Study to Evaluate Efficacy and Safety of Darunavir/Cobicistat/Emtricitabine/Tenofovir Alafenamide (D/C/F/TAF) Regimen Versus Boosted Protease Inhibitor (bPI) Along With Emtricitabine/Tenofovir Disoproxil Fumarate (FTC/TDF) Regimen in Virologically-Suppressed, HIV-1 Infected Participants

Virologic rebound was defined as: confirmed plasma human immunodeficiency virus - 1 (HIV-1) Ribonucleic Acid (RNA) level greater than or equal to (>=)50 copies per milliliter (copies/mL) up to, and including the upper bound of the Week 48 window (ie, 54 weeks) and last available on-treatment (single) HIV-1 RNA >=50 copies/mL at premature discontinuation (irrespective of reason). Percentage of participants with virologic rebound were reported.

Virologic rebound was defined as: confirmed plasma HIV-1 RNA >=20 copies/mL up to, and including the upper bound of the Week 48 window (ie, 54 weeks) and last available on-treatment (single) HIV-1 RNA >=20 copies/mL at premature discontinuation (irrespective of reason). Percentage of participants with virologic rebound were reported.

Virologic rebound was defined as: confirmed plasma HIV-1 RNA >=200 copies/mL up to, and including the upper bound of the Week 48 window (ie, 54 weeks) and last available on-treatment (single) HIV-1 RNA >=200 copies/mL at premature discontinuation (irrespective of reason). Percentage of participants with virologic rebound were reported.

Virologic rebound was defined as: confirmed plasma HIV-1 RNA >=50 copies/mL up to, and including the upper bound of the Week 48 window (ie, 54 weeks) and last available on-treatment (single) HIV-1 RNA >=50 copies/mL at premature discontinuation (irrespective of reason). Here Kaplan-Meier estimates percentage of participants with non-virologic rebound at week 48.

An AE is any untoward medical occurrence in participant who received study drug without regard to possibility of causal relationship. Grade 3 (Severe) events were symptoms causing inability to perform usual social & functional activities. Grade 4 (Life-threatening) events were symptoms causing inability to perform basic self-care functions or medical or operative intervention indicated to prevent permanent impairment, persistent disability, or death.

Change from baseline in serum creatinine levels at Weeks 24 and 48 was assessed.

Change from baseline in eGFRcr (by Cockcroft-Gault formula) was assessed at Weeks 24 and 48. eGFRcr according to the Cockcroft Gault formula- Male: (140 - age in years)*(weight in kilogram [kg])/72*(serum creatinine in milligram per deciliter [mg/dL])=eGFRcr (milliliter per minute [mL/min]); Female: (140 - age in years)*(weight in kg)/72*(serum creatinine in mg/dL)*0.85=eGFRcr (mL/min).

Change from baseline in eGFRcr (by CKD-EPI) was assessed at Weeks 24 and 48. eGFRcr per CKD-EPI formula - Female: 1) Serum creatinine (Scr) less than or equal to (<=)0.7 mg/dL: 144*(Scr/0.7)^-0.329*0.993age; 2) Scr greater than (>)0.7 mg/dL: 144*(Scr/0.7)^-1.209*0.993age. Male: 1) Scr <=0.9 mg/dL: 141*(Scr/0.9)^-0.411*0.993age; 2) Scr >0.9 mg/dL: 141*(Scr/0.9)^-1.209*0.993age.

Change from baseline in eGFRcyst (by CKD-EPI) was assessed at Weeks 24 and 48. eGFRcyst according to the CKD-EPI formula - 1) Serum Cystatin C (Scyst) <=0.8 mg/L: 133*(Scyst/0.8)^-0.499*0.996age (*0.932 if female); 2) Scyst >0.8 mg/L: 133*(Scyst/0.8)^-1.328*0.996age (*0.932 if female).

Change from baseline in UACR and UPCR was assessed at Weeks 24 and 48. Lower levels of albumin or protein in the urine indicates better proximal tubular function.

Change from baseline in URBPCR and UB2MGCR was assessed at Weeks 24 and 48. Retinol binding protein is a marker of proximal tubular function.

Percent change from baseline in urine FEPO4 was assessed at Weeks 24 and 48.

Percentage of participants with virologic response based on HIV-1 RNA <20, <50, and <200 copies/mL threshold were analyzed at Week 48 using FDA snapshot approach. FDA Snapshot approach analysis was based on the last observed viral load data: virologic response was defined as HIV-1 RNA <20/50/200 copies/mL (observed case).

Percentage of participants with virologic response based on HIV-1 RNA <20, <50, and <200 copies/mL threshold were analyzed at Week 48 using TLOVR algorithm approach. TLOVR was defined as sustained HIV-1 RNA <20/50/200 copies/mL.

Change from baseline in CD4+ cell count was assessed at Weeks 24 and 48.

Treatment adherence (defined as adherence of >95%) was assessed by the drug accountability cumulative through Week 48 (Approach 1).

Treatment adherence (defined as adherence of >95%) was assessed by the drug accountability cumulative treatment adherence up to time point where not more than one bottle was missing, or if available, through Week 48, whichever came sooner (Approach 2).

HIV-1 genotypes were analyzed from samples of participants with confirmed virologic rebound (virologic rebound was defined as: confirmed HIV-1 RNA >=50 copies/mL up to, and including the upper bound of the Week 48 window) and with HIV-1 RNA value >=400 copies/mL or who discontinued with last HIV-1 RNA >=400 copies/mL. Number of participants who developed resistance to any of the study drug was determined.

Predose (trough) plasma concentration (C0h) of darunavir was determined. Pharmacokinetic (PK) data was only analyzed for participants in the D/C/F/TAF group as per planned analysis.

Percent change from baseline in bone biomarkers: P1NP and CTX was assessed at Weeks 24 and 48.

Percent change from baseline in bone biomarker: PTH was assessed at Weeks 24 and 48.

Percent change from baseline in bone biomarker: 25-hydroxy vitamin D was assessed at Weeks 24 and 48.

Percent change from baseline in spine and hip BMD was assessed at Weeks 24 and 48.

Change from baseline in spine, hip, and femoral neck BMD T-Score was assessed at Week 24 and 48. T-score values >= -1.0 were considered normal, T-score values < -1.0 to -2.5 indicate osteopenia and T-score values < -2.5 indicate osteoporosis.

Virologic rebound was defined as: confirmed plasma HIV-1 RNA level >=20 copies/mL up to and including Week 96, last available on-treatment (single) HIV-1 RNA >=20 copies/mL at premature discontinuation (irrespective of reason), and last available on-treatment HIV-1 RNA >=20 copies/mL at the study cutoff of Week 96 (that is, any last viral load [re]test having occurred no later than 6 weeks after Week 96). Percentage of participants with virologic rebound were reported.

Virologic rebound was defined as: confirmed plasma HIV-1 RNA level >=50 copies/mL up to and including Week 96, last available on-treatment (single) HIV-1 RNA >=50 copies/mL at premature discontinuation (irrespective of reason), and last available on-treatment HIV-1 RNA >=50copies/mL at the study cutoff of Week 96 (that is, any last viral load [re]test having occurred no later than 6 weeks after Week 96). Percentage of participants with virologic rebound were reported.

Virologic rebound was defined as: confirmed plasma HIV-1 RNA level >=200 copies/mL up to and including Week 96, last available on-treatment (single) HIV-1 RNA >=200 copies/mL at premature discontinuation (irrespective of reason), and last available on-treatment HIV-1 RNA >=200 copies/mL at the study cutoff of Week 96 (that is, any last viral load [re]test having occurred no later than 6 weeks after Week 96). Percentage of participants with virologic rebound were reported.

Here Kaplan-Meier estimates percentage of participants with non-virologic rebound at Week 96.

Percentage of participants with virologic response based on HIV-1 RNA <20, <50, and <200 copies/mL threshold were analyzed at Week 96 using FDA snapshot approach. FDA Snapshot approach analysis was based on the last observed viral load data: virologic response was defined as having last available HIV-1 RNA <20/50/200 copies/mL (observed case).

Percentage of participants with virologic response based on HIV-1 RNA <20, <50, and <200 copies/mL threshold were analyzed at Week 96 using TLOVR algorithm approach. TLOVR was defined as sustained HIV-1 RNA <20/50/200 copies/mL.

Percentage of participants with virologic failure based on HIV-1 RNA >=20, >=50, and >=200 copies/mL threshold were analyzed at Week 96 using FDA snapshot approach. FDA Snapshot approach analysis was based on the last observed viral load data: virologic failure was defined by the FDA snapshot approach as having last available HIV-1 RNA >=20/50/200 copies/mL at Week 96; virologic failure - leading to discontinuation; virologic failure - discontinued due to other reason and last available HIV-1 RNA >=20/50/200 copies/mL.

Change from reference in CD4+ cell count was assessed at Week 96. The change from reference in CD4+ count at a given time point is defined as: CD4+ at a given time point minus reference CD4+. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

HIV-1 genotypes were analyzed from samples of participants with confirmed virologic rebound in case they had HIV-1 RNA values >=400 copies/mL at failure or at later time points, including participants who discontinued with last HIV-1 RNA >=400 copies/mL. Virologic rebound was defined as: confirmed plasma HIV-1 RNA level >=20 copies/mL up to and including Week 96, last available on-treatment (single) HIV-1 RNA >=20 copies/mL at premature discontinuation (irrespective of reason), and last available on-treatment HIV-1 RNA >=20 copies/mL at the study cutoff of Week 96 (that is, any last viral load [re]test having occurred no later than 6 weeks after Week 96). Number of participants who developed resistance to any of the study drug (DRV, FTC, and TFV/TAF) were reported.

Treatment adherence (defined as adherence of >95%) was assessed by the drug accountability cumulative through Week 96 (Approach 1).

Treatment adherence (defined as adherence of >95%) was assessed by the drug accountability cumulative treatment adherence up to time point where not more than one bottle was missing, or if available, through Week 96, whichever came sooner (Approach 2).

AE is any untoward medical occurrence in participant who received study drug without regard to possibility of causal relationship. Grade 3 (Severe) events were symptoms causing inability to perform usual social & functional activities. Grade 4 (Life-threatening) events were symptoms causing inability to perform basic self-care functions or medical or operative intervention indicated to prevent permanent impairment, persistent disability, or death. SAE is any AE that results in: death, persistent or significant disability/incapacity, requires inpatient hospitalization or prolongation of existing hospitalization, is life-threatening experience, is a congenital anomaly/birth defect and may jeopardize participant and/or may require medical or surgical intervention to prevent one of the outcomes listed above.

Change from reference in serum creatinine levels at Week 96 was assessed. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in eGFRcr (by Cockcroft-Gault formula) was assessed at Week 96. eGFRcr according to the Cockcroft Gault formula- Male: (140 - age in years)*(weight in kilogram [kg])/72*(serum creatinine in milligram per deciliter [mg/dL])=eGFRcr (milliliter per minute [mL/min]); Female: (140 - age in years)*(weight in kg)/72*(serum creatinine in mg/dL)*0.85=eGFRcr (mL/min). For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in eGFRcr (by CKD-EPI) was assessed at Week 96. eGFRcr per CKD-EPI formula - Female: 1) Serum creatinine (Scr) less than or equal to (<=)0.7 mg/dL: 144*(Scr/0.7)^-0.329*0.993^age; 2) Scr greater than (>)0.7 mg/dL: 144*(Scr/0.7)^-1.209*0.993^age. Male: 1) Scr <=0.9 mg/dL: 141*(Scr/0.9)^-0.411*0.993^age; 2) Scr >0.9 mg/dL: 141*(Scr/0.9)^-1.209*0.993^age. . For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in eGFRcyst (by CKD-EPI) was assessed at Week 96. eGFRcyst according to the CKD-EPI formula - 1) Serum Cystatin C (Scyst) <=0.8 mg/L: 133*(Scyst/0.8)^-0.499*0.996^age (*0.932 if female); 2) Scyst >0.8 mg/L: 133*(Scyst/0.8)^-1.328*0.996^age (*0.932 if female). For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in UACR was assessed at Week 96. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in URBPCR was assessed at Week 96. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in UPCR was assessed at Week 96. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Change from reference in UB2MGCR was assessed at Week 96. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Percent change from reference in FEPO4 at Week 96 was reported. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Percent change from reference in serum P1NP levels at Week 96 was reported. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Percent change from reference in serum CTX at Week 96 was reported. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Percent change from reference in PTH at Week 96 was reported. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Percent change from reference in 25-OH Vitamin D at Week 96 were reported. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

The BMD is the amount of mineral in gram per square centimeter of bone, which was assessed by DXA scan. Positive values are "best values" and negative values are "worst values" of change. Percent change from reference in hip and spine BMD was assessed. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

BMD status was assessed using BMD T-scores; normal bone status was defined by a BMD T-score >= -1, osteopenia by a T-score >= -2.5 to <-1.0, and osteoporosis by a T-score <-2.5. For the D/C/F/TAF group, reference is the comparative treatment phase baseline as in Week 48 analysis (Reference 1). For the Switch to D/C/F/TAF (late switch) group, the last value prior to the switch was used as reference (reference 2).

Virologic rebound is defined as participants who show confirmed HIV-1 RNA >=50 copies/mL, or for which the last available (single) HIV-1 RNA value on treatment was >=50 copies/mL. Here, Kaplan-Meier estimates (%) of non-virologic rebound at every 6 months interval are presented.

Percentage of participants with non-treatment failure by Kaplan-Meier Estimates were reported. Treatment failure was defined as having either protocol-defined virologic rebound or having discontinued for reasons other than alternate access to D/C/F/TAF (or other antiretroviral [ARV]).

Percentage of participants with HIV RNA <50, <20, <200 copies/mL post Week 96 to end of extension were reported.

The immunologic change was determined by Cluster of CD4+ cell count. CD4+ cell count post-Week 96 to end of extension were assessed.

Treatment adherence (defined as adherence of >95%) was assessed by the drug accountability and was calculated cumulative from start of treatment/switch to last study drug intake by determination of the cumulative treatment adherence in participants who returned all dispensed bottles prior to or at the last visit in the study from Week 96 to end of extension.

AE is any untoward medical occurrence in participant who received study drug without regard to possibility of causal relationship. Grade 3 (Severe) events were symptoms causing inability to perform usual social & functional activities. Grade 4 (Life-threatening) events were symptoms causing inability to perform basic self-care functions or medical or operative intervention indicated to prevent permanent impairment, persistent disability, or death. SAE is any AE that results in: death, persistent or significant disability/incapacity, requires inpatient hospitalization or prolongation of existing hospitalization, is life-threatening experience, is a congenital anomaly/birth defect and may jeopardize participant and/or may require medical or surgical intervention to prevent one of the outcomes listed above.