A Rare and Deadly Cancer May Have an Unexpected New Vulnerability

Key Points:

• A Vermont research team developed an experimental drug, RSO-021, targeting the mitochondrial enzyme PRX3 to control mesothelioma, achieving disease control in 67% of patients in a phase one clinical trial.
• The drug works by blocking PRX3, causing harmful reactive oxygen species to accumulate in cancer cells, leading to tumor cell death while sparing healthy cells, a novel approach that reverses prior assumptions about antioxidants in cancer treatment.
• The phase one trial showed the treatment was well tolerated, extended patient survival beyond standard therapies, and demonstrated on-target engagement in tumors, with patients averaging 4.2 months without disease progression.
• Researchers are advancing to phase two trials and developing second-generation PRX3 inhibitors with improved solubility for potential oral administration, aiming to expand the therapy to other cancers beyond mesothelioma.
• The study highlights a promising new therapeutic strategy with both cytotoxic and immunomodulatory effects, potentially transforming treatment options for mesothelioma and other aggressive tumors with significant unmet medical needs.