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Immunotherapy is a type of treatment that aims to boost the body’s own immune system to fight cancer cells. In the immune system, the white blood cells, called T-cells, are responsible for fighting infections or cancer cells. However, cancerous cells can continue to change and can develop ways to stop or slow the normal T-cell response.1,2

Researchers have identified pathways where cancer cells suppress the T-cell immune response. One of the pathways that is affected in some non-small cell lung cancers (NSCLC) is the PD-1 receptor and the molecules which bind to the receptor, PD-L1 and PD-L2. When this pathway is affected by the cancer cells, the cancer can grow and spread without being kept in check by T-cells. Two immunotherapy treatments have been developed to target the PD-1 pathway in NSCLC treatment: Keytruda® (pembrolizumab) and Opdivo® (nivolumab).2 In October 2016, a new immunotherapy, called Tecentriq® (atezolizumab) was approved for the treatment of patients with a certain type of metastatic NSCLC.3 In February 2018, the FDA approved Imfinzi® (durvalumab) for the treatment of patients with unresectable, Stage III NSCLC that has not worsened after concurrent platinum-based chemotherapy and radiation therapy.6 Atezolizumab and durvalumab target the PD-L1 pathway. Opdivo® (nivolumab) and Keytruda® (pembrolizumab) may be used for certain patients with metastatic SCLC with progression after platinum based chemotherapy and at least one other line of therapy. In addition, Tecentriq® (atezolizumab) is approved for extensive-stage SCLC as first line-treatment in addition to the chemotherapy drugs etoposide and carboplatin.

How pembrolizumab, nivolumab, atezolizumab, and durvalumab work

Pembrolizumab, nivolumab, atezolizumab, and durvalumab are monoclonal antibodies. Antibodies are a normal part of the immune system that attach to antigens (such as germs) to mark them for destruction by the immune system. Monoclonal antibodies are created in a laboratory to attach to specific antigens on the surface of cancer cells. Keytruda and Opdivo target the PD-1 receptor, blocking the binding and activation of PD-L1. Tecentriq and Imfinzi target the PD-L1 pathway. By blocking these pathways, the body’s immune system is able to fight the cancer.4

Side effects of immunotherapy agents

Like other treatments for cancer, immunotherapy drugs can cause side effects. The side effects vary by treatment and by patient. In general, immunotherapy agents cause side effects that are similar to flu-like symptoms, such as fever, chills, nausea and appetite loss. Fatigue is another common side effect. Patients should discuss a comprehensive list of possible side effects with their doctor.3,4

Research in immunotherapy

Immunotherapy is one of the fastest growing areas of research in cancer treatment. There are several areas of research in immunotherapy, including:

  • Monoclonal antibodies, which target specific tumor antigens
  • Checkpoint inhibitors, which target molecules that are involved in the regulation of immune responses
  • Therapeutic vaccines, which help the immune system target tumor-specific antigens
  • Adoptive T-cell transfer, in which the patient’s T-cells are removed, genetically modified, and then re-introduced into the body 5

In addition, research continues to identify the patients who will most benefit from immunotherapy agents and at what point during treatment these medications should be given for the best clinical outcome.2

Written by: Emily Downward | Last reviewed: January 2020.
  1. T-cell Modulation Group, Cardyff University. Accessed online on 9/30/16 at
  2. Immunotherapy in Lung Cancer Treatment: Current Status and Future Directions, American Society of Clinical Oncology. Accessed online on 9/30/16 at
  3. Genentech, Inc. Accessed online on 11/3/16 at
  4. Chemocare. Accessed online on 9/27/16 at and
  5. IMSH Institute Global Oncology Trend Report: A Review of 2015 and Outlook to 2020. Accessed online on 9/30/16 at
  6. Imfinzi Prescribing Information. AstraZeneca. Published February 2018. Accessed March 1, 2018