# P-370. Real-World Data on Fostemsavir in People Living with HIV: A Retrospective Chart Review

## TL;DR

This study examines how well fostemsavir works in real-world settings for HIV patients with drug-resistant strains, showing improved virus control and immune recovery.

## Contribution

Provides real-world evidence of fostemsavir's efficacy and safety in treatment-experienced HIV patients with multidrug resistance.

## Key findings

- Viral load decreased significantly over 12 months, reaching a mean of 53 copies/mL.
- CD4 counts increased from 439 to 619 cells/mm³ by month 12.
- High adherence and minimal adverse effects were observed in most patients.

## Abstract

Patients with multidrug-resistant HIV (Human Immunodeficiency Virus) face limited treatment options, increasing their risk of virologic failure. Fostemsavir, a novel attachment inhibitor, has shown efficacy and safety in clinical trials, but real-world data is lacking. We aimed to evaluate virologic suppression, immunologic response, and safety outcomes in treatment-experienced individuals in a real-world clinical setting.Trends in CD4 Count and HIV Viral Load Over 12 Months in Patients Receiving Fostemsavir

Trends in CD4 Count and HIV Viral Load Over 12 Months in Patients Receiving Fostemsavir

We conducted a retrospective chart review of patients living with HIV >18 years old in a Ryan White funded HIV clinic in Newark , NJ who were treated with Fostemsavir for more than 6 months. Data on viral load, CD4 counts, adverse effects, and adherence were collected and descriptive statistics was used to analyze outcomes over 12 months. Primary outcomes were virologic suppression (HIV RNA < 20 copies/mL) and CD4 count change from baseline. Secondary outcomes assessed adherence, adverse effects, and reasons for discontinuation.

17 patients met the inclusion criteria, with a mean age of 57.2 years. The majority were male gender (70.6%). 58.8% were Black or African American, 17.6% White, and 23.5% identified as other races. At baseline, the mean viral load was 56,402 copies/mL, which declined to 400 copies/mL at month 3, 84 copies/mL at month 6, and 53 copies/mL at month 12. Mean CD4 count increased from 439 cells/mm³ at baseline to 492 cells/mm³ at month 3, remained stable at 491 cells/mm³ at month 6, and rose further to 619 cells/mm³ by month 12 as shown in Figure 1. Virologic suppression was achieved in most patients by month 12. Adherence was high with 82.4% fully compliant, 11.8% intermittently compliant, and 5.9% non-compliant. Adverse effects were minimal; 76% reported none, while 11.8% experienced muscle wasting, and 5.9% each reported insomnia or arthralgia. Fostemsavir was discontinued in two patients: due to virologic failure (5.9%), oral intolerance (5.9%).

Fostemsavir demonstrated effective virologic suppression and immune recovery, with a favorable safety profile, in a real-world cohort of treatment-experienced HIV patients. These findings support its clinical utility. Ongoing research in larger populations will build on these findings to further characterize long-term outcomes.

Jihad Slim, MD, FACP, gilead: Honoraria|merck: Honoraria|Thera: Honoraria|ViiV: Honoraria