Mesoglycan Shows Long-Term Promise After Superficial Vein Thrombosis

Mesoglycan may help reduce the long-term recurrence of superficial vein thrombosis (SVT) following standard anticoagulant treatment, according to findings from the METRO trial. Although the therapy did not significantly improve outcomes during the first year of treatment, researchers observed fewer recurrent SVT events two years after enrolment.

Superficial vein thrombosis, once considered a relatively benign condition, is now recognised as being associated with an increased risk of deep vein thrombosis (DVT) and pulmonary embolism. However, evidence guiding long-term secondary prevention after an initial SVT episode remains limited, leaving uncertainty over how best to reduce recurrent disease.

Trial Evaluated Long-Term Prevention Strategy

The multicentre, double-blind, placebo-controlled phase II trial enrolled 553 adults with lower-limb SVT across 16 centres in Italy.

After completing the recommended 45-day course of fondaparinux, participants were randomly assigned to receive either oral mesoglycan (50 mg twice daily) or placebo for 12 months. Patients were then followed for an additional 12 months to assess whether treatment influenced longer-term outcomes.

The primary efficacy endpoint included recurrent or extending SVT, new deep vein thrombosis, pulmonary embolism, or fatal pulmonary embolism.

No Significant Benefit During Treatment

At the end of the 12-month treatment period, there was no statistically significant difference between the mesoglycan and placebo groups.

Composite efficacy events occurred in 21.8% of patients receiving mesoglycan compared with 24.5% of those receiving placebo. The difference did not reach statistical significance, indicating that mesoglycan did not reduce recurrent venous thromboembolic events during active treatment.

Fewer Recurrences Observed After Two Years

By 24 months, however, outcomes favoured mesoglycan.

The cumulative incidence of efficacy events was 30.6% in the mesoglycan group compared with 42.5% among patients receiving placebo. Researchers reported that this difference was driven entirely by a reduction in recurrent superficial vein thrombosis rather than differences in deep vein thrombosis or pulmonary embolism.

Notably, recurrent SVT occurred in 39% of patients receiving placebo over the two-year follow-up period, suggesting recurrence may be more common than previously recognised.

No Major Bleeding Reported

Importantly, no major or clinically relevant non-major bleeding events were reported in either treatment group during the study.

Mesoglycan is thought to exert mild antithrombotic effects while helping restore the endothelial glycocalyx, potentially supporting vascular repair without substantially increasing bleeding risk.

Larger Trials Required

The authors conclude that mesoglycan cannot currently be recommended as an effective strategy for preventing recurrent venous thromboembolism during the first year after SVT. However, the reduction in recurrent SVT observed after two years suggests the drug may offer longer-term benefits that warrant further investigation.

The researchers caution that the study recruited fewer participants than originally planned because of disruption caused by the COVID-19 pandemic, which limited statistical power. They also note that recurrence rates in the placebo group were higher than expected, meaning the findings should be interpreted carefully.

Further large-scale clinical trials will be needed to confirm whether mesoglycan can play a role in the long-term secondary prevention of superficial vein thrombosis.