Gilead's bictegravir, Descovy fixed-dose combination HIV therapy meets main goals of Phase III studies

Gilead Sciences on Tuesday reported that four late-stage studies investigating a fixed-dose combination of the integrase strand transfer inhibitor bictegravir and Descovy (emtricitabine/tenofovir alafenamide) for the treatment of HIV-1 infection met their primary endpoints of non-inferiority. Gilead chief scientific officer Norbert Bischofberger remarked "based on the results…the combination of bictegravir and [Descovy] could represent an important advance in triple-therapy treatment for a broad range of HIV patients," with the company noting that a US marketing application is planned for the second quarter, with a filing in Europe targeted for the third quarter.

In Study 1489, 600 patients with HIV were randomised to treatment with bictegravir and Descovy, and ViiV Healthcare's Triumeq (abacavir/dolutegravir/lamivudine), while the same number of patients were treated with ‎bictegravir and Descovy or ViiV's Tivicay plus Descovy in Study 1490. In both studies, the primary endpoint was the proportion of patients with HIV-1 RNA levels of less than 50 copies/mL at week 48, while the lower bound of the 95 percent confidence interval for non-inferiority was 12 percent.

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Meanwhile, in Study 1844, 520 patients who were virologically suppressed on Triumeq were randomised to remain on their current treatment or switch to bictegravir and Descovy. In Study 1878, the same number of HIV-positive patients who were virologically suppressed on a boosted protease inhibitor of Johnson & Johnson's Prezista (darunavir) or Bristol-Myers Squibb's Reyataz (atazanavir) in combination with a nucleoside/nucleotide backbone of abacavir/lamivudine or Gilead's Truvada (emtricitabine/tenofovir disoproxil) were randomised to continue current treatment or switch to bictegravir and Descovy. In both trials, the main goal was the proportion of patients with HIV-1 RNA levels of at least 50 copies/mL, while the lower bound of the 95 percent confidence interval for non-inferiority was 4 percent.

In addition to achieving the main goal in all four studies, Gilead noted that no patients assigned to treatment with bictegravir or Tivicay developed treatment-emergent resistance. The drugmaker said that one patient treated with a protease inhibitor in Study 1878 developed an abacavir resistance mutation. The company plans to submit data from the studies for presentation at research meetings this year.

Descovy was cleared by regulators in the US and EU last year for the treatment of HIV-1 infection in adults and children aged 12 and older.

For related analysis, read ViewPoints: Gilead banking on ‘good enough’ being good enough with bictegravir. For related analysis on the HIV market, see also Analysts Notes: How are market barriers changing the market share split for HIV drugs?

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