 | The magnitude of change in PTH will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and Week (wk) 48 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Fibroblast Growth Factor 23 (FGF23), Change From Baseline to Week 48 |  | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Fibroblast Growth Factor 23 (FGF23), Magnitude of Fold Change | The magnitude of change in FGF23 will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Fibroblast Growth Factor 23 (FGF23), Most Extreme Fold Change | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Fibroblast Growth Factor 23 (FGF23), Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: 1,25 Dihydroxy Vitamin D (1,25 OHD), Change From Baseline to Week 48 |  | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: 1,25 OHD, Magnitude of Fold Change | The magnitude of change in 1,25 OHD will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: 1,25 OHD, Most Extreme Fold Change | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: 1,25 OHD, Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Tubular Reabsorption of Phosphate (TRP), Change From Baseline to Week 48 |  | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: TRP, Magnitude of Fold Change | The magnitude of change in TRP will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: TRP, Most Extreme Fold Change | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: TRP, Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Glomerular Filtration Rate (GFR), Change From Baseline to Week 48 |  | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: GFR, Magnitude of Fold Change | The magnitude of change in GFR will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: GFR, Most Extreme Fold Change | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: GFR, Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: PTH, Most Extreme Fold Change | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: PTH, Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Serum Creatinine (SCr), Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: PTH, Slope of the Curve of Baseline to Most Extreme Fold Change | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: FGF23, Slope of the Curve of Baseline to Most Extreme Fold Change | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: 1,25-OHD, Slope of the Curve of Baseline to Most Extreme Fold Change | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: TRP, Slope of the Curve of Baseline to Most Extreme Fold Change | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change From Baseline to Week 48 in Serum Calcium (SCa) | Serum calcium Week 48 difference from baseline | Baseline and wk 48 | 
| Magnitude of Most Extreme Fold Change: Serum Calcium (SCa) | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Time to Most Extreme Fold Change: Serum Calcium (SCa) | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Slope of the Curve of Baseline to Most Extreme Fold Change: Serum Calcium (SCa) | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change From Baseline to Week 48 in Urine Calcium (UCa) / Urine Creatinine (UCr) | Urine Calcium (UCa) / Urine Creatinine (UCr) ratio Week 48 difference from baseline | Baseline and wk 48 | 
| Magnitude of Most Extreme Fold Change: UCa/UCr Ratio | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Time to Most Extreme Fold Change: UCa/UCr Ratio | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Slope of the Curve of Baseline to Most Extreme Fold Change: UCa/UCr Ratio | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change From Baseline to Week 48 in Serum Phosphate (SPO4) | Serum Phosphate (SPO4) Week 48 difference from baseline | Baseline and wk 48 | 
| Magnitude of Most Extreme Fold Change: SPO4 | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Time to Most Extreme Fold Change: SPO4 | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Slope of the Curve of Baseline to Most Extreme Fold Change: SPO4 | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Change From Baseline to Week 48 in Urine Retinol Binding Protein (URBP)/ Urine Creatinine (UCr) | URBP/UCr Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Change From Baseline to Week 48 in Urine Beta-2 Microglobulin (UB2MG) | UB2MG Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Change From Baseline to Week 48 in Urine Protein (UProt) / Urine Creatinine (UCr) | UProt/ UCr Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Change From Baseline to Week 48 in Urine Glucose (UGluc) | UGluc Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Change From Baseline to Week 48 in Serum Creatinine (SCr) | SCr Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Magnitude of Fold Change at Week 48 in Urine Retinol Binding Protein (URBP)/ Urine Creatinine (UCr) | The magnitude of change in URBP/UCr will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Magnitude of Fold Change at Week 48 in Urine Beta-2 Microglobulin (UB2MG) | The magnitude of change in UB2MG will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Magnitude of Fold Change at Week 48 in Urine Protein (UProt)/ Urine Creatinine (UCr) | The magnitude of change in UProt/UCr will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Magnitude of Fold Change at Week 48 in Urine Glucose (UGluc) | The magnitude of change in UGluc will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Magnitude of Fold Change at Week 48 in Serum Creatinine (SCr) | The magnitude of change in SCr will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Change in Glomerular and Renal Tubular Function: Most Extreme Fold Change in Urine Retinol Binding Protein (URBP)/ Urine Creatinine (UCr) | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Glomerular and Renal Tubular Function: Most Extreme Fold Change in UB2MG | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Glomerular and Renal Tubular Function: Most Extreme Fold Change in UProt/UCr | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Glomerular and Renal Tubular Function: Most Extreme Fold Change in UGluc | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Glomerular and Renal Tubular Function: Most Extreme Fold Change in SCr | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Glomerular and Renal Tubular Function: Time to Most Extreme Fold Change in Urine Retinol Binding Protein (URBP)/ Urine Creatinine (UCr) | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Time to Most Extreme Fold Change in UB2MG | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Time to Most Extreme Fold Change in UProt/UCr | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Time to Most Extreme Fold Change in UGluc | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Slope of the Curve of Baseline to Most Extreme Fold Change in Urine Retinol Binding Protein (URBP)/ Urine Creatinine (UCr) | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Slope of the Curve of Baseline to Most Extreme Fold Change in UB2MG | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Slope of the Curve of Baseline to Most Extreme Fold Change in UProt/UCr | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Slope of the Curve of Baseline to Most Extreme Fold Change in UGluc | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Glomerular and Renal Tubular Function: Slope of the Curve of Baseline to Most Extreme Fold Change in Scr | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Change From Baseline to Week 48 in Osteocalcin (OC) | OC Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Change From Baseline to Week 48 in C-Telopeptide (CTX) | CTX Week 48 difference from baseline | Baseline and wk 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Most Extreme Fold Change in Osteocalcin (OC) | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Most Extreme Fold Change in C-telopeptide (CTX) | Most extreme fold change: This is the highest or lowest value measured as fold change from the baseline value of that variable. | Baseline, Weeks 4, 8, 12, 24, 36 and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: OC, Time to Most Extreme Fold Change | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Time to Most Extreme Fold Change in C-telopeptide (CTX) | The time to most extreme fold change is the study week associated with the most extreme fold change or extreme percent change from baseline. | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Slope of the Curve of Baseline to Most Extreme Fold Change in OC | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks 4, 8, 12, 24, 36, and 48 | 
| Change in Renal-endocrine-bone Biochemistry and Pathophysiology: Slope of the Curve of Baseline to Most Extreme Fold Change in CTX | The slope from baseline to most extreme fold change can be expressed as: Slope = [(Most extreme fold change) * (baseline value) - (baseline value)] / [(Time to most extreme fold change) - (time of the baseline value)] | Baseline, Weeks (wks) 4, 8, 12, 24, 36, and 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in PTH, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in PTH, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in FGF23, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in FGF23, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in 1,25 OHD, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in 1,25 OHD, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in Osteocalcin (OC), by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in Osteocalcin (OC), by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in CTX, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in CTX, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in SCr, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in SCr, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in TRP, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in TRP, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in UCa/UCr Ratio, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in UCa/UCr Ratio, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in UB2MG, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in UB2MG, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in UGluc, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in UGluc, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in URBP/UCr Ratio, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in URBP/UCr Ratio, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Percent Change From Baseline to Week 24 in Lumbar Spine BMD, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Percent Change From Baseline to Week 48 in Lumbar Spine BMD, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in Lumbar Spine BMD Z-score, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in Lumbar Spine BMD Z-score, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Percent Change From Baseline to Week 24 in Femoral Neck BMD, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Percent Change From Baseline to Week 48 in Femoral Neck BMD, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 24 in Femoral Neck BMD Z-score, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Change From Baseline to Week 48 in Femoral Neck BMD Z-score, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Area Under the Drug Concentration by Time Curve (AUC): Percent Change From Baseline to Week 24 in Total Body BMC, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, and 24. | Baseline and wk 24 | 
| Area Under the Drug Concentration by Time Curve (AUC): Percent Change From Baseline to Week 48 in Total Body BMC, by Overall Drug Exposure | Overall drug exposure categories were determined based on the overall tertiles of mean AUC dried blood spot (DBS) Red Blood Cell (RBC) Tenofovir Diphosphate (intracellular) (TFV-DP). Comparisons were performed between the high exposure group and the low exposure group. The time points at which data were collected were: weeks 4, 8, 12, 24, 36, and 48. | Baseline and wk 48 | 
| Magnitude of Change in Lumbar Spine BMD at Week 48 | The magnitude of change will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Magnitude of Change in Lumbar Spine BMD Z-score at Week 48 | The magnitude of change will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Baseline and wk 48 | 
| Magnitude of Change in Femoral Neck BMD at Week 48 | The magnitude of change will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Magnitude of Change in Femoral Neck BMD Z-score at Week 48 | The magnitude of change will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Magnitude of Change in Total Body BMC at Week 48 | The magnitude of change will be measured between Baseline and Week 48. For any given variable, at a given time point, the magnitude of change is the fold change compared to the baseline value (if multiplied by 100 would be the percent change from baseline). | Baseline and wk 48 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Change at EPH1 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the first Extension Phase visit (BL - EPH1) | Baseline and wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Change at EPH2 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the second Extension Phase visit (BL - EPH2) | Baseline and wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Change at EPH1 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the first Extension Phase visit (Last - EPH1) | Wk 48 (or last available measurement on study), Wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Change at EPH2 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the second Extension Phase visit (Last - EPH2) | Wk 48 (or last available measurement on study), Wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Z-score Change at EPH1 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the first Extension Phase visit (BL - EPH1). The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Baseline and wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Z-score Change at EPH2 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the second Extension Phase visit (BL - EPH2) The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Baseline and wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Z-score Change at EPH1 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the first Extension Phase visit (Last - EPH1) The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Wk 48 (or last available measurement on study), Wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Lumbar Spine BMD Z-score Change at EPH2 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the second Extension Phase visit (Last - EPH2) The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Wk 48 (or last available measurement on study), Wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Change at EPH1 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the first Extension Phase visit (BL - EPH1) | Baseline and wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Change at EPH2 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the second Extension Phase visit (BL - EPH2) | Baseline and wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Change at EPH1 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the first Extension Phase visit (Last- EPH1) | Wk 48 (or last available measurement on study), Wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Change at EPH2 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the second Extension Phase visit (Last- EPH2) | W 48 (or last available measurement on study), Wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Z-score Change at EPH1 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the first Extension Phase visit (BL - EPH1) The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Baseline and wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Z-score Change at EPH2 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the second Extension Phase visit (BL - EPH2) The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Baseline, Week 96 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Z-score Change at EPH1 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the first Extension Phase visit (Last - EPH1) The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Week 48 (or last available measurement on study), Week 72 | 
| Changes in BMD/BMC in the Extension Phase: Femoral Neck BMD Z-score Change at EPH2 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the second Extension Phase visit (Last - EPH2). The Z-score is the standard deviation around mean bone mineral density, adjusted for sex, age, and race/ethnicity. An average Z-score of zero would be expected in this group of healthy adolescents and young adults. An increase in Z-score would signify acceleration of accrual of bone mass, a positive outcome; a decrease in Z-score would signify either bone loss or failure to accrue the expected amount of bone mass, both of which are adverse outcomes. The Z-score is a normalized measure. | Wk 48 (or last available measurement on study), Wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Total Body BMC Change at EPH1 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the first Extension Phase visit (BL - EPH1) | Baseline and wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Total Body BMC Change at EPH2 From Baseline | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the Baseline measure and the second Extension Phase visit (BL - EPH2) | Baseline and wk 96 | 
| Changes in BMD/BMC in the Extension Phase: Total Body BMC Change at EPH1 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the first Extension Phase visit (Last- EPH1) | Wk 48 (or last available measurement on study), Wk 72 | 
| Changes in BMD/BMC in the Extension Phase: Total Body BMC Change at EPH2 From Week 48 (or Last Visit on Study) | For subjects in the extension phase of the study, the last measured values at the ATN 110 or ATN 113 study week 48 visit will be compared with those measured at the Extension Phase visit 1 (EPH 1, 24 weeks after the ATN 110 or ATN 113 study week 48 visit) and EPH 2 (48 weeks after the ATN 110 or ATN 113 study week 48 visit). This measure shows the difference between the last measure on study and the second Extension Phase visit (Last- EPH2) | Wk 48 (or last available measurement on study), Wk 96 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Tenofovir, Emtricitabine, Truvada, Renal, endocrine, bone changes, HIV prevention, PrEP