High viral suppression feasible with BIC/FTC/TAF + rifampicin in adults with HIV, TB

Twice-daily treatment with bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) resulted in high viral suppression among people with HIV and tuberculosis (TB) who were on rifampicin-based therapy, according to the INSIGHT* trial presented at CROI 2024.

“BIC/FTC/TAF is widely prescribed in the US and other settings but is not currently available in Africa and other resource-limited settings. Moreover, it is not included in the WHO treatment guidelines, and data gaps exist regarding its expanded use in some settings, including individuals with TB,” said Dr Anushka Naidoo from the Center for the AIDS Programme of Research in South Africa in Durban, South Africa.

“Of the 10 million TB infections recorded globally in 2022, 6–8 percent of these are HIV-positive, 59 percent of which were reported in South Africa ... However, the efficacy, safety, and pharmacokinetics (PK) of BIC/FTC/TAF have not been evaluated in people with HIV and TB taking rifampicin,” she noted.

The phase IIB, noncomparative, open-label INSIGHT study analysed 122 ART-naïve and non-naïve adults (median age 35 years, 35 percent female) with HIV and TB who were on rifampicin for <8 weeks. Participants were randomized in a 2:1 ratio to receive twice-daily BIC/FTC/TAF (BIC arm; n=80) or once-daily dolutegravir/tenofovir disoproxil fumarate/lamivudine (DTG/TDF/3TC) plus DTG 50 mg at night (DTG arm; n=42) for 24 weeks.

In the intention-to-treat FDA snapshot analysis, patients treated with either BIC/FTC/TAF or DTG/TDF/3TC showed similar rates of viral suppression (defined as HIV-1 RNA <50 copies/mL) at week 24 (95 percent in each group). [CROI 2024, abstract 211]

In the per-protocol analysis, viral suppression rates were also high and comparable between the BIC/FTC/TAF and DTG/TDF/3TC groups, at 97 percent each.

In terms of safety, both treatment arms had similar rates of grade 3 adverse events (AEs; 38 percent [BIC/FTC/TAF] vs 36 percent [DTG/TDF/3TC]).

Serious AEs occurred in 11 patients in the BIC arm and seven patients in the DTG arm. However, none of these AEs led to treatment discontinuations, withdrawals, or drug switches, according to Naidoo.

With regard to the preliminary PK data of BIC, the mean trough concentration (Ctau) was 0.397 mg/L for BIC 50 mg twice daily with rifampicin at weeks 4 and 12 and 2.29 mg/L for BIC 50 mg once daily without rifampicin at week 32. As expected, BIC Ctau was reduced during TB treatment with rifampicin, but most remained above IQ, said Naidoo.

“Overall, BIC/FTC/TAF dosed twice daily with rifampicin showed high efficacy in people with HIV and TB through week 24,” said Naidoo.

“The safety, PK, and virologic response data support the use of BIC/FTC/TAF in people with HIV and TB, and we hope this opens a pathway for inclusion in WHO guidelines and access to TB endemic settings,” Naidoo stated.