Pleural mesothelioma, which affects the lining of the lungs, is the most common type of mesothelioma, an aggressive cancer caused by asbestos exposure.

Because mesothelioma is commonly misdiagnosed, it’s often not found until it is in the advanced stages. As a result, people with pleural mesothelioma tend to have a poor prognosis (expected health outcome) with low survival rates.

A phase I clinical trial exploring a unique combination of a targeted vaccine and immunotherapy revealed promising results for advanced-stage pleural mesothelioma. The trial, led by biopharmaceutical company SELLAS Life Sciences Group, tested the ability of galinpepimut-S (GPS) and Opdivo® to trigger an immune response in pleural mesothelioma patients.

Patients who had an immune response to GPS lived 3 times longer — 27.8 months vs. 9 months — than those who didn’t. What’s so notable about this is each of these patients’ cancer was not responding to treatment or had come back after other treatments.

Read more about the study results and how Mesothelioma Hope can help you find pleural mesothelioma clinical trials in your area.

What Immunotherapy Drugs Were Tested?

The clinical trial tested two immunotherapy drugs: galinpepimut-S and nivolumab (Opdivo).

Learn more about each medication and how they work below.

Galinpepimut-S (GPS)

Galinpepimut-S (GPS) is a protein-based cancer vaccine that activates the Wilms Tumor 1 (WT1) antigen to prevent tumors from developing.

When administered, GPS supports WT1 cells and other immune cells so they can recognize and destroy cancer cells. The drug can also help the immune system remember how to attack cancer cells so it can continue fighting mesothelioma after treatment.

According to SELLAS, GPS has the potential to increase mesothelioma survival rates by preventing or delaying cancer recurrence in patients with little to no signs of disease.

Nivolumab (Opdivo®)

Nivolumab, sold under the brand name Opdivo®, is an immune checkpoint inhibitor, and one of the first immunotherapy drugs approved for pleural mesothelioma treatment.

It works by stopping a certain protein known as PD-1 from allowing mesothelioma to go undetected by the immune system. By halting this protein, T-cells can target and fight cancerous cells.

Find a mesothelioma specialist near you with our Free Doctor Match program to help you access the latest treatments, like Opdivo and other immunotherapies.

How Did the Mesothelioma Clinical Trial Work?

This mesothelioma clinical trial involved 10 patients, 9 of whom received at least 3 doses of GPS, with the third GPS dose given along with nivolumab. Researchers were curious if the immune response measured by certain protein levels could indicate positive treatment results.

To measure each patient’s immune response, samples were gathered from 90% of the patients to analyze their immune response to GPS.

Clinical Trial Results: An Increased Overall Survival Rate for All Patients

Overall, the clinical trial results showed improved mesothelioma life expectancy for all patients who received this new immunotherapy combination.

The following results were observed:

  • The 9 out of 10 patients who received a combination of GPS and Opdivo experienced the most positive results with 17.6 months median overall survival (OS).
  • Patients with stage IV mesothelioma had a median survival of 14.6 months, more than 2.5 months longer than the typical life expectancy for this stage.
  • The median OS for patients who lacked an immune response to GPS was 9 months. However, the median OS for patients with an immune response to GPS was 27.8 months, which was over 3 times longer than those who lacked an immune response to GPS.
  • All patients experienced 11.9 weeks median progression-free survival, which occurs when the cancer is not spreading.

These results are incredibly positive for pleural mesothelioma patients looking for additional treatment options like immunotherapy. It also suggests that a strong immune response is correlated with significant survival benefits in patients when given with checkpoint inhibitors.

“We have observed yet again strong GPS-specific immune responses which appear to be correlated with significant survival benefit in patients when combined with checkpoint inhibitors, a more than 200% survival benefit.”

- Angelos Stergiou, CEO and president of GPS manufacturer SELLAS Life Sciences Group

Stergiou and SELLAS believe these survival benefits suggest the ability of GPS to stop the progression of aggressive cancers like pleural mesothelioma.

In the future, researchers may use this study’s findings to probe deeper into GPS’s abilities to fight cancer and increase patients’ quality of life and mesothelioma life expectancy.

Find Pleural Mesothelioma Clinical Trials With Our Help

Clinical trials for mesothelioma are constantly looking for new approaches to this aggressive cancer and need patients to help them test these treatments.

Mesothelioma Hope can help you find clinical trials near you so you can get access to emerging therapies like GPS. Our Patient Advocates can also connect you with mesothelioma specialists who have experience administering the latest treatments.

Contact us now at (866) 608-8933 or get started with our Free Doctor Match program.

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Laura WrightWritten by:

Lead Editor

Laura Wright is a journalist and content strategist with more than 15 years of professional experience. She attended college at the University of Florida, graduating magna cum laude with a bachelor’s degree in journalism in 2008. Her writing has been featured in The Gainesville Sun and other regional publications throughout Florida.

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  1. BioSpace. (December 2023). SELLAS Life Sciences Reports Positive Follow-Up Immune Response and Survival Data in Completed Phase 1 Study of Galinpepimut-S Combined with Opdivo® in Advanced Malignant Pleural Mesothelioma. Retrieved January 24, 2024, from
  2. National Cancer Institute. (2022, April 7). Immune Checkpoint Inhibitors. Retrieved January 24, 2024, from
  3. National Cancer Institute. (2023, December 6). Nivolumab. Retrieved January 24, 2024, from
  4. SELLAS Life Sciences Group. (n.d.). GALINPEPIMUT-S (GPS) THERAPY. Retrieved January 24, 2024, from

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