Tear Biomarkers of Topical Sirolimus in Meibomian Gland Dysfunction: A Randomized Trial

Purpose: Pharmacodynamic biomarkers of sirolimus were investigated using omics analysis of tear fluids from Japanese patients with meibomian gland dysfunction (MGD). Methods: In a Phase 2a trial, sirolimus or vehicle eyedrops were administered twice daily for 12 weeks. Tear samples from 29 patients (15 sirolimus, 14 vehicle) were collected pre- and post-treatment. LC-MS/MS-based proteomics and lipidomics were performed. Within-group changes were analyzed, followed by differential expression and pathway analysis. Key candidates were evaluated using estimation plots (Registration ID: UMIN000049186). Results: Over 3000 proteins and 55 lipids were quantified. mTOR signaling components (ATP6V1D, RRAGC, DEPTOR) were significantly modulated. ATP6V1D showed a significant decrease in the sirolimus group (p = 0.0024), but not in the vehicle group (p = 0.528). Lipids 12-HETE and 13-HpODE significantly increased post-treatment in the sirolimus group. Conclusion: Results suggested that sirolimus inhibited the mTOR pathway. ATP6V1D, 12-HETE, and 13-HpODE were suggested to be pharmacodynamic biomarkers for sirolimus. These findings may facilitate pharmacodynamic monitoring of mTOR-targeted therapies for ocular surface disorders. Keywords: MGD, pharmacodynamic biomarker, tear fluid sample, mTOR inhibitor