MONTREAL – Interim results of ALLIANCE, the first head-to-head trial comparing two different tenofovir-containing antiretroviral regimens for the treatment of and (HBV) coinfection, demonstrate the superiority of / /tenofovir alafenamide (B/F/TAF) over plus tenofovir disoproxil fumarate (DTG + F/TDF), researchers reported at a meeting of the International AIDS Society.
, with more HBV DNA suppression and significantly more seroconversion, reported lead investigator Anchalee Avihingsanon, MD, PhD, at a press conference during the meeting. Dr. Avihingsanon heads the medical department of the HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT) at the Thai Red Cross AIDS Research Centre, Bangkok.
The ongoing phase 3, multicountry study has 48-week results for 243 participants, who were HIV/HBV coinfected and treatment naive. All subjects received three pills of ART per day, with blinded randomization to (active B/F/TAF + placebo DTG + placebo TDF/FTC or placebo B/F/TAF + active DTG + active TDF/FTC). The primary endpoints at 48 weeks were proportion of participants with HIV-1 RNA less than 50 copies/mL and plasma HBV DNA less than 29 IU/mL.
For the HIV endpoint, results showed both the B/F/TAF and DTG + F/TDF arms had high rates of suppression (95% and 91%, respectively, P = .21), but the B/F/TAF group had significantly higher rates of HBV DNA suppression (63% vs 43.4%, P = .0023) and HBeAg seroconversion (23.3% vs. 11.3%), with numerically higher, but not statistically significant differences in HBsAg loss/seroconversion (12.6% vs. 5.8% and 8.4% vs. 3.3%), HBeAg loss (25.6% vs 14.4%), and ALT normalization (73.3% vs 55.3%).
No participant developed treatment-emergent HIV-1 drug resistance while on B/F/TAF, and there were few study-drug–related AEs or discontinuations, she reported.
“There is hardly any good reason to give the two-pill DTG regimen over single-tablet BTG/TAF/FTC in HBV-coinfected people living with HIV [PLWH],” commented Babafemi Taiwo, MD, chief of infectious diseases and professor of medicine at Northwestern University in Evanston, Ill., who was not involved in the research. “This gives me confidence to prescribe bictegravir/TAF/FTC, which has the added advantage of being a single-tablet formulation, to HBV coinfected PLWH,” he said in an interview. However, he added, the results “call for some head-scratching since TAF is not known to be better than TDF for HBV treatment in persons without HIV.”
“The lower response rate of the TDF group is still poorly understood,” agreed Dr. Avihingsanon, emphasizing that “HBV and HIV/HBV are not the same, and TDF and TAF are also different. TAF has slightly more drug-drug interactions than TDF. I guess its end product in the liver might be higher. What is exciting to me is that there was such a high rate of HBsAg loss and HBs seroconversion in HIV/HBV coinfection, which is totally different from HBV monoinfection [< 1% at 48 weeks]. For me as an investigator, this important finding has additional benefit to further explore the immunologic outcome for possible HBV cure strategy.” She said the study remains blinded until week 96, at which time further data may shed light on this question.
“Perhaps a larger study would help clarify impact of TAF versus TDF on measures that did not achieve statistical significance in this study. Long-term follow up to better understand the clinical implications of these results could be helpful as well,” Dr. Taiwo added.
The study was funded by Gilead. Dr. Avihingsanon reported no relevant disclosures. Dr. Taiwo disclosed that he has served as consultant to ViiV/GlaxoSmithKline, Johnson & Johnson, and Merck, and consulted for Gilead on COVID.
A version of this article first appeared on.