The Potential of Immunotherapy for Mesothelioma

Treatment // June 1, 2017

The immune system is often described as one of our greatest survival tools. It’s vital to fighting off dangers to our health, and an emerging treatment, immunotherapy, is harnessing its strength to better fight cancer.

Immunotherapy is one of the most exciting areas of cancer research today. It’s already shown promise for a variety of cancers, including mesothelioma. This rare cancer faces many obstacles. It’s caused by asbestos exposure, the effects of which can take 20 – 50 years to be seen. These first symptoms are nonspecific, making it that much harder to diagnose.

Early detection is important in a fight against mesothelioma, but many times it isn’t found until the disease has progressed to a later stage. As such, it’s a notoriously difficult cancer to treat, and patients face a dire prognosis. Immunotherapy has provided some hope in the face of such a difficult cancer journey.

Cancer Immunotherapy Month was created to celebrate the potential of this exciting new treatment, as well as raise awareness in support of clinical trials and its continued development. In observance of this month, we’re highlighting some of the most exciting advancements we’ve seen in immunotherapy for mesothelioma patients.

The Benefit of Keytruda

Immunotherapy works by boosting the immune system in some way. In an active immunotherapy, patients receive a cancer drug that stimulates the immune system to more actively fight cancer cells. With passive treatment, patients receive man-made immune proteins to fight the cancer.

Keytruda is a passive immunotherapy known as a checkpoint inhibitor. This means it’s a targeted therapy designed to block certain cell interactions and ultimately help kill cancer cells. Keytruda blocks signals from specific proteins in the cancer cells that would otherwise trick the immune system that a cancer cell is actually a healthy cell. This allows the T-cells, white blood cells that determine and trigger an immune response, to properly attack the cancer cells.

The drug has so far been approved to treat a variety of cancers including melanoma and non-small cell lung cancer, and has also shown success in treating mesothelioma. Keytruda and immunotherapies are so far only available to mesothelioma patients through clinical trials, but researchers have seen promising results from these studies.

One mesothelioma patient and advocate, Mavis Nye, has been in remission for about a year after receiving immunotherapy infusions for two years. After many chemotherapy treatments were proving ineffective, Mavis was fortunately eligible for a clinical trial testing Keytruda on a variety of cancers. Her tumors continued to shrink throughout the trial, and for now she no longer requires any treatment, just continued follow-up scans.

Though it’s still in a developmental phase, other patients have seen success on the drug, as well. Researchers hope with continued study and improvements, it can prove to be an effective mesothelioma treatment for more patients.

Immunotherapy Before Surgery

So far, the majority of studies around immunotherapy have looked at its effectiveness as a standalone or post-surgical treatment. Last fall, a new mesothelioma clinical trial began at The Baylor College of Medicine, to test its effectiveness prior to surgery for malignant pleural mesothelioma patients. It is one of the first clinical trials to study this approach.

Mesothelioma patients are often prescribed treatment in a multimodal method, meaning combining treatments like chemotherapy, surgery and radiation. These conventional treatments, alone or in combination, are considered the current most effective treatment for mesothelioma. This trial could potentially transform that standard treatment for future patients.

In this clinical trial, researchers are testing two variants of checkpoint inhibitors. Some participants receive one kind of immunotherapy checkpoint inhibitor, and the rest receive a combination of two checkpoint inhibitors before surgery. Before and after surgical removal of any visible tumors, researchers will analyze the tumors’ immune response.

Upon the announcement of the trial, the lead researcher Dr. Bryan Burt explained that data showed a more immunogenic tumor formed in pleural mesothelioma than realized before. He believed through further study and development, immunotherapy could prove to be a critical component of multimodal treatment in the future. The trial is still in its early phase, but hopefully will continue to show promising results.

Learn more about the latest treatment options for mesothelioma

CRS-207 Cancer Vaccine

Later this year, the next phase of a trial around a cancer vaccine known as CRS-207 is expected to begin recruiting patients. CRS-207 is a live bacterium that has been engineered to produce mesothelin, a kind of protein. Patients diagnosed with mesothelioma often demonstrate a high amount of antigens (substances that trigger some kind of immune response) associated with mesothelin.

In their phase 1b clinical trial last year, researchers studied the CRS-207 vaccine in combination with chemotherapy. The vaccine works by inducing an anti-mesothelin response for patients with tumors that express the protein. CRS-207 works hand-in-hand with the body’s immune system and chemotherapy to prevent tumors from growing, and ideally cause them to shrink.

This study focused on patients diagnosed with pleural mesothelioma whose tumors were inoperable. 38 patients participated and received two infusions of CRS-207, followed by up to 6 sessions of chemotherapy, and two more vaccine infusions all spread out with several weeks in between. Ultimately, 35% of patients in the trial saw stable disease and 59% saw some tumor shrinkage, suggesting this could be an effective treatment for pleural mesothelioma.

Aduro Biotech, the manufacturer of CRS-207, announced earlier this month they will be moving forward with a clinical collaboration with Merck, the pharmaceutical company that develops Keytruda. The phase II clinical trial will test the effectiveness of CRS-207 in combination with Keytruda on malignant pleural mesothelioma patients whose disease progressed following previous treatment. These two companies are also testing this combination for gastric cancers in another clinical trial.

After promising results from the initial trial testing CRS-207 with chemotherapy, it will be exciting to see how these two immunotherapies together could potentially benefit the patients.

Showing Support

These are just a few examples of exciting immunotherapy research occurring for mesothelioma right now, but its applications are used throughout the cancer research field for all kinds of cancer. This month and beyond, we can all help show our support for this important research by:

  • Donating to reputable cancer research organizations that are invested in studying immunotherapy, such as the Cancer Research Institute
  • Raising awareness for the importance of this research and participation in clinical trials
  • Reaching out to your local representatives to oppose the suggested budget cuts to the National Institute of Health, which supports much of these research efforts

Immunotherapy is already showing great promise for many cancers. With further development and study, it could help change how we approach all types of cancer forever and bring us closer to a cure.