GS-US-311-1089 Study

Gallant J. CROI 2016, Abs. 29 & Lancet HIV. 2016;3:e158-65 ; Raffi F. J Acquir Immune Defic Syndr. 2017;75:226-31

Type of ARV Trial
Switch studies in virologically suppressed patients
» Switch TDF to TAF


  • In this randomised double-blind study, switch of patients on F/TDF
    + 3rd agent with suppressed viral load for F/TAF + continuation
    of 3rd agent
    • Is non-inferior at W48 and W96 for maintaining virologic suppression (HIV-1 RNA < 50 c/mL)
    • in rare cases of virologic failure, the risk of resistance emergence is low (1 case of M184V on F/TAF), none after W48
    • Is associated with a similar clinical and biological tolerance
    • Leads to improvement of renal parameters: increase in eGFR and decrease in proteinuria, n o renal discontinuations or renal tubulopathy
      in F/TAF group
    • Improves bone mineral density: increase on F/TAF with significant difference of changes at W48 vs F/TDF and c ontinuing increase in hip and spine BMD after W48
    • Increases lipid parameters, with no change in the total cholesterol total: HDL-cholesterol ratio
    • Similar safety findings by 3rd agent


Randomisation stratified on 3rd agent (boosted PI or other)
* F/TAF: 200/10 mg if boosted PI, 200/25 mg if other


  • Primary: proportion of patients maintaining HIV RNA < 50 c/mL at W48 (ITT, snapshot) ; non-inferiority if lower margin of a two-sided 95% CI for the difference = -10%, > 95% power
  • Secondary with multiple adjustments: percentage change in hip and spine bone mineral density

Baseline characteristics and outcome

Virologic outcome at W48 (ITT, snapshot)

Difference (95% CI) = 1.3% (-2.5 to 5.1)

HIV-1 RNA < 50 c/mL at W48 according to 3rd agent, %

  • Virologic success was similar between treatment groups for the subgroups of age, sex, race, and study drug adherence
  • Mean changes in CD4 at W48 ‒
    • + 20/mm3 F/TAF
    • + 21/mm3 F/TDF

Adverse events, N (%)

Discontinuation for adverse event, laboratory abnormalities grade 3-4 (D0-W96)

Mean change in bone mineral density through W96 (%, 95% CI)

Bone mineral density status changes through W48

  • The distribution of the bone mineral density status (normal, osteopenia, osteoporosis) adjusted for baseline status was significantly different between treatment groups at W48
    • at the hip (p = 0.012)
    • and at the spine (p = 0.037)
  • Driven by a higher percentage of subjects in the F/TAF group with an improvement in BMD status (i.e. osteopenia to normal, osteoporosis to normal or osteopenia), and correspondingly, a lower percentage of subjects in the F/TAF with worsening BMD status (i.e. normal to osteopenia or osteoporosis, or osteopenia to osteoporosis)

Change in renal biomarkers at W96

  • Discontinuation for renal adverse event:
    • F/TAF = 0
    • F/TDF = 2 (creatinine increase = 1, renal tubular disorder = 1)

Safety by 3rd Agent

Median fasting lipids W48 versus baseline (mg/dL)