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SWITCHING TO BICTEGRAVIR/EMTRACITABINE/TENOFOVIR ALAFENIMIDE (B/F/TAF) IN WOMEN
Cissy Kityo1, Debbie Hagins2, Ellen Koenig3, Anchalee Avihingsanon4, Ploenchan Chetchotisakd5, Khuanchai Supparatpinyo6, Natalya Gankina7, Vadim Pokrovsky8, Evgenly Voronin9, Jeffrey L. Stephens10, Edwin DeJesus11, Hui Wang12, Erin Quirk12, Hal Martin12, Tariro Makadzange12
1Joint Clinical Research Centre, Kampala, Uganda,2Chatham CARE Center, Savannah, GA, USA,3Instituto Dominicano de Estudios Virológicos, Santo Domingo, Dominican Republic,4Thai Red Cross AIDS Research Center, Bangkok, Thailand,5Srinagarind Hospital, Khon Kaen, Thailand,6Chiang Mai University, Chiang Mai, Thailand,7Krasnoyarsk Territorial Center for Prevention and Control of AIDS and Infectious Diseases, Krasnoyarsk, Russian Federation,8Center for Prevention and Control of AIDS, Moscow, Russian Federation,9Ministry of Health, Saint-Petersburg, Russian Federation,10Mercer University, Macon, GA, USA,11Orlando Immunology Center, Orlando, FL, USA,12Gilead Sciences, Inc, Foster City, CA, USA
The unboosted integrase inhibitor containing single-tablet regimen (bictegravir/emtricitabine/tenofovir alafenamide, B/F/TAF) has shown efficacy and safety in HIV-1 infected patients. Bictegravir is a novel, unboosted INSTI that has been coformulated with F/TAF in an STR that has shown high rates of suppression with no resistance in phase 3 studies of treatment naïve patients. We now report Week 24 (W24) safety and efficacy of switching to B/F/TAF versus staying on baseline regimen (SBR) [elvitegravir (E)/cobicistat (C)/F/TAF, E/C/F/tenofovir disoproxil fumarate (TDF) or atazanavir (ATV)+ritonavir (RTV)+F/TDF] in an all-women, international multi-centre, randomized, open-label, phase 3 trial.
HIV‑1 infected, virologically suppressed women on a protease inhibitor or boosted elvitegravir-containing regimen were randomized (1:1) to switch to B/F/TAF or stay on baseline regimen (SBR). The primary efficacy endpoint was the proportion of women with HIV‑1 RNA >50 copies (c)/mL at W48 with 4% noninferiority margin (FDA snapshot). A secondary efficacy endpoint of HIV-1 RNA <50 c/mL at W24 is reported here. Other secondary endpoints include safety (adverse events (AEs), laboratory abnormalities). This interim W24 efficacy and safety analysis was pre-specified.
We randomized and treated 470 women (234 B/F/TAF, 236 SBR (E/C/F/TAF n=125; E/C/F/TDF n=98; ATV+RTV+FTC/TDF n=13). Demographic and baseline characteristics were balanced; overall 37% black, 28.3% white, 21.7% Asian, median age was 39 years and CD4 count was 686 cells/μl. At W24 98.7% in the B/F/TAF group vs. 99.2% in the SBR group achieved HIV-1 RNA <50 c/mL (difference -0.4% (95%CI: 3.0% to 1.9%, p=0.68). Two participants, one in each group, had resistance testing; neither developed resistance to any study drug. No participant discontinued treatment due to an AE; there were no differences between groups in grade 3 or 4 treatment-emergent AEs (3.8% B/F/TAF, 5.5% SBR group). Grade 3 or 4 laboratory abnormalities occurred in 17% of participants on B/F/TAF and 18% on SBR.
At W24 women who switched to B/F/TAF maintained high levels of virologic suppression with comparable efficacy to those who remained on a baseline regimen. B/F/TAF was safe and well tolerated. This analysis supports the efficacy and safety of B/F/TAF in women observed in other B/F/TAF phase 2 and 3 studies.