New Treatment for Malignant Mesothelioma Kills Cancer ‘From the Inside Out’

The University of Vermont is about to start a first-in-human trial of a new kind of treatment for malignant mesothelioma. 

The new approach involves a drug called RSO-021. The drug works differently from other cancer therapies. It blocks the ability of cancer cells to manage their own waste products. It’s developers say the new treatment for malignant mesothelioma aims to kill cancer cells from the inside out. 

The concept for RSO-021 was first developed at the University of Vermont. Scientists at Wake Forest University School of Medicine and the UK biotech company RS Oncology have tested the drug in mice with promising results. 

Human trials of RSO-021 will start soon in the UK. US patients will be recruited in 2022. 

Alternative Mesothelioma Therapies Urgently Needed

Mesothelioma is an aggressive cancer with no known cure. It is usually caused by prolonged exposure to asbestos. It can take decades for an exposed patient to develop mesothelioma but once symptoms appear, the patient may have only months to live. 

Doctors urgently need a new treatment for malignant mesothelioma. The current approved therapies – including chemotherapy, immunotherapy, and an electrical device called TTFields – only slow down this fast-growing malignancy. 

The University of Vermont researcher who helped develop RSO-021 says mesothelioma patients may not be the only patients to benefit from the new approach.

“All tumor cells are very reliant on efficient waste management systems to grow and survive; we were interfering with that,” explains Brian Cunniff PhD, who helped pioneer the process. 

Cells ‘Choke on Exhaust’ with the New Treatment for Malignant Mesothelioma

All cells produce byproducts of metabolism. Cancer cells produce even more of these byproducts than healthy cells do and they produce them faster. Normally, cells have clean-up processes for getting rid of these toxins. RSO-021 blocks these processes. The result is a build-up of toxins that is not sustainable. 

“The drug takes away the ability of cells to metabolize toxic byproducts, so they essentially choke on their own exhaust,” says Dr. Cunniff. Dr. Cunniff helped develop the concept while he was still working on his PhD. Now, his laboratory at the University of Vermont Cancer Center will process the data for the first human trials of RSO-021.

The goal of the Phase 1 human trials will be to test the safety and activity of the new treatment for malignant mesothelioma. Animal tests of the approach look good but more data is needed.

“Until we have sufficient data from the phase 1 clinical trial, it will be difficult to fully understand the possibilities of this approach, although there is considerable optimism,” says Dr. Cunniff. 

If the Phase 1 trials confirm that RSO-021 is a possible new treatment for malignant mesothelioma, Phase 2 will help doctors determine the ideal dosage. 

About 3,000 people in the US develop mesothelioma every year. The rate of new cases is even higher in many developing countries where there are few restrictions on asbestos. 

Source:

Strotmeyer, K, “UVM Cancer Center Research Leads to First-of-Its-Kind Clinical Trial of Mesothelioma Treatment”, October 26, 2021, University of Vermont Larner College of Medicine news release, http://www.med.uvm.edu/home/2021/10/26/uvm_cunniff_lab