Lipids contained in the plasma membrane of platelets play an important role in platelet function. Modifications in the lipid composition can fluidify or rigidify the environment around embedded receptors, in order to facilitate the access of the receptor by the drug. However, data concerning the lipid composition of platelet plasma membrane need to be updated. In addition, data on the impact of drugs on plasma membrane composition, in particular antiplatelet agents, remain sparse. After isolation of platelet plasma membrane, we assessed, using lipidomics, the effect of ticagrelor, a P2Y12 antagonist, and its active metabolite on the lipid composition of these plasma membranes. We describe the exact lipid composition of plasma membrane, including all sub-species. Ticagrelor and its active metabolite significantly increased cholesterol and phosphatidylcholine ether with short saturated acyl chains 16:0/16:0, and decreased phosphatidylcholine, suggesting overall rigidification of the membrane. Furthermore, ticagrelor and its active metabolite decreased some arachidonylated plasmalogens, suggesting a decrease in availability of arachidonic acid from the membrane phospholipids for synthesis of biologically active mediators. To conclude, ticagrelor and its active metabolite seem to influence the lipid environment of receptors embedded in the lipid bilayer and modify the behavior of the plasma membrane.

Ticagrelor is an antiplatelet agent which is extensively metabolized in an active metabolite: AR-C124910XX. Ticagrelor antagonizes P2Y12 receptors, but recently, this effect on the central nervous system has been linked to the development of dyspnea. Ticagrelor-related dyspnea has been linked to persistently high plasma concentrations of ticagrelor. Therefore, there is a need to develop a simple, rapid, and sensitive method for simultaneous determination of ticagrelor and its active metabolite in human plasma to further investigate the link between concentrations of ticagrelor, its active metabolite, and side effects in routine practice. We present here a new method of quantifying both molecules, suitable for routine practice, validated according to the latest Food and Drug Administration (FDA) guidelines, with a good accuracy and precision (<15% respectively), except for the lower limit of quantification (<20%). We further describe its successful application to plasma samples for a population pharmacokinetics study. The simplicity and rapidity, the wide range of the calibration curve (2–5000 µg/L for ticagrelor and its metabolite), and high throughput make a broad spectrum of applications possible for our method, which can easily be implemented for research, or in daily routine practice such as therapeutic drug monitoring to prevent overdosage and occurrence of adverse events in patients.

Background: Tenofovir disoproxil fumarate is a prodrug of tenofovir diphosphate that exposes patients to renal toxicity over the long term. Tenofovir alafenamide, a new prodrug, now makes it possible to reduce toxicity, but at the cost of an alteration in lipid profile. There is currently no recommendation for follow-up of lipid profile when switching from tenofovir disoproxil fumarate to tenofovir alafenamide. Objective: Our study aimed to evaluate the effects on renal function and lipid profile of a switch from tenofovir disoproxil fumarate to tenofovir alafenamide, and the consequences for patient management. Methods: Demographic, clinical and biological data was recorded from a retrospective clinical cohort study in real-life, including patients who switched from tenofovir disoproxil fumarate to tenofovir alafenamide. A descriptive analysis of the study population, with a comparison of biological parameters using the paired Student t test for paired data was performed. Results: From January 2016 to January 2019, a total of 103 patients were included. There was no significant difference in renal function before vs after the switch in therapy (p=0.29 for creatinine, p=0.30 for phosphoremia). We observed a change in lipid profile, with a significant increase in total cholesterol (p=0.0006), HDL cholesterol (p=0.0055) and triglycerides (p=0.0242). Four patients received lipid-lowering therapy after switching. Conclusion: In patients who switch from tenofovir disoproxil fumarate to tenofovir alafenamide, lipid profile is altered, and may require initiation of lipid-lowering therapy. It seems necessary to monitor lipid parameters after this switch, despite the absence of an official recommendation.

Background: The impact of pharmacokinetic variability of cabotegravir (CAB) and rilpivirine (RPV) long-acting (LA) injectable therapy on virological outcomes remains controversial. This study aimed to characterize the variability of CAB and RPV trough concentrations (Ctrough) and to identify the predictors of suboptimal exposure and virologic failure (VF) in a large real-world cohort. Methods: We conducted a multicenter observational study including people with human immunodeficiency virus type 1 (HIV-1) initiating LA-CAB/RPV as maintenance therapy from January to December 2022, in whom CAB and RPV plasma Ctrough were determined as part of therapeutic drug monitoring (TDM). Results: A total of 1674 CAB and 1687 RPV Ctrough measurements were collected from 736 people with HIV-1 (PWH). Significant interindividual variability in concentrations was observed. At month 1/month 3, 20%–30% of PWH had Ctrough <1120 ng/mL for CAB and 32 ng/mL for RPV. Predictors of lower Ctrough were body mass index (BMI) ≥30 kg/m2 and female sex at month 1, and only male sex at steady state. After a median follow-up of 12 (interquartile range, 9–16) months, VF occurred in 2.5% of PWH. At month 6 and month 12, VF was significantly associated with the presence of at least 2 risk factors (obesity, suboptimal Ctrough) (odds ratio [OR], 4.6, P = .047; OR, 5.15, P = .014), and CD4 nadir (OR, 0.56, P = .008; OR, 0.5, P = .001). Conclusions: Our large real-world study confirms significant variability in CAB and RPV exposure, with BMI and sex as key predictors of lower Ctrough. Suboptimal CAB and RPV Ctrough, particularly in people with obesity, increases the risk of VF during the first year of treatment, highlighting the usefulness of TDM in clinical practice.