What Is Immunotherapy and How Does It Work for Mesothelioma?

Understanding Immunotherapy

What Is Immunotherapy

Immunotherapy is a type of cancer treatment that boosts the body's natural defenses to fight cancer. It works by enhancing the immune system's ability to recognize and destroy cancer cells. The immune system is the body’s defense mechanism against infections, diseases, and abnormal cells, including cancer cells. However, cancer cells often evade detection by the immune system or suppress immune responses, allowing them to grow and spread. Immunotherapy aims to overcome these challenges by stimulating or restoring the immune system's ability to combat cancer.

How Does the Immune System Fight Cancer

The immune system includes various cells and molecules, such as T-cells, B-cells, natural killer (NK) cells, and antibodies, that work together to identify and destroy abnormal cells. When functioning correctly, the immune system can distinguish between healthy cells and those that are foreign or damaged, such as cancer cells. However, cancer cells can develop mechanisms to evade immune detection, such as downregulating certain molecules on their surface or secreting substances that suppress immune responses. Immunotherapy seeks to counteract these mechanisms and empower the immune system to target cancer effectively.

Types of Immunotherapy for Mesothelioma

Several types of immunotherapy have shown promise in treating mesothelioma, each working through different mechanisms to enhance the immune response against cancer.

Immune Checkpoint Inhibitors

• Mechanism: Immune checkpoint inhibitors are drugs that block proteins used by cancer cells to evade the immune system. These proteins, known as checkpoints, normally prevent the immune system from attacking healthy cells, but cancer cells exploit them to avoid being destroyed.
• Common Drugs: Pembrolizumab (Keytruda), nivolumab (Opdivo), and ipilimumab (Yervoy) are examples of checkpoint inhibitors. They target proteins such as PD-1, PD-L1, and CTLA-4, which are found on T-cells or cancer cells. By blocking these proteins, checkpoint inhibitors enable T-cells to recognize and kill cancer cells.
• Use in Mesothelioma: Checkpoint inhibitors have been approved for use in treating certain types of mesothelioma, particularly in patients with unresectable or advanced disease. Clinical trials have shown that these drugs can help control the disease and, in some cases, lead to long-term remission. For more detailed treatment options, refer to main treatment options for mesothelioma.

CAR T-Cell Therapy

• Mechanism: Chimeric Antigen Receptor (CAR) T-cell therapy involves modifying a patient’s T-cells to better recognize and attack cancer cells. T-cells are extracted from the patient’s blood, genetically engineered to express receptors specific to cancer cells, and then infused back into the patient.
• Application in Mesothelioma: CAR T-cell therapy is still experimental in mesothelioma, but early trials are exploring its potential. Researchers are working to identify suitable targets on mesothelioma cells that can be attacked by CAR T-cells. Understanding the causes of mesothelioma can aid in identifying these targets.

Cancer Vaccines

• Mechanism: Cancer vaccines are designed to stimulate the immune system to attack specific cancer-related antigens. Unlike traditional vaccines that prevent disease, cancer vaccines are therapeutic and aim to treat existing cancer by inducing a targeted immune response.
• Use in Mesothelioma: Research is ongoing to develop vaccines that target mesothelin, a protein commonly overexpressed in mesothelioma cells. These vaccines could help train the immune system to recognize and destroy mesothelioma cells more effectively. For more information on early detection, see early detection of mesothelioma.

Cytokine Therapy

• Mechanism: Cytokines are proteins that play a crucial role in regulating the immune system. Cytokine therapy involves using synthetic or natural cytokines to boost the immune response against cancer.
• Types Used: Interleukin-2 (IL-2) and interferon-alpha are examples of cytokines that have been studied for their potential to enhance immune activity against mesothelioma.

Benefits of Immunotherapy for Mesothelioma

Immunotherapy offers several potential benefits, particularly for patients with advanced mesothelioma or those who have not responded well to conventional treatments.

Targeted Immune Response

• Precision: Immunotherapy specifically targets cancer cells while sparing healthy cells, which can lead to fewer side effects compared to traditional treatments like chemotherapy and radiation. For more on chemotherapy, see how chemotherapy works for mesothelioma.
• Long-Term Control: In some patients, immunotherapy can lead to durable responses, where the immune system continues to control the cancer for extended periods, even after treatment has ended.

Synergistic Effects with Other Treatments

• Combination Therapy: Immunotherapy can be combined with other treatments, such as chemotherapy, radiation, or surgery, to enhance overall effectiveness. For example, checkpoint inhibitors may be used alongside chemotherapy to improve patient outcomes. For more on managing side effects, see managing side effects of mesothelioma treatment.

Potential for Remission

• Long-Term Survival: While not all patients respond to immunotherapy, those who do may experience significant benefits, including long-term remission and improved survival rates. This has been particularly notable in certain cancers where immunotherapy has revolutionized treatment.

Challenges and Side Effects of Immunotherapy

Despite its potential, immunotherapy is not without challenges and risks. Understanding these can help patients and doctors make informed decisions about treatment.

Immune-Related Side Effects

• Autoimmunity: By enhancing the immune system, immunotherapy can sometimes cause it to attack healthy tissues, leading to autoimmune-like side effects. These can include inflammation of the lungs (pneumonitis), liver (hepatitis), intestines (colitis), or other organs.
• Managing Side Effects: Close monitoring and prompt treatment of side effects are essential. In some cases, immunotherapy may need to be paused or stopped if side effects become severe. For more on common side effects, see common side effects of mesothelioma treatments.

Variable Response

• Not All Patients Respond: Immunotherapy is not effective for all patients. The variability in response is likely due to differences in tumor biology, the immune system, and other factors that are not yet fully understood.
• Biomarkers for Response: Researchers are working to identify biomarkers that can predict which patients are most likely to benefit from immunotherapy. For example, tumors with high levels of PD-L1 expression are more likely to respond to checkpoint inhibitors. For more on prognosis, see prognosis for mesothelioma.

Cost and Accessibility

• High Cost: Immunotherapy treatments can be expensive, and access may be limited depending on a patient’s location and healthcare coverage. This is a significant consideration in the overall management of mesothelioma.

The Future of Immunotherapy in Mesothelioma Treatment

The future of immunotherapy for mesothelioma looks promising, with ongoing research focused on improving the effectiveness of current treatments and developing new approaches.

Personalized Medicine

• Tailored Treatments: Advances in genetic profiling and immunogenomics may lead to more personalized immunotherapy treatments, tailored to the specific characteristics of a patient’s tumor and immune system.
• Combination Strategies: Researchers are exploring various combination strategies that include immunotherapy, such as combining checkpoint inhibitors with targeted therapies or vaccines, to enhance the immune response and overcome resistance. For more on prevention, see prevention of mesothelioma.

Emerging Therapies

• New Checkpoint Inhibitors: New checkpoint inhibitors targeting different immune pathways are being developed and tested in clinical trials.
• Next-Generation CAR T-Cells: Ongoing research aims to improve CAR T-cell therapies by making them more effective and reducing the risk of side effects.

Conclusion

Immunotherapy represents a groundbreaking approach in the treatment of mesothelioma, offering new hope for patients with this challenging cancer. By harnessing the power of the immune system, immunotherapy can provide targeted and effective treatment, especially for those who do not respond to traditional therapies. While there are challenges and potential side effects, the continued advancement of immunotherapy research holds promise for improving outcomes and extending the lives of mesothelioma patients. As this field evolves, immunotherapy is likely to become an increasingly important part of the treatment landscape for mesothelioma and other cancers.

Sources:

• National Cancer Institute - Immunotherapy for Cancer
• American Cancer Society - How Immunotherapy Is Used to Treat Cancer
• Mayo Clinic - Immunotherapy for Mesothelioma
• Centers for Disease Control and Prevention (CDC) - Immunotherapy in Mesothelioma