UVM-linked trial reports disease control in 67% of relapsed mesothelioma patients

A University of Vermont team and collaborators described in Nature Communications a strategy that targets the mitochondrial antioxidant enzyme peroxiredoxin 3, or PRX3, in mesothelioma, SciTechDaily reported, citing the journal study and a related phase one clinical trial. Mesothelioma is rare but aggressive, affecting about 30,000 people worldwide each year, with typical survival of about 12 months after diagnosis and only around 10 percent alive five years later, according to the report. Immunotherapy and chemotherapy offer limited benefit for many patients. In a phase one trial sponsored by RS Oncology, patients with relapsed mesothelioma received an experimental drug that stopped disease progression in 67% of participants, with some tumor shrinkage. The treatment was generally well tolerated, and overall survival among the 15 participants exceeded what is generally observed with current therapies, the report said, while average progression-free time was 4.2 months. The approach blocks PRX3 so reactive oxygen species accumulate inside tumor mitochondria until cells die, reversing a long-standing focus on adding antioxidants. RS Oncology reformulated the natural antibiotic thiostrepton into RSO-021, delivered into the chest through a catheter used for pleural effusions. At 90 milligrams, the UK MHRA-supervised trial met safety and tolerability goals, with no deaths attributed to treatment, and tissue samples confirmed on-target engagement. Lab work showed removing PRX3 slowed mesothelioma cell division and blocked tumor formation in animals, while other research found healthy mice lacking PRX3 developed without harmful effects, SciTechDaily reported. Brian Cunniff of UVM and research scientist Victoria Gibson are among the authors; the paper DOI is 10.1038/s41467-026-75153-y.