Dry eye disease is often managed with tear substitutes that do not fully restore ocular surface homeostasis because they cannot interact with the ocular surface epithelium or modulate inflammation. This pilot study evaluated the efficacy of ST-Lysyal, an ocular surface modulator, compared with hyaluronic acid eye drops in patients with dry eye.
ST-Lysyal (T-Lys) has shown “the ability to restore the corneal epithelial cell damage in an in vitro model of DED [dry eye disease], as well as the modulation of the inflammatory process” in previous research, Stefano Barabino, MD, PhD, of the Ocular Surface and Dry Eye Center at Milan University and colleagues described in their recent Ophthalmology and Therapy article. Their study aimed to extend preclinical evidence of T-Lys’s efficacy to clinical practice and provide an overview of any effects of the medication, as evidenced by the existing literature.
This double-masked, randomized trial was conducted at the Ocular Surface and Dry Eye Center, University of Milan with 27 patients diagnosed with DED and met the symptom severity criteria. Patients had a mean age of 67 years old.
Patients were split into a treatment group and a control group. In the treatment group, they received T-Lys eye drops 3 times daily for 2 months. The control group received 0.2% hyaluronic acid (HA) combined with tamarind seed polysaccharide (Xiloial Zero®). Outcomes focused on symptom severity according to Symptom Assessment in Dry Eye (SANDE) scores, tear film breakup time (T-BUT), and corneal and conjunctival staining.
The T-Lys group showed significant improvement in symptom severity reduction from 4.58 ± 2.57 mm at baseline to 2.92 ± 1.38 mm at two months. T-BUT increased from 2.58 ± 1.31 seconds to 3.58 ± 1.37 seconds, and corneal staining decreased from 2.16 ± 4.17 to 1.41 ± 3.70.
Patients in the control group showed no significant improvement in symptom severity (5.13 ± 2.29 mm to 5.3 ± 2.4 mm), T-BUT (3.07 ± 1.43 seconds to 3 ± 1.13 seconds), or corneal staining.
Neither group showed significant improvements in conjunctival staining, and no adverse events were reported.
The researchers wrote of T-Lys’s effects on the ocular surface: “A possible explanation of this effect could be related to the particular conformation of T-Lys, which is more resistant to the lytic enzyme hyaluronidase than HA because of the presence of lysine hyaluronate and thymine at the target sites of the enzyme. Moreover, T-Lys can attract and move water, and is able to modify the cell’s environment through the expression of growth factors and inflammatory mediators.”
They further described and speculated on T-Lys’s mechanism of action, and suggested that larger studies with "additional measures, such as measuring the exact quantity of markers of inflammation on ocular surface epithelial cells, will be useful to confirm the obtained results and possibly to investigate the efficacy of T-Lys in other ocular surface diseases.”
A full list of author disclosures can be found in the published research.
