Theralase Technologies has announced impressive interim clinical data from its Phase II trial of light-activated Ruvidar (TLD-1433) for the treatment of BCG-Unresponsive Non-Muscle Invasive Bladder Cancer (NMIBC) Carcinoma In-Situ (CIS). The data, presented at both the Canadian Bladder Cancer Forum 2025 and the American Urological Association 2025 Annual Meeting, demonstrates significant efficacy and safety profiles that could potentially transform treatment options for bladder cancer patients who have exhausted standard therapies.
Clinical Trial Results Show Strong Efficacy and Safety
The interim analysis includes data from 79 enrolled and treated patients, with 64 patients having completed the study or been removed according to protocol. For the primary endpoint, 62.5% (40/64) of patients demonstrated a Complete Response (CR), defined as negative cystoscopy and negative urine cytology at any point in time. When including patients with Indeterminate Response (negative cystoscopy but positive or suspicious urine cytology), the total response rate increases to 68.8% (44/64).
Notably, the therapy shows impressive durability of response. Among patients who achieved a CR, 45.0% (18/40) maintained their cancer-free status for at least 12 months, while 25.0% (10/40) continued to show a CR at 24 months, and 20.0% (8/40) at 36 months. Perhaps most remarkably, one patient from the Phase Ib NMIBC clinical study has demonstrated a sustained CR lasting over 7 years after just a single treatment.
The safety profile appears robust, with 100% (64/64) of patients experiencing no Serious Adverse Events (SAEs) directly related to the Study Drug or Study Device. While 15 SAEs were reported across all 79 treated patients, Theralase believes these were unrelated to the treatment.
Mechanism of Action and Therapeutic Potential
Dr. Arkady Mandel, Chief Scientific Officer at Theralase, explained the mechanism behind Ruvidar's effectiveness: "What we have learned in our research is that Theralase's light-activated small molecule, Ruvidar, is able to destroy cancer through the production of reactive oxygen species and stimulation of the immune system by blocking multiple immune checkpoints."
The therapy works by blocking CD47 (a macrophage checkpoint signal on cancer cells), PD-L1 (a protein that prevents T cells from attacking cancer cells), and reducing deubiquitinating enzymes, which have been linked to numerous cancers.
Development Timeline and Future Applications
Theralase expects to complete enrollment in the Phase II trial by mid-2025, with plans to report on 75 patients who have completed the study by December 2025 and all 90 patients by September 2026. The company intends to submit a New Drug Application to Health Canada and the FDA in Q4 2026, with potential regulatory decisions by Q1 2027.
Beyond bladder cancer, Theralase is advancing Ruvidar for multiple additional indications:
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Glioblastoma Multiforme (GBM): Pre-clinical research has been completed, with GLP toxicology studies expected to conclude in Q4 2025, allowing for a Phase I/II adaptive clinical study to begin in Q1 2026.
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Non-Small Cell Lung Cancer (NSCLC): Pre-clinical studies have shown that mice treated with x-ray activated Rutherrin (IV formulation of Ruvidar) demonstrated up to 4-fold slower tumor progression compared to radiation alone.
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Muscle Invasive Bladder Cancer (MIBC): Pre-clinical research is underway to develop Ruvidar as an intravenous treatment, with clinical studies potentially beginning in Q1 2026.
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Blood Cancers: Research is ongoing to develop Ruvidar for leukemia, lymphoma, and myeloma as an extracorporeal treatment.
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Herpes Simplex Virus (HSV-1): The company is developing a topical formulation of Ruvidar for cold sore lesions, with clinical studies potentially starting in Q1 2026.
Addressing an Unmet Medical Need
Carcinoma In-Situ of the bladder represents an aggressive form of NMIBC, accounting for about 10% of all bladder cancer cases. While intravesical BCG is the standard first-line treatment, high rates of BCG failure highlight the need for additional therapies. CIS in the bladder is associated with a less favorable prognosis and greater risk of progression to Muscle Invasive Bladder Cancer.
"Management of BCG-Unresponsive NMIBC CIS is and remains an unmet need," noted Dr. Mandel. "Pending regulatory approval, the latest clinical data presented supports the use of light-activated Ruvidar by the urology community to safely and effectively treat patients inflicted with BCG-Unresponsive NMIBC CIS, helping to revolutionize the treatment landscape for bladder cancer."
Corporate Strategy and Future Outlook
As Theralase completes enrollment in the Phase II trial, the company is actively seeking commercialization partners for international marketing and sales of Ruvidar. Discussions are underway with international pharmaceutical companies regarding licensing of light-activated Ruvidar for BCG-Unresponsive NMIBC CIS, collaborative research on NMIBC treatment, and combining Ruvidar with other FDA-approved drugs.
The company has raised CAD 6.3 million over the last two years to support its research and development programs and is investigating potential US listing opportunities to enhance access to capital markets.
Roger DuMoulin-White, President and CEO of Theralase, expressed optimism about the company's pipeline: "As Theralase wraps up the Phase II NMIBC clinical study in 2025 with a Health Canada and FDA regulatory submission planned in late 2026, I look forward to working with our world-class scientists, researchers and medical doctors in the commencement of numerous new clinical studies, focused on hard to treat viral infections and some of the deadliest and most difficult to treat cancers in the world."
