Immunotherapy is a form of cancer treatment that encourages the body’s immune system to attack cancer cells. Treatment can shrink tumors or slow their spread.
What Is Immunotherapy?
Immunotherapy, also known as immune-oncology and biologic therapy, is a form of lung cancer therapy that uses the body’s immune system to fight cancer. Normally, a healthy immune system is able to recognize and deploy cells (like T-cells or white blood cells) to fight viruses and bacterial infections. However, cancer cells are often able to hide from the immune system because they were normally-functioning and healthy cells at one time. Subsequently, the immune system has a harder time finding and attacking cancerous cells.
Overall, the prognosis for advanced-stage small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) is poor. The combined five-year survival rate is less than five percent. Too, lung cancer is the leading cause of cancer death in the country. Traditional treatments to length quality years of life with loved ones include chemotherapy, radiation therapy, and/or surgery. In recent years, the introduction of immunotherapeutic medicine as a line of cancer treatment has improved the prognosis for many patients while reducing recovery times from treatment.
Types of Immunotherapy
The term “immunotherapy” refers to a type of cancer therapy that encourages the body’s immune system to attack cancer cells. Within the category of immunologic therapy treatments, there are three primary modes of immunotherapy currently being researched and prescribed.
To date, checkpoint inhibitors are the only immunotherapy to receive broad approval from the Food and Drug Administration (FDA) for the treatment of advanced-stage lung cancer. The remaining two, cancer vaccines and adoptive T-cell therapy, are available only to patients in clinical trials.
Unlike vaccines for the flu or chickenpox which aim to prevent illness, cancer vaccines promote the body’s current ability to fight cancer. Cancer vaccines pinpoint proteins found in lung cancer but not healthy cells. Adoptive T-cell therapy, however, tailors the patient’s own T-cells after removing them to fight his or her specific form of cancer.
Lab-altered T-cells are returned to the body via infusion, similar to the intravenous (IV) infusions given for immune checkpoint inhibitors and cancer vaccines. Typically, immunotherapy infusions are administered in an outpatient setting (though some patients may stay longer for observation) on a set schedule a few times a month up to once every 6 weeks. Treatment may continue for as long as it is effective and side effects are low.
Clinical trials for the following targeted antibody cancer treatments are ongoing and often include chemotherapy:
- Bevacizumab (Avastin®)
- Necitumumab (Portrazza®)
- Ramucirumab (Cyramza®)
Immune Checkpoint Inhibitors
Immune checkpoint inhibitor therapy is the field of immune-oncology with the most research and the most success in patients. The “immune checkpoints” are parts of immune cells that tell the system when to initiate a response. Cancer cells are able to hide from these checkpoints by imitating healthy cells. Cancer medicine made of immune checkpoint inhibitors stop proteins (usually PD-1 or PD-L1) from blocking immune cells from killing tumors. When the medication is successful, tumors will shrink and/or spread or grow more slowly. Generally, patients with lung tumors high in PD-L1 levels respond better to treatment and can begin immunotherapy sooner.
In 2015, nivolumab (Opdivo®) became the first immunotherapeutic medication approved by the FDA for patients with squamous cell type lung cancer whose first line of treatment was no longer successful. Over the next year, the FDA approved additional immune checkpoint inhibitors, or immunomodulators, for patients with all types of NSCLC, for patients whose tumors expressed a specific gene, and as the first line of therapy for others.
Up to now, FDA-approved immunotherapy drugs include the following immune checkpoint inhibitors:
- Atezolizumab (Tecentriq®)
- Durvalumab (Imfinzi®)
- Nivolumab (Opdivo®)
- Pembrolizumab (Keytruda®)
Side Effects of Treatment
For drugs that elicit an immune response from the body like Keytruda and Opdivo, side effects of treatment are similar to general immune responses. Common side effects of immune checkpoint inhibitors include:
- Constipation and diarrhea
- Joint pain
- Loss of appetite
- Skin rash
These side effects are generally well-controlled with over-the-counter medication. However, new or increasingly harsh symptoms should be reported to your doctor immediately.
Severe side effects are less common but include allergic reactions to the infusions (i.e. fever, chills, flushed face, itchy skin, trouble breathing, etc.) and autoimmune reactions to immune therapy. Autoimmune reactions occur when the immune system attacks healthy and cancerous cells alike throughout the body (i.e., intestines, liver, kidney, and other organs).
Who Can Receive Immunotherapy?
Because immunotherapy is a form of cancer therapy, the medication is designed to focus its efforts on specific cancerous cells. So far, only certain types of lung cancer will be able to receive the above forms of immunotherapy. Proteins like PD-L1, and more recently CTLA-4, may need to be found in higher levels in lung tumors to make the individual a good candidate for lung cancer immunotherapy.
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