ViiV announces phase 3 study switching to dolutegravir/3TC dual therapy from TAF-containing ART

Simon Collins, HIV i-Base

On 8 February 2018, ViiV Healthcare announced plans for a new phase 3 switch study using dual therapy of dolutegravir/3TC. [1]

The new study, called TANGO, plans to randomise 550 HIV positive people on stable ART containing tenofovir alafenamide (TAF) to either continue current treatment or switch to dual therapy using dolutegravir/3TC. The study will have sites in the US, Europe, Australia and Japan.

This will become the eighth phase 3 study using dolutegravir/3TC dual therapy. It will be a non-inferiority study with a primary endpoint of viral suppression (<50 copies/mL) at week 48.

A footnote in the press release notes that the TANGO study is not yet registered on


While the research question is important, the timing of this announcement seems rushed, coming only a few hours after US approval for bictegravir/emtricitabine/TAF in the FDC Biktarvy. [2]

TAF is integrated into all new Gilead FDCs and is currently used to justify a higher price compared to tenofovir DF (which recently came off patent).


  1. ViiV press release. ViiV Healthcare launches eighth phase III study in two-drug regimen programme for HIV-1 treatment. (08 February 2018).
  2. U.S. Food and Drug Administration approves Gilead’s Biktarvy (bictegravir, emtricitabine, tenofovir alafenamide) for treatment of HIV-1 infection. (07 February 2018).

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