Background and Importance The new intramuscular antiretroviral treatments (IM-ART), cabotegravir-rilpivirine, have represented a breakthrough in reducing stigma and improving adherence among HIV patients. However, it is necessary to understand how their real-world use impacts patient outcomes.

Aim and Objectives To assess the effectiveness and safety of IM-ART in real-world settings and investigate their impact on analytical parameters.

Material and Methods A retrospective observational study conducted from January to September 2023, including all patients treated with LA-ART with at least three doses. Demographic data (age, gender), treatment-related information (previous ART and presence of resistance mutations (RM)), clinical data (LDL-cholesterol, HDL-cholesterol, creatinine, GOT, GPT, alkaline phosphatase, GGT, total bilirubin, calcium, and phosphorus before and after IM-ART), and effectiveness data (HIV-RNA copies (CV), CD4 count, and CD4/CD8 ratio before and after starting IM-ART) were collected. Adverse events (AE) and pain assessed on the Visual Analog Scale (VAS) during the first two administrations were recorded. Paired Student’s t-test and Wilcoxon signed-rank test were used for statistical analysis of differences between pre- and post-LA-ART variables, depending on the distribution. Statistical analysis was performed using Stata/IC16.1 software.

Results Sixty-six patients (93.9% men) were analysed. Median age: 42 years (IQR:38–46). 50,0% were receiving triple therapy before the switch, and 27.6% had at least one RM, which did not affect IM-ART. Three patients had CV>30 copies/mL before starting LA-ART. All patients included maintained CV<30 copies/mL during the study period. Statistically significant differences were observed in LDL-cholesterol (p=0.0193) and CD4 (p=0.0035) between pre- and post-IM-ART values.

All patients experienced at least one AE, with injection site reactions being the most frequent (98.5%). The observed AEs included: general malaise (36.7%), asthenia (13.6%), fever (12.1%), diarrhoea (9.1%), headache (7.6%), sleep disturbances (6.1%), nausea (3.0%), and others (4.5%). One patient discontinued IM-ART due to AE.

Differences in pain assessed on the VAS were observed between rilpivirine vs cabotegravir administration [0.9 (95% CI: 0.3–1.5; p=0.0029)] and between the second vs first administration: rilpivirine [1.6 (95% CI: 0.5–2.7; p=0.0042)]; cabotegravir [1.6 (95% CI: 0.6–2.6; p=0.0032)].

Conclusion and Relevance LA-ART has demonstrated effectiveness and acceptable safety in real-world data, consistent with the results of the ATLAS and FLAIR studies. Longer-term studies are needed to evaluate the evolution of CD4 counts, LDL levels and pain.

Conflict of Interest No conflict of interest.