The single-tablet regimen of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (a.k.a. E/C/F/TDF, known by the brand name Stribild) was found effective against HIV-2 in a small trial published in Clinical Infectious Diseases. HIV-2 is a globally less-common (and less-studied) genetic variant of HIV found mostly in West Africa.
The open-label trial was conducted in Senegal. Thirty participants living with HIV-2 -- 80% of whom were women -- with median CD4 cell counts of 408 cells/mm3 and no prior antiretroviral treatment started the study drug, and 29 completed all 48 weeks. At that endpoint, CD4 cell counts increased by a median of 161 cells/mm3 and the virus was suppressed in 28 (93.3%) of participants. However, 25 people had started out with viral loads of < 50 copies/mL; HIV-2 infection is differentiated from HIV-1 infection in that it generally follows a much slower rate of disease progression and features much lower viral load levels.
In addition to showing the safety and efficacy of integrase-based HIV-2 treatment, the study results suggest that a test-and-treat approach for people diagnosed with HIV-2 "would not be unreasonable," even if the person's viral load is low or undetectable, or if their CD4 cell count is greater than 500 cells/mm3, study authors said. Study sponsors included Gilead Sciences, the manufacturer of Stribild, although sponsors had no influence on study design or the manuscript, according to the study's disclosure section.