Experimental Drug Showed Promise for Mesothelioma Patients
A small clinical trial tested a new treatment that may help control disease progression for those with mesothelioma.
Updated on Sept. 21, 2026 in Cancer
Live Poll
Do you trust private companies to objectively develop drugs discovered in university laboratories?
In a phase 1 trial conducted between 2022 and 2023, the drug RSO-021 demonstrated a 67% disease control rate at 12 weeks among 15 participants in the United Kingdom. While the findings offer a potential new avenue for patients, the treatment is not yet FDA-approved.
Why it matters
Mesothelioma, which affects approximately 3,000 Americans annually, remains difficult to treat, and this research explores a novel method of disrupting tumor cell survival. The development marks a step toward potential new therapies, though larger studies are still required.
A phase 1 clinical trial of 15 patients in the United Kingdom found that a weekly 90-milligram dose of RSO-021 achieved a 67% disease control rate at 12 weeks. These results are considered preliminary, and no patient deaths were attributed to the drug during the study period.
The players
RS Oncology
A biotechnology company that sponsored the clinical trial and focuses on developing targeted cancer therapies.
University of Vermont
An academic institution that served as the site for the initial research into the drug formulation.
The details
RSO-021 is a clinical formulation of the antibiotic thiostrepton designed to be delivered directly into the chest via a catheter. The drug works by binding to the PRX3 enzyme within mitochondria, which tumor cells rely on to survive high levels of reactive oxygen species. By blocking this enzyme, the drug aims to disrupt the chemical balance necessary for tumor growth.
Timeline
The phase 1 trial was conducted under MHRA oversight from 2022 to 2023.
The principal investigator presented the phase 1 results in 2024.
The research paper was published in July 2026.
Researchers expect to present phase 2 results in 2026.
Health Landscape
This study is part of an ongoing research program focused on the development of PRX3 inhibitors for oncological care. It represents an early exploration of this enzymatic pathway, with future efforts aimed at creating more accessible second-generation treatment options.
Because this drug is not yet approved for public use, patients should rely on established protocols and discuss ongoing clinical trials with their oncology team. It is essential to consult a physician to understand what current FDA-approved options may be appropriate for your specific condition.
The takeaway
While this early trial shows potential for managing tumor growth in mesothelioma, it is currently an experimental approach that requires further validation in larger studies. Patients and caregivers should focus on maintaining communication with specialists regarding the latest clinical research developments.
What happens next
Researchers expect to present the results of their phase 2 study later in 2026.
Further reading
For more information on current treatment landscapes, explore our Cancer section.
Source note: This article includes information reported by Medical Daily.
Live Poll
Do you trust private companies to objectively develop drugs discovered in university laboratories?
