Fostemsavir Plus Optimized Background Therapy May Be Viable for Multidrug-Resistant HIV

Pills on Hiv / aids paper background.
Researchers assessed the safety and efficacy of fostemsavir plus optimized background therapy among heavily treatment-experienced patients with multidrug-resistant HIV infection.

Treatment with fostemsavir plus optimized background therapy (OBT) may be a viable treatment option in heavily treatment-experienced (HTE) patients with multidrug-resistant (MDR) HIV infection, according to results of a study in Clinical Therapeutics.

Researchers performed a systematic literature review from January 2003 to February 2021 to identify studies that assessed the relative efficacy and safety of fostemsavir plus OBT in HTE patients with MDR HIV infection. They used matching-adjusted indirect comparison (MAIC) analyses to compare outcomes of safety and efficacy among the included studies.

A total of 3 studies and respective comparators were identified for the analysis. After adjustment, all patient populations had similar mean ages at baseline (range, 45.5-51.0 years), and a similar number of men. Patients included across studies also had similar HIV viral loads, CD4+ cell counts, and antiretroviral susceptibility scores.

At week 24, treatment with fostemsavir plus OBT were associated with a nonsignificant increased rate of virologic suppression (HIV-1 RNA load, <50 copies/mL) compared with ibalizumab plus OBT (odds ratio [OR], 1.44; 95% CI, 0.74-2.80; P = .284). Fostemsavir plus OBT also increased the rate of virologic suppression at weeks 48 (OR, 1.34; 95% CI, 0.78-2.30; P =.297) and 96 (OR, 3.26; 95% CI, 2.08-5.11; P < .001) compared with OBT alone.

Further analysis performed at week 48 showed a greater but nonsignificant increase in the mean CD4+ cell count among patients who received fostemsavir plus OBT vs OBT alone (mean difference [MD], 26.86 cells/mm3; 95% CI, -10.79 to 64.52; P = .162).

The risk for adverse events requiring subsequent treatment discontinuation at week 24 was low, as was the risk of mortality among the adjusted (OR, 0.11; 95% CI, 0.02-0.54) and unadjusted (OR, 0.19; 95% CI, 0.05-0.74) study populations.

Fostemsavir plus OBT as well as ibalizumab plus OBT demonstrated comparable effects on patients’ mean CD4+ cell count, with increases of approximately 65 cells/mm3 observed between baseline and week 24 (MD, 7.05 cells/mm3; 95% CI, -60.88 to 74.98; P = .834)

Limitations included the lack of adjustment and measurement of potential systematic differences among each study’s population that may have affected treatment responses.

“Interpretation of these results and application to health technology assessment and economic evaluation require careful consideration of the therapies likely to be available to HTE people with [MDR] HIV-1 and their resistance profiles to understand what the true comparator would be if fostemsavir were not available,” The researchers concluded.

Disclosure: This study was supported by ViiV Healthcare. Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Anderson S-J, van Doornewaard A, Turner M, et al. Comparative efficacy and safety of fostemsavir in heavily treatment-experienced people with HIV-1. Clin Ther. Published online May 21, 2022. doi:10.1016/j.clinthera.2022.04.007