SUSTAINED EFFICACY, SAFETY, AND IMMUNOLOGICAL IMPROVEMENT OVER 7 YEARS WITH FOSTEMSAVIR-BASED REGIMENS IN INDIVIDUALS WITH HIV-1 AND LIMITED TREATMENT OPTIONS IN LATIN AMERICA

Fostemsavir (FTR), a prodrug of temsavir, is a novel antiretroviral with a unique mechanism of action targeting both virion-bound and soluble gp120. Phase III results from the BRIGHTE study demonstrated that FTR-based regimens provide robust HIV-1 viral suppression, sustained increases in CD4+ T-cell counts, and a favorable safety profile over 5 years. This report presents the week 336 (7-year) outcomes for participants from Latin America in the randomized cohort (RC). BRIGHTE is a phase 3 multicenter study conducted in 22 countries, including Latin America (Argentina, Brazil, Chile, Colombia, and Peru). The RC comprised 272 participants with one or two remaining fully active antiretroviral classes, who received FTR or placebo for 8 days, followed by open-label FTR plus optimized background therapy (OBT). At week 336, 37 Latin American participants remained enrolled at selected study sites. Among Latin American participants, at week 336, 78% (29/37) maintained virologic suppression in the RC (HIV-1 RNA < 40 copies/mL). No new safety signals were reported. The median CD4+ T-cell count at week 336 increased by +280 cells/mm³ (baseline: 111 cells/mm³). The mean CD4+/CD8+ ratio increased from 0.16 to 0.6, and the mean percentage of CD4+ T-cells rose from 9.7% to 12.65% by week 336. Median levels of inflammatory biomarkers (sCD14, sCD163, D-dimer) were generally reduced for all pro-inflammatory markers assessed from baseline to week 336. These long-term findings demonstrate that fostemsavir-based regimens maintain durable efficacy and safety, with sustained immunological improvement and broad reductions in inflammation among Latin American individuals with limited treatment options over 7 years. These results are consistent with those observed in the broader BRIGHTE study population through week 336.