Ractigen’s small activating RNA (saRNA) therapy, RAG-01, designed to treat non-muscle invasive bladder cancer (NMIBC) has shown early promise in a Phase I trial.
Data presented at the European Association of Urology (EAU 2025) urology conference highlighted a 66.7% complete response rate in patients with carcinoma in situ (CIS) after treatment with RAG-01, particularly in those who had failed Bacillus Calmette-Guérin (BCG) therapy.
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The therapy, which targets the p21 tumor suppressor gene, demonstrated a favourable safety profile with no dose-limiting toxicities. Further clinical development is planned to assess safety and efficacy at higher doses.
Results from the company’s Phase I trial (NCT06351904) also found that 66.7% of patients with papillary tumours remained disease-free at the 3-month assessment point. Both positive results were observed in the two lowest dose cohorts in the trial.
The Chinese company’s saRNA therapy is intended to increase expression in the p21 tumour suppressor gene and acts as a cyclin-dependent kinase inhibitor (CDKI). Through this, p21 typically works to halt the cell cycle at specific checkpoints, allowing for DNA repair or preventing cells with damaged DNA from progressing.
The ongoing open-label trial has so far recruited 15 people from three sites across Australia. The trial involves doses of RAG-01 into the bladder via intravesical instillation, with patients randomised to receive either 30 mg, 100 mg, 300 mg or 600 mg respectively.
Trial investigator and clinician at the Royal Hospital Melbourne, Paul Anderson, said: “The striking CR rates observed in these early cohorts are highly encouraging, particularly for BCG-unresponsive NMIBC patients who currently have limited treatment options. These results pave the way for further exploration of RAG-01’s capabilities in this challenging disease.”
NMIBC is a form of cancer that affects the inner lining of the bladder but has yet to spread to any other part of the body. Research by the Mayo Clinic estimates that approximately 75% to 80% of newly diagnosed bladder cancers are classified as NMIBC.
GlobalData’s Pharmaceutical Intelligence Centre estimates that there are just 31 currently marketed therapies for NMIBC with Merck’s Keytruda and Mylan’s Doxorubicin taking up the most space in the market. The overall NMIBC market brought in more than $29bn in 2024, expected to climb to $31bn by the end of 2030.
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CEO of Ractigen, Long-Cheng Li, said: “These preliminary findings are incredibly exciting and validate the potential of our saRNA platform to address significant unmet needs in oncology.
“Achieving such a high complete response rate in the lowest dose cohorts, with a favourable safety profile, is a testament to the innovative science behind RAG-01 and its potential to become a transformative therapy for patients with BCG-unresponsive NMIBC.”
Elsewhere in the market for bladder cancer, AstraZeneca has reported positive results from the Phase III NIAGARA trial of Imfinzi alongside neoadjuvant chemotherapy. Meanwhile, Pfizer’s Phase III CREST trial evaluating sasanlimab with Bacillus Calmette-Guérin (BCG) has met its primary endpoint.
