Theralase(R) Discovers Further Mechanism on How Ruvidar(R) Inactivates Herpes Simplex Virus

Executive Summary

• Theralase® Technologies announced the identification of an additional mechanism of action (MOA) by which its antiviral candidate Ruvidar® (TLD‑1433) inactivates Herpes Simplex Virus‑1 (HSV‑1).
• The new MOA involves electrostatic attraction: positively charged Ruvidar® binds to negatively charged HSV‑1, neutralizing the virus surface charge and preventing cell entry.
• In vitro studies showed complete viral destruction at micromolar concentrations (1.3 µM), achieving up to an 8‑log (99.999999 %) reduction in viable virions.

Key Details

• Study Design: Pre‑clinical in‑vitro experiments measuring zeta potential to assess electrostatic binding between Ruvidar® and HSV‑1, followed by viral infectivity assays.
• Electrostatic MOA Evidence:
• Zeta potential measurements demonstrated a significant shift when Ruvidar® was combined with HSV‑1, confirming charge neutralization.
• Figure 2 (binding assay) illustrates the reduction of negative surface charge on HSV‑1 after exposure to Ruvidar®.
• Viral Inactivation Results:
• At 1,300 nM (1.3 µM), Ruvidar® achieved complete HSV‑1 inactivation, delivering up to an 8‑log reduction in viral load (99.999999 % kill).
• Figure 3 displays the dose‑response curve confirming this potency.
• Comparative Efficacy: Prior data (April 10 2025 & September 24 2025) showed Ruvidar® superior to Acyclovir; the new MOA adds a third antiviral pathway.
• Implications for Development:
• The additional MOA supports continued pre‑clinical and planned clinical development of a topical HSV‑1 treatment slated to commence in 2026.
• Enhances the therapeutic rationale for Ruvidar® as a multi‑modal antiviral agent targeting virus entry, replication, and intracellular survival.
• Quotes:
• Pavel Kaspler, PhD (Research Scientist): “This latest preclinical study has demonstrated that Ruvidar® is very effective in inactivating HSV‑1 by binding to the virus and neutralizing its negative charge.”
• Arkady Mandel, MD, PhD, DSc (Chief Scientific Officer): Emphasized the significance of the new MOA for billions affected by viral infections.
• Roger DuMoulin‑White, B.Sc., P.Eng. (President & CEO): “Preclinical and clinical development for a topical HSV‑1 treatment is slated to commence in 2026.”

Notable Quotes

“Theralase®'s latest research offers valuable new insight into how Ruvidar® can help fight viral infections… we can now add to this list that Ruvidar® is able to bind to negatively charged components in the virus, preventing entry and replication.” – Arkady Mandel, MD, PhD, DSc

Materiality Assessment: Material – Positive (new scientifically substantiated MOA that materially advances the therapeutic profile of a lead product).