Heavily treatment-experienced (HTE) individuals with HIV-1 infection may soon have another treatment option, according to the results of a recent phase 3 clinical trial presented at the 16th European AIDS Conference in Milan, Italy this week.
Although great strides have been made in treating HIV, resulting in a significant decrease in mortality for those who infected, the incidence of treatment failure and resistance
to the antivirals that treat the infecting is increasing. Those patients who experience these outcomes have limited, effective antiviral options available to them due to mutations in the virus, as well as their own comorbidities, and tolerability, and safety issues with medications that are available for them. Additional treatment options are imperative in this growing population.
As a result, ViiV Healthcare is testing a new medication aimed at the HTE population. The medication, fostemsavir, “is a first in class, HIV-1 attachment inhibitor that blocks viral attachment to CD4 by binding to gp120, acting at the first step of the viral life cycle,” according to ViiV
. A recent phase 3 trial, BRIGHTE (NCT02362503), evaluated the safety and efficacy of fostemsavir in HTE adults with HIV-1 infection. The results of the BRIGHTE phase 3 study showed that after 1 week of treatment, HTE patients who received fostemsavir, added to a failing regimen, had a greater reduction in viral load than patients on placebo.
A total of 371 patients who had “documented resistance, intolerability, and/or contraindication to all antiretroviral (ARV) agents in at least 4 of the 6 available ARV classes,” were enrolled in the study, according to ViiV. Those patients in the randomized cohort were required to have at least 1, but no more than 2 “fully active ARV classes remaining at baseline and were unable to form a viable ARV regimen out of their remaining agents,” according to the study description.
Furthermore, “patients were randomized 3:1 to add blinded fostemsavir or blinded placebo (n=272) to their current failing regimen for 8 days of functional monotherapy. Patients without any remaining fully active approved ARVs (n=99) were assigned to the non-randomized cohort and received open-label fostemsavir plus optimized background therapy on day 1. The primary endpoint of the study was mean change in log10 HIV-1 RNA between day 1 and day 8 for the randomized cohort. Beyond the 8-day blinded period, all patients in the randomized cohort received open-label fostemsavir plus optimized background therapy. Key secondary endpoints include durability of response at weeks 24, 48 and 96, as well as safety and emergence of viral resistance.”
According to the study results, “after 1 week of blinded, randomized treatment, all patients received fostemsavir and an optimized background regimen. 54% of patients in the randomized cohort achieved virologic suppression (<40 c/mL) at 24 weeks of treatment with fostemsavir plus optimized background therapy. Most patients who received fostemsavir experienced at least 1 adverse event by week 24; the most frequently reported Grade 2-4 adverse events related to fostemsavir treatment were transient headache (2%), diarrhea (2%) and nausea (4%).”
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