TOPLINE

In heavily treatment-experienced people with multidrug-resistant HIV-1 in France, fostemsavir-based antiretroviral therapy maintained viral suppression in 91% of those already suppressed and achieved suppression in 63% of those with detectable virus, while ibalizumab-based regimens achieved suppression in 36%.

METHODOLOGY

• In a retrospective observational study in France, researchers analyzed outcomes of heavily treatment-experienced people with HIV-1 who initiated fostemsavir- or ibalizumab-based regimens.
• They included 81 patients who had received many prior antiretroviral regimens and often harbored multidrug-resistant virus and had ≥ 3 months on therapy: 70 started fostemsavir (median age, 57 years; 76% men) and 11 started ibalizumab (median age 39 years; 36% men).
• Baseline genotypic resistance testing was required for study inclusion; genotypic testing and drug-level monitoring at treatment failure were available for only a subset of patients.
• Virologic failure was defined as two consecutive plasma viral loads (VL) ≥ 50 copies/mL, nonvirologic response as < 1 log10 VL decrease or failure to suppress by week 24.
• Median follow-up duration was 20 months for fostemsavir recipients and 7 months for ibalizumab recipients.

TAKEAWAY

• At last follow-up, 78% of fostemsavir recipients had plasma VL < 50 copies/mL. Virologic suppression persisted in 91% who were aviremic at baseline; 63% who were viremic at baseline achieved virologic suppression.
• Virologic failure occurred in 11% of fostemsavir recipients overall. Emergence of gp120 mutations associated with fostemsavir resistance occurred in one case, and suboptimal temsavir plasma concentrations were detected in two failing patients.
• Among ibalizumab recipients, 36% achieved VL < 50 copies/mL at the last follow-up visit, and 46% experienced virologic failure.
• At failure on ibalizumab, one patient acquired a new capsid mutation (N74D), and suboptimal plasma concentrations of the oral companion antiretrovirals were observed in three of five assessable participants.

IN PRACTICE

"People who are HTE [heavily treatment-experienced] and virologically suppressed maintain virologic control after 2 years to switching to an FTR-based regimen, which represents a valuable option for treatment optimization," the authors of the study wrote.

SOURCE

The study was led by Karl Stefic, Université de Tours, INSERM 1259 MAVIVHe, CHU de Tours, Service de Virologie, Tours, France. It was published online on August 14 in Open Forum Infectious Diseases.

LIMITATIONS

Researchers did not include a comparator group. The study lacked clinical data and had incomplete data on resistance at failure. Longitudinal sampling was not conducted.

DISCLOSURES

The study received support from the Agence Nationale de Recherche sur le sida et les hépatites virales I Maladies Infectieuses Emergentes. Several authors reported receiving honoraria and travel grants from MSD, Gilead Sciences, and ViiV Healthcare. One author reported receiving grants to her institution from ViiV Healthcare and honoraria and travel grants from ViiV Healthcare and Gilead Sciences. Additional author disclosures are reported in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.