Pharmacotherapeutic group: Antivirals for systemic use; antivirals for treatment of HIV infections, combinations. ATC code: J05AR18.
Mechanism of action
Elvitegravir is an HIV‑1 integrase strand transfer inhibitor (INSTI). Integrase is an HIV‑1 encoded enzyme that is required for viral replication. Inhibition of integrase prevents the integration of HIV‑1 deoxyribonucleic acid (DNA) into host genomic DNA, blocking the formation of the HIV‑1 provirus and propagation of the viral infection.
Cobicistat is a selective, mechanism‑based inhibitor of cytochrome P450 (CYP) enzymes of the CYP3A subfamily. Inhibition of CYP3A‑mediated metabolism by cobicistat enhances the systemic exposure of CYP3A substrates, such as elvitegravir, where bioavailability is limited and half‑life is shortened by CYP3A‑dependent metabolism.
Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) and nucleoside analogue of 2'‑deoxycytidine. Emtricitabine is phosphorylated by cellular enzymes to form emtricitabine triphosphate. Emtricitabine triphosphate inhibits HIV replication through incorporation into viral DNA by the HIV reverse transcriptase (RT), which results in DNA chain‑termination. Emtricitabine has activity against HIV‑1, HIV‑2, and HBV.
Tenofovir alafenamide is a nucleotide reverse transcriptase inhibitor (NtRTI) and phosphonamidate prodrug of tenofovir (2'‑deoxyadenosine monophosphate analogue). Tenofovir alafenamide is permeable into cells and due to increased plasma stability and intracellular activation through hydrolysis by cathepsin A, tenofovir alafenamide is more efficient than tenofovir disoproxil in concentrating tenofovir in peripheral blood mononuclear cells (PBMCs) (including lymphocytes and other HIV target cells) and macrophages. Intracellular tenofovir is subsequently phosphorylated to the pharmacologically active metabolite tenofovir diphosphate. Tenofovir diphosphate inhibits HIV replication through incorporation into viral DNA by the HIV RT, which results in DNA chain‑termination. Tenofovir has activity against HIV‑1, HIV‑2, and HBV.
Antiviral activity in vitro
Elvitegravir, emtricitabine, and tenofovir alafenamide demonstrated synergistic antiviral activity in cell culture. Antiviral synergy was maintained for elvitegravir, emtricitabine, and tenofovir alafenamide when tested in the presence of cobicistat.
The antiviral activity of elvitegravir against laboratory and clinical isolates of HIV‑1 was assessed in lymphoblastoid cells, monocyte/macrophage cells, and peripheral blood lymphocytes and the 50% effective concentration (EC50) values were in the range of 0.02 to 1.7 nM. Elvitegravir displayed antiviral activity in cell culture against HIV‑1 clades A, B, C, D, E, F, G, and O (EC50 values ranged from 0.1 to 1.3 nM) and activity against HIV‑2 (EC50 of 0.53 nM).
Cobicistat has no detectable antiviral activity against HIV‑1 and does not antagonise the antiviral effects of elvitegravir, emtricitabine, or tenofovir.
The antiviral activity of emtricitabine against laboratory and clinical isolates of HIV‑1 was assessed in lymphoblastoid cell lines, the MAGI CCR5 cell line, and PBMCs. The EC50 values for emtricitabine were in the range of 0.0013 to 0.64 µM. Emtricitabine displayed antiviral activity in cell culture against HIV‑1 clades A, B, C, D, E, F, and G (EC50 values ranged from 0.007 to 0.075 µM) and showed strain specific activity against HIV‑2 (EC50 values ranged from 0.007 to 1.5 µM).
The antiviral activity of tenofovir alafenamide against laboratory and clinical isolates of HIV‑1 subtype B was assessed in lymphoblastoid cell lines, PBMCs, primary monocyte/macrophage cells and CD4+‑T lymphocytes. The EC50 values for tenofovir alafenamide were in the range of 2.0 to 14.7 nM. Tenofovir alafenamide displayed antiviral activity in cell culture against all HIV‑1 groups (M, N, and O), including subtypes A, B, C, D, E, F, and G (EC50 values ranged from 0.10 to 12.0 nM) and showed strain specific activity against HIV‑2 (EC50 values ranged from 0.91 to 2.63 nM).
Resistance
In vitro
Reduced susceptibility to elvitegravir is most commonly associated with the primary integrase mutations T66I, E92Q, and Q148R. Additional integrase mutations observed in cell culture selection included H51Y, F121Y, S147G, S153Y, E157Q, and R263K. HIV‑1 with the raltegravir‑selected substitutions T66A/K, Q148H/K, and N155H showed cross‑resistance to elvitegravir.
No in vitro resistance can be demonstrated with cobicistat due to its lack of antiviral activity.
Reduced susceptibility to emtricitabine is associated with M184V/I mutations in HIV‑1 RT.
HIV‑1 isolates with reduced susceptibility to tenofovir alafenamide express a K65R mutation in HIV‑1 RT; in addition, a K70E mutation in HIV‑1 RT has been transiently observed. HIV‑1 isolates with the K65R mutation have low‑level reduced susceptibility to abacavir, emtricitabine, tenofovir, and lamivudine.
In treatment‑naïve patients
In a pooled analysis, genotyping was performed on plasma HIV‑1 isolates from antiretroviral‑naïve patients receiving Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead in Phase 3 studies GS‑US‑292‑0104 and GS‑US‑292‑0111 with HIV‑1 RNA ≥ 400 copies/mL at confirmed virologic failure, Week 144, or time of early study drug discontinuation. Up to Week 144, the development of one or more primary elvitegravir, emtricitabine, or tenofovir alafenamide resistance‑associated mutations was observed in HIV‑1 isolates from 12 of 22 patients with evaluable genotypic data from paired baseline and Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead treatment‑failure isolates (12 of 866 patients [1.4%]) compared with 12 of 20 treatment‑failure isolates from patients with evaluable genotypic data in the E/C/F/TDF treatment group (12 of 867 patients [1.4%]). Of the HIV‑1 isolates from 12 patients with resistance development in the Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead group, the mutations that emerged were M184V/I (n = 11) and K65R/N (n = 2) in RT and T66T/A/I/V (n = 2), E92Q (n = 4), Q148Q/R (n = 1) and N155H (n = 2) in integrase. Of the HIV‑1 isolates from 12 patients with resistance development in the E/C/F/TDF group, the mutations that emerged were M184V/I (n = 9), K65R/N (n = 4), and L210W (n = 1) in RT and E92Q/V (n = 4), and Q148R (n = 2), and N155H/S (n = 3) in integrase. Most HIV‑1 isolates from patients in both treatment groups who developed resistance mutations to elvitegravir developed resistance mutations to both emtricitabine and elvitegravir.
In phenotypic analyses of patients in the final resistance analysis population, 7 of 22 patients (32%) had HIV‑1 isolates with reduced susceptibility to elvitegravir in the Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead group compared with HIV‑1 isolates from 7 of 20 patients (35%) in the E/C/F/TDF group, HIV‑1 isolates from 8 patients (36%) had reduced susceptibility to emtricitabine in the Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead group compared with HIV‑1 isolates from 7 patients (35%) in the E/C/F/TDF group. One patient in the Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead group (1 of 22 [4.5%]) and 2 patients in the E/C/F/TDF group (2 of 20 [10%]) had reduced susceptibility to tenofovir.
In virologically suppressed patients
Three patients with emergent HIV‑1 resistance to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were identified (M184M/I; M184I+E92G; M184V+E92Q) up to Week 96 in a clinical study of virologically suppressed patients who switched from a regimen containing emtricitabine/tenofovir disoproxil and a third agent (GS‑US‑292‑0109, n = 959).
In patients co‑infected with HIV and HBV
In a clinical study of HIV virologically suppressed patients co‑infected with chronic hepatitis B, who received Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead for 48 weeks (GS‑US‑292‑1249, n = 72), 2 patients qualified for resistance analysis. In these 2 patients, no amino acid substitutions associated with resistance to any of the components of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were identified in HIV‑1 or HBV.
Cross‑resistance in HIV‑1 infected, treatment‑naïve or virologically suppressed patients
Elvitegravir‑resistant viruses show varying degrees of cross‑resistance to the INSTI raltegravir depending on the type and number of mutations. Viruses expressing the T66I/A mutations maintain susceptibility to raltegravir, while most other patterns showed reduced susceptibility to raltegravir. Viruses expressing elvitegravir or raltegravir resistance mutations maintain susceptibility to dolutegravir.
Emtricitabine‑resistant viruses with the M184V/I substitution were cross‑resistant to lamivudine, but retained sensitivity to didanosine, stavudine, tenofovir, and zidovudine.
The K65R and K70E mutations result in reduced susceptibility to abacavir, didanosine, lamivudine, emtricitabine, and tenofovir, but retain sensitivity to zidovudine.
Clinical data
HIV‑1 infected, treatment-naïve patients
In studies GS‑US‑292‑0104 and GS‑US‑292‑0111, patients were randomised in a 1:1 ratio to receive either Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead (n = 866) once daily or elvitegravir 150 mg/cobicistat 150 mg/emtricitabine 200 mg/tenofovir disoproxil (as fumarate) 245 mg (E/C/F/TDF) (n = 867) once daily. The mean age was 36 years (range 18‑76), 85% were male, 57% were White, 25% were Black, and 10% were Asian. Nineteen percent of patients were identified as Hispanic/Latino. The mean baseline plasma HIV‑1 RNA was 4.5 log10 copies/mL (range 1.3‑7.0) and 23% had baseline viral loads > 100,000 copies/mL. The mean baseline CD4+ cell count was 427 cells/mm3 (range 0‑1,360) and 13% had a CD4+ cell count < 200 cells/mm3.
Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead demonstrated statistical superiority in achieving HIV‑1 RNA < 50 copies/mL when compared to E/C/F/TDF at Week 144. The difference in percentage was 4.2% (95% CI: 0.6% to 7.8%). Pooled treatment outcomes at 48 and 144 weeks are shown in Table 3.
Table 3: Pooled virologic outcomes of studies GS‑US‑292‑0104 and GS‑US‑292‑0111 at Weeks 48 and 144a,b
| | Week 48 | Week 144 |
| Elvitegravir/Cobicistat/ Emtricitabine/Tenofovir Alafenamide Gilead (n = 866) | E/C/F/TDF (n = 867) | Elvitegravir/Cobicistat/ Emtricitabine/Tenofovir Alafenamide Gilead (n = 866) | E/C/F/TDF (n = 867) |
HIV‑1 RNA < 50 copies/mL | 92% | 90% | 84% | 80% |
Treatment difference | 2.0% (95% CI: ‑0.7% to 4.7%) | 4.2% (95% CI: 0.6% to 7.8%) |
HIV‑1 RNA ≥ 50 copies/mLc | 4% | 4% | 5% | 4% |
No virologic data at Week 48 or 144 window | 4% | 6% | 11% | 16% |
Discontinued study drug due to AE or deathd | 1% | 2% | 1% | 3% |
Discontinued study drug due to other reasons and last available HIV‑1 RNA < 50 copies/mLe | 2% | 4% | 9% | 11% |
Missing data during window but on study drug | 1% | < 1% | 1% | 1% |
Proportion (%) of patients with HIV‑1 RNA < 50 copies/mL by subgroup | | | | |
Age < 50 years ≥ 50 years | 716/777 (92%) 84/89 (94%) | 680/753 (90%) 104/114 (91%) | 647/777 (83%) 82/89 (92%) | 602/753 (80%) 92/114 (81%) |
Sex Male Female | 674/733 (92%) 126/133 (95%) | 673/740 (91%) 111/127 (87%) | 616/733 (84%) 113/133 (85%) | 603/740 (81%) 91/127 (72%) |
Race Black Non‑black | 197/223 (88%) 603/643 (94%) | 177/213 (83%) 607/654 (93%) | 168/223 (75%) 561/643 (87%) | 152/213 (71%) 542/654 (83%) |
Baseline viral load ≤ 100,000 copies/mL > 100,000 copies/mL | 629/670 (94%) 171/196 (87%) | 610/672 (91%) 174/195 (89%) | 567/670 (85%) 162/196 (83%) | 537/672 (80%) 157/195 (81%) |
Baseline CD4+ cell count < 200 cells/mm3 ≥ 200 cells/mm3 | 96/112 (86%) 703/753 (93%) | 104/117 (89%) 680/750 (91%) | 93/112 (83%) 635/753 (84%) | 94/117 (80%) 600/750 (80%) |
HIV‑1 RNA < 20 copies/mL | 84.4% | 84.0% | 81.1% | 75.8% |
Treatment difference | 0.4% (95% CI: ‑3.0% to 3.8%) | 5.4% (95% CI: 1.5% to 9.2%) |
E/C/F/TDF = elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate
a Week 48 window was between Day 294 and 377 (inclusive); Week 144 window was between Day 966 and 1,049 (inclusive).
b In both studies, patients were stratified by baseline HIV‑1 RNA (≤ 100,000 copies/mL, > 100,000 copies/mL to ≤ 400,000 copies/mL, or > 400,000 copies/mL), by CD4+ cell count (< 50 cells/µL, 50‑199 cells/µL, or ≥ 200 cells/µL), and by region (US or ex‑US).
c Includes patients who had ≥ 50 copies/mL in the Week 48 or 144 window; patients who discontinued early due to lack or loss of efficacy; patients who discontinued for reasons other than an adverse event (AE), death or lack or loss of efficacy and at the time of discontinuation had a viral value of ≥ 50 copies/mL.
d Includes patients who discontinued due to AE or death at any time point from Day 1 through the time window if this resulted in no virologic data on treatment during the specified window.
e Includes patients who discontinued for reasons other than an AE, death or lack or loss of efficacy; e.g., withdrew consent, loss to follow‑up, etc.
The mean increase from baseline in CD4+ cell count was 230 cells/mm3 in Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead‑treated patients and 211 cells/mm3 in E/C/F/TDF‑treated patients (p = 0.024) at Week 48, and 326 cells/mm3 in Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead‑treated patients and 305 cells/mm3 in E/C/F/TDF‑treated patients (p = 0.06) at Week 144.
HIV‑1 infected virologically suppressed patients
In Study GS‑US‑292‑0109, the efficacy and safety of switching from either efavirenz (EFV)/emtricitabine (FTC)/tenofovir disoproxil, FTC/tenofovir disoproxil plus atazanavir (boosted by either cobicistat or ritonavir), or E/C/F/TDF to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were evaluated in a randomised, open‑label study of virologically suppressed (HIV‑1 RNA < 50 copies/mL) HIV‑1 infected adults (n = 1,436). Patients must have been stably suppressed (HIV‑1 RNA < 50 copies/mL) on their baseline regimen for at least 6 months and had HIV‑1 with no resistance mutations to any of the components of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead prior to study entry. Patients were randomised in a 2:1 ratio to either switch to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead at baseline (n = 959), or stay on their baseline antiretroviral regimen (n = 477). Patients had a mean age of 41 years (range 21‑77), 89% were male, 67% were White, and 19% were Black. The mean baseline CD4+ cell count was 697 cells/mm3 (range 79‑1,951). Patients were stratified by prior treatment regimen. At screening, 42% of patients were receiving FTC/tenofovir disoproxil plus atazanavir (boosted by either cobicistat or ritonavir), 32% of patients were receiving E/C/F/TDF, and 26% of patients were receiving EFV/FTC/tenofovir disoproxil.
Switching from a tenofovir disoproxil‑based regimen to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead was superior in maintaining HIV‑1 RNA < 50 copies/mL compared to staying on the baseline regimen (Table 4).
Table 4: Virologic outcomes of Study GS‑US‑292‑0109 at Weeks 48a and 96b
| | Week 48 | Week 96 |
| | Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead (n = 959) | Baseline regimen (n = 477) | Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead (n = 959) | Baseline regimen (n = 477) |
HIV‑1 RNA < 50 copies/mL | 97% | 93% | 93% | 89% |
Treatment difference | 4.1% (95% CI: 1.6% to 6.7%, p < 0.001c) | 3.7% (95% CI: 0.4% to 7.0%, p < 0.017c) |
HIV‑1 RNA ≥ 50 copies/mLd | 1% | 1% | 2% | 2% |
No virologic data at Week 48/ Week 96 window | 2% | 6% | 5% | 9% |
Discontinued study drug due to AE or deathe | 1% | 1% | 1% | 3% |
Discontinued study drug due to other reasons and last available HIV‑1 RNA < 50 copies/mLf | 1% | 4% | 3% | 6% |
Missing data during window but on study drug | 0% | < 1% | 1% | < 1% |
Proportion (%) of patients with HIV‑1 RNA < 50 copies/mL by prior treatment regimen | | | | |
EFV/FTC/tenofovir disoproxil | 96% | 90% | 90% | 86% |
FTC/tenofovir disoproxil plus boosted atazanavir | 97% | 92% | 92% | 88% |
E/C/F/TDF | 98% | 97% | 96% | 93% |
EFV = efavirenz; FTC = emtricitabine; E/C/F/TDF = elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate
a Week 48 window was between Day 294 and 377 (inclusive).
b Week 96 window was between Day 630 and 713 (inclusive).
c P‑value for the superiority test comparing the percentages of virologic success was from the CMH test stratified by the prior treatment regimen (EFV/FTC/tenofovir disoproxil, FTC/tenofovir disoproxil plus boosted atazanavir, or E/C/F/TDF).
d Includes patients who had ≥ 50 copies/mL in the Week 48 or Week 96 window; patients who discontinued early due to lack or loss of efficacy; patients who discontinued for reasons other than an adverse event (AE), death or lack or loss of efficacy and at the time of discontinuation had a viral value of ≥ 50 copies/mL.
e Includes patients who discontinued due to AE or death at any time point from Day 1 through the time window if this resulted in no virologic data on treatment during the specified window.
f Includes patients who discontinued for reasons other than an AE, death or lack or loss of efficacy; e.g., withdrew consent, loss to follow‑up, etc.
HIV‑1 infected patients with mild to moderate renal impairment
In Study GS‑US‑292‑0112, the efficacy and safety of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were evaluated in an open‑label clinical study of 242 HIV‑1 infected patients with mild to moderate renal impairment (eGFRCG: 30‑69 mL/min). Patients were virologically suppressed (HIV‑1 RNA < 50 copies/mL) for at least 6 months before switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead. The mean age was 58 years (range 24‑82), with 63 patients (26%) who were ≥ 65 years of age. Seventy‑nine percent were male, 63% were White, 18% were Black, and 14% were Asian. Thirteen percent of patients were identified as Hispanic/Latino. At baseline, 80 patients (33%) had eGFRCG < 50 mL/min and 162 patients had eGFRCG ≥ 50 mL/min. At baseline, median eGFR was 56 mL/min. The mean baseline CD4+ cell count was 664 cells/mm3 (range 126‑1,813).
At Week 144, 83.1% (197/237 patients) maintained HIV‑1 RNA < 50 copies/mL after switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead.
In Study GS‑US‑292‑1825, the efficacy and safety of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were evaluated in a single‑arm, open‑label clinical study in which 55 HIV‑1 infected adults with end stage renal disease (eGFRCG < 15 mL/min) on chronic haemodialysis for at least 6 months before switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead. Patients were virologically suppressed (HIV‑1 RNA < 50 copies/mL) for at least 6 months before switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead.
The mean age was 48 years (range 23‑64). Seventy‑six percent were male, 82% were Black and 18% were White. Fifteen percent of patients identified as Hispanic/Latino. The mean baseline CD4+ cell count was 545 cells/mm3 (range 205‑1473). At Week 48, 81.8% (45/55 patients) maintained HIV‑1 RNA < 50 copies/mL after switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead. There were no clinically significant changes in fasting lipid laboratory tests in patients who switched to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead.
Patients co‑infected with HIV and HBV
In open‑label Study GS‑US‑292‑1249, the efficacy and safety of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were evaluated in adult patients co‑infected with HIV‑1 and chronic hepatitis B. Sixty‑nine of the 72 patients were on prior tenofovir disoproxil‑containing antiretroviral therapy. At the start of treatment with Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead, the 72 patients had been HIV suppressed (HIV‑1 RNA < 50 copies/mL) for at least 6 months with or without suppression of HBV DNA and had compensated liver function. The mean age was 50 years (range 28‑67), 92% of patients were male, 69% were White, 18% were Black, and 10% were Asian. The mean baseline CD4+ cell count was 636 cells/mm3 (range 263‑1,498). Eighty‑six percent of patients (62/72) were HBV suppressed (HBV DNA < 29 IU/mL) and 42% (30/72) were HBeAg positive at baseline.
Of the patients who were HBeAg positive at baseline, 1/30 (3.3%) achieved seroconversion to anti‑HBe at Week 48. Of the patients who were HBsAg positive at baseline, 3/70 (4.3%) achieved seroconversion to anti‑HBs at Week 48.
At Week 48, 92% of patients (66/72) maintained HIV‑1 RNA < 50 copies/mL after switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead. The mean change from baseline in CD4+ cell count at Week 48 was ‑2 cells/mm3. Ninety‑two percent (66/72 patients) had HBV DNA < 29 IU/mL using missing = failure analysis at Week 48. Of the 62 patients who were HBV suppressed at baseline, 59 remained suppressed and 3 had missing data. Of the 10 patients who were not HBV suppressed at baseline (HBV DNA ≥ 29 IU/mL), 7 became suppressed, 2 remained detectable, and 1 had missing data.
There are limited clinical data on the use of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead in HIV/HBV co‑infected patients who are treatment‑naïve.
Changes in measures of bone mineral density
In studies in treatment‑naïve patients, Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead was associated with smaller reductions in bone mineral density (BMD) compared to E/C/F/TDF as measured by DXA analysis of hip (mean change: ‑0.8% versus ‑3.4%, p < 0.001) and lumbar spine (mean change: ‑0.9% versus ‑3.0%, p < 0.001) after 144 weeks of treatment.
Improvements in BMD were noted at 96 weeks after switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead from a tenofovir disoproxil‑containing regimen compared to maintaining the tenofovir disoproxil‑containing regimen.
Changes in measures of renal function
In studies in treatment‑naïve patients, Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead was associated with a lower impact on renal safety parameters (as measured after 144 weeks treatment by estimated glomerular filtration rate by Cockcroft‑Gault method, and urine protein to creatinine ratio and after 96 weeks treatment by urine albumin to creatinine ratio) compared to E/C/F/TDF (see also section 4.4). Through 144 weeks of treatment, no subject discontinued Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead due to a treatment‑emergent renal adverse event compared with 12 subjects who discontinued E/C/F/TDF (p < 0.001).
An improved renal safety profile was maintained through Week 96 in patients who switched to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead compared with those who stayed on a tenofovir disoproxil‑containing regimen.
Paediatric population
Study GS‑US‑292‑0106
In Study GS‑US‑292‑0106, the efficacy, safety, and pharmacokinetics of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were evaluated in an open‑label study in HIV‑1 infected, treatment‑naïve adolescents between the ages of 12 to < 18 years, weighing ≥ 35 kg (n = 50) in Cohort 1, in virologically suppressed children between the ages of 7 to < 12 years, weighing > 25 kg (n = 52) in Cohort 2, and in virologically suppressed children between the ages of 3 to 9 years, weighing ≥ 14 to < 25 kg (n = 27) in Cohort 3.
Patients in Cohort 1 had a mean age of 15 years (range 12 to 17), were 44% male, 12% Asian, and 88% Black. At baseline, mean plasma HIV‑1 RNA was 4.6 log10 copies/mL, median CD4+ cell count was 456 cells/mm3 (range: 95 to 1,110), and median CD4+% was 23% (range: 7 to 45%). Overall, 22% had baseline plasma HIV‑1 RNA > 100,000 copies/mL.
At Week 48, the virologic response rate to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead in treatment‑naïve HIV‑1 infected adolescents was similar to response rates in studies of treatment‑naïve HIV‑1 infected adults. In patients treated with Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead, 92% (46/50) achieved HIV‑1 RNA < 50 copies/mL. The mean increase from baseline in CD4+ cell count at Week 48 was 224 cells/mm3. Three patients had virologic failure at Week 48; there was no virologic resistance detected to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead.
Patients in Cohort 2 had a mean age of 10 years (range: 7 to 11), a mean baseline weight of 32 kg (range: 26 to 58), were 42% male, 25% Asian, and 71% Black. At baseline, median CD4+ cell count was 926 cells/mm3 (range: 366 to 1611), and median CD4+% was 38% (range: 23 to 51%).
After switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead, 98% (51/52) of patients in Cohort 2 remained suppressed (HIV‑1 RNA < 50 copies/mL) at Week 48. The mean change from baseline in CD4+ cell count and percentage at Week 48 was ‑66 cells/mm3 and ‑0.6%, respectively. One of 52 patients met the criteria for inclusion in the resistance analysis population through Week 48; no emergent resistance to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead was detected through Week 48.
Patients in Cohort 3 had a mean age of 6 years (range: 3 to 9), a mean baseline weight of 19 kg (range: 15 to 24), were 37% male, 11% Asian, and 89% Black. At baseline, median CD4+ cell count was 1061 cells/mm3 (range: 383 to 2401), and median CD4+% was 37% (range: 24 to 53%).
After switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead, 96% (26/27) of patients in Cohort 3 remained suppressed (HIV-1 RNA < 50 copies/mL) at Week 48. The mean change from baseline in CD4+ cell count and percentage at Week 48 was ‑179 cells/mm3 and 0.2% respectively. One patient had virologic failure at Week 48; no emergent resistance to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead was detected through Week 48.
Study GS‑US‑292‑1515
In Study GS‑US‑292‑1515, the efficacy and safety of Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead were evaluated in an open‑label study in HIV‑1 infected, virologically suppressed adolescents between the ages of 12 and 18 years, weighing ≥ 35 kg (n = 50).
Patients in the study had a median age of 15 years (range: 12 to 17 years), 64% were female and 98% were Black. At baseline, median CD4+ cell count was 742 cells/mm3 (range: 255 to 1,246) and median CD4+% was 34% (range: 21 to 53%).
After switching to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead, 90% (45/50) of patients remained suppressed (HIV‑1 RNA < 50 copies/mL) at Week 48. The mean change from baseline in CD4+ cell count and percentage at Week 48 was ‑43 cells/mm3 and ‑0.1%, respectively. Five subjects had virologic failure through the end of the study; no phenotypic or genotypic resistance to Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Gilead was detected.