On February 1, 2024, a team of researchers investigating the new anti-cancer drug RSO-021 announced they’ve successfully dosed the first patient in phase 2 of a clinical trial that includes individuals diagnosed with pleural mesothelioma.

RSO-021, developed by clinical biotech company RS Oncology, showed promise in phase 1 of the clinical trial, suggesting it could eventually become another mesothelioma treatment option for patients. The medication works differently than other mesothelioma drugs by pumping the brakes on the cell growth process, eventually leading to tumor cell death.

“RSO-021 is an exciting novel anti-cancer treatment that can potentially help a global population of cancer patients who are left with little to no options. Commencing the phase 2 portion of our trial presents a major milestone for patients and their caregivers.”

- Jarrett Duncan, CEO of RS Oncology

RSO-021 is just one example of new targeted therapies for mesothelioma that offer hope to patients with limited treatment options.

Mesothelioma Hope talked with Dr. Brian Cuniff, Chief Science Officer at RS Oncology, about the trial’s initial findings and what could be next for mesothelioma treatment.

How RSO-021 Affects Mesothelioma

Cuniff told Mesothelioma Hope that mesothelioma cells require increased energy to grow. The experimental drug RSO-021 aims to slow that energy exponentially.

“A normal cell is like a car driving at 65 mph, but a cancer cell is a car driving at 120 mph. The operation of the car at that speed requires the engine to be operating perfectly,” explained Cuniff. “This new drug is like sticking a potato in the tailpipe of the cancer cell. RSO-021 binds to the PRX3 enzyme that keeps the cell functioning properly and disables it.”

Dr. Sean Dulloo, one of the trial’s researchers, highlighted three trial participants.

Each patient was diagnosed with pleural mesothelioma and responded favorably to the new mesothelioma treatment.

All three patients experienced reduced fluid build-up in the lining of the lungs (pleural effusion) as well as a reduction in the size of their tumors.

In fact, fluid was completely stopped from draining into the lung lining for two patients and was significantly decreased for the third.

“Essentially we have a drug that is reducing pleural effusion as well as treating the cancer,” said Dulloo in his presentation.

The new mesothelioma treatment RSO-021 works differently than immunotherapy and chemotherapy drugs because it directly targets the enzymes on cancerous cells without the risk of damaging healthy cells in the process.

“This therapy was specifically researched and developed for mesothelioma to give patients another option for treatment. No other mesothelioma drug works like this,” said Cuniff.

If you or a loved one has been diagnosed with mesothelioma, you can learn more about symptoms and the latest treatments in our Free Mesothelioma Guide.

Investing in New Mesothelioma Treatment

Mesothelioma is a rare and aggressive form of cancer caused by exposure to asbestos. Tiny thread-like asbestos fibers can be inhaled and remain in the lungs for decades before causing cancerous tumors to form.

Did You Know?

People who are most at risk of developing mesothelioma include veterans and trade workers due to the widespread use of asbestos in shipbuilding, construction, and other industries from the 1930s to the early 1980s.

“Even though mesothelioma is rare, there are some incredible scientists and doctors who are passionate about studying this disease. They are very invested in finding new therapies,” said Cuniff. “It can be frustrating for patients who run out of options. We’re working to bring as many options as possible to improve patient outcomes and quality of life.”

Since the first phase of the study ended in September 2023, Cuniff and the rest of his UK-based research team have worked tirelessly to prepare for continued phases of the clinical trial, which will eventually begin enrolling patients in the United States.

The team plans to present detailed trial results at the American Society of Clinical Oncology (ASCO) Conference in August 2024. Researchers hope the new drug RSO-021 could join other emerging treatments that have been approved for mesothelioma in recent years.

Our team can help you find the latest mesothelioma treatments and help you enroll in clinical trials. Call us today at (866) 608-8933 to get started.

Get Help Finding Mesothelioma Treatment Near You

Mesothelioma is a devastating cancer that affects thousands of families every year. Mesothelioma Hope is dedicated to helping those impacted by this disease find the treatment and support they need.

If you or a loved one has been diagnosed with mesothelioma, our Patient Advocates can connect you with cancer centers, specialized doctors, and clinical trials for new mesothelioma treatments that may help you live longer.

Start your treatment journey today with our Free Doctor Match program.

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beth swantekWritten by:

Contributing Author at Mesothelioma Hope

Beth Swantek has been writing about the dangers of asbestos since 2013. Beth served as a media professional for over 30 years and began her career as a broadcast journalist. After her daughter suffered a traumatic brain injury at birth, Beth has devoted her life to helping men and women experiencing deep loss — such as those living with mesothelioma.

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  1. Business Wire. (2023). RS Oncology Announces Completion of First-in-Human Phase 1 Clinical Trial of RSO-021, a Novel Irreversible Inhibitor of Mitochondrial PRX3. Retrieved February 5, 2024, from https://www.businesswire.com/news/home/20230911181395/en/RS-Oncology-Announces-Completion-of-First-in-Human-Phase-1-Clinical-Trial-of-RSO-021-a-Novel-Irreversible-Inhibitor-of-Mitochondrial-PRX3
  2. Business Wire. (2024). RS Oncology Announces First Patient Dosed in Phase 2 Clinical Study (MITOPE) Investigating RSO-021 for the Treatment of Malignant Pleural Mesothelioma and Metastatic Disease to the Lung. Retrieved February 5, 2024, from https://www.businesswire.com/news/home/20240201668709/en/ 
  3. R/S Oncology Symposium. International Mesothelioma Interest Group Conference. (Lille, France, 2023). Retrieved February 5, 2024, from https://www.businesswire.com/news/home/20230803096425/en/RS-Oncology-presents-new-drug-[…]ical-development-for-Mesothelioma-and-lung-cancer-patients

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