Switching from abacavir to tenofovir disoproxil fumarate is associated with rises in soluble glycoprotein VI, suggesting changes in platelet-collagen interactions.
OBJECTIVES: Altered platelet function has been proposed as an underlying mechanism to explain increased risk of myocardial infarction in people living with HIV associated with use of the nucleoside reverse transcriptase inhibitor abacavir (ABC). We aimed to examine changes in platelet biomarkers in people living with HIV switching from ABC.
METHODS: In a prospective, 48-week substudy of virally suppressed HIV-1-positive subjects randomized to remain on ABC/lamivudine (ABC/3TC) or switch to tenofovir disoproxil fumarate/emtricitabine, we measured soluble glycoprotein VI (sGPVI), soluble P-selectin, soluble CD40 ligand and von Willebrand factor in plasma collected over time and assessed differences using mixed effect models.
RESULTS: Of 312 randomized participants, 310 were included in the analysis. Mean (SD) age 46.4 (9.3) years, 262 (85%) men and 201 (65%) white. At baseline, there was no significant between-group difference in sGPVI [tenofovir disoproxil fumarate/emtricitabine 3.75 (0.25) versus ABC/3TC 3.61 (0.22) ng/ml, P = 0.69]. Greater increases in sGPVI from baseline to week 48 occurred in those switched from ABC/3TC (effect size +0.57 ng/ml; 95% confidence interval, 0.2-0.94; P = 0.003). There was no significant baseline difference or change overtime in soluble P-selectin, soluble CD40 ligand or von Willebrand factor between groups.
CONCLUSION: The significant increases in sGPVI that occur with a switch from ABC/3TC are suggestive of changes in platelet function centred on platelet/collagen interactions and potentially represent an underlying mechanism to explain increased risk of myocardial infarction with ABC.