Mesothelioma drug thiostrepton controls disease in 67% of trial patients

September 17, 2026 at 10:16 AM2 min

This digest was compiled by AI from multiple sources — links to the originals are below.

An experimental drug controlled mesothelioma progression in 67% of patients in a phase one trial sponsored by RS Oncology. The drug, thiostrepton, disables the antioxidant enzyme PRX3, causing oxidative stress that kills tumor cells. Mesothelioma, linked to asbestos exposure, affects about 30,000 people annually with a median survival of 12 months.

Key Facts

About 30,000 people worldwide are diagnosed with mesothelioma every year.
In a phase one clinical trial, the experimental drug controlled disease progression in 67% of participants with relapsed mesothelioma.
The drug thiostrepton blocks the antioxidant enzyme PRX3, causing hydrogen peroxide to accumulate in tumor cell mitochondria and trigger cell death.
Mesothelioma patients have a median survival of about 12 months and a five-year survival rate of approximately 10%.

Disease Burden

Mesothelioma is a rare and aggressive cancer most often linked to asbestos exposure. Inhaled asbestos fibers can become trapped in the lungs, triggering chronic inflammation that may lead to cancer decades later. About 30,000 people worldwide are diagnosed with mesothelioma every year. Many patients are men who previously worked in shipbuilding, oil refining, or asbestos manufacturing. Median survival is about 12 months, and the five-year survival rate is approximately 10%.

Trial Results

A phase one clinical trial sponsored by RS Oncology, LLC tested the experimental drug in patients with relapsed mesothelioma. The drug controlled disease progression in 67% of participants. Tumors shrank in some patients, and the drug was generally well tolerated. Critically ill patients in the trial lived longer than patients receiving standard treatments.

Mechanism of Action

Mesothelioma cells produce unusually high levels of reactive oxygen species due to highly active metabolisms. To survive oxidative stress, cancer cells increase production of the antioxidant enzyme peroxiredoxin 3, or PRX3, inside mitochondria. The experimental drug thiostrepton, a naturally occurring antibiotic, disables PRX3. Blocking PRX3 causes hydrogen peroxide to accumulate inside tumor cell mitochondria, eventually triggering cell death.