Phase-one mesothelioma study reports PRX3 inhibitor results

Researchers at the University of Vermont and collaborators reported phase-one results for RSO-021, a clinical formulation of thiostrepton, in relapsed mesothelioma. In 15 patients, the trial controlled disease progression in 67%; average progression-free survival was 4.2 months, roughly comparable with existing treatments. The treatment blocks PRX3, causing hydrogen peroxide to build up in tumor-cell mitochondria. The phase-one trial was conducted in the UK between 2022 and 2023, and phase two has since been completed; results are expected to be presented this year.