This is an old video by Dan Chen (who is one of the pioneers in cancer immunotherapy and is now the chief medical officer for IGM Bioscience). It is a classic and particularly easy-to-understand for patients.
This article is meant for patients. I have also written an article on immunotherapy on LinkedIn for health professionals.
In Australia, a CTLA-4 inhibitor, ipilimumab (Yervoy) was approved for metastatic melanoma in 2011 and since then, PD-1 inhibitors; pembrolizumab (Keytruda) and nivolumab (Opdivo) and PD-L1 inhibitors; atezolizumab (Tecentriq), avelumab (Bavencio) and Durvalumab (Imfinzi) have been approved for multiple cancers including lung, renal, bladder and head and neck cancers. These checkpoint inhibitors or monoclonal antibodies are often referred to as the popular ‘immunotherapy’. Watch a video on how cancer immunotherapy works.
Why is this important?
Immunotherapy is currently widely used in patients with advanced melanoma and lung cancer which are two of the top five most common cancers in Australia (the others being breast, prostate and colorectal cancer). The indications for immunotherapy are also expanding rapidly as pharmaceutical companies race to find evidence for its effectiveness in other cancers.
What do you need to know?
While immunotherapy works only in some patients, it has led to long-lasting responses and significant improvements in life expectancy in cancers which previously had very poor prospects.
Used as a single drug, immunotherapy is generally well-tolerated. Though theoretically, immunotherapy could cause side effects in any part of the body, the most common side effects are diarrhea, tiredness, rash, nausea and low thyroid hormone levels which are easily managed. However, some patients (10-20%) sustain severe side effects and if in doubt, patients should contact their oncology team to discuss suspicious symptoms.
Unfortunately, combination immunotherapy (e.g nivolumab/ipilimumab) which is increasingly being used in melanoma and other cancers puts patients at a significantly higher risk of severe side effects. In studies, more than half (55%) of patients on the combination of nivolumab/ipilimumab sustained severe side effects. Considerably more patients can have inflammation of the colon, liver, kidneys or lungs which can be potentially life-threatening if not treated early. Patients with suspected side effects from combination therapy should seek help urgently from their oncology team for early investigation and treatment.
Immunotherapy is believed to be cleared from the human body the same way as our own antibodies. As this does not involve specific drug metabolizing enzymes, no major drug interactions are expected. However, due to how these treatments exert their effects by stimulating the immune system, patients should not be on steroids or if this cannot be avoided, be on the lowest steroid dose possible.
Patients with auto-immune conditions like rheumatoid arthritis or Crohn's disease are at risk of flare-up of their disease with immunotherapy. It is possible to give immunotherapy to patients with stable auto-immune conditions but unfortunately, sometimes it can be hard to balance treatment for both the auto-immune disease and cancer. These patients need to be monitored closely for signs of flare-up.
Whether or not patients on immunotherapy can receive routine vaccinations is another question that frequently comes up. The consensus is that it is safe to receive the flu shot during treatment with PD-1 inhibitors (pembrolizumab, nivolumab) and PD-L1 inhibitors (avelumab, durvalumab). Patients receiving CTLA-4 inhibitors such as ipilimumab should wait at least 6-8 weeks after the last dose. Live vaccines should not be given during treatment with immunotherapy and for at least 6 months afterwards. In any case, live vaccines should not be given in patients who have poorly controlled cancer.
What does the future hold?
Various combinations and types of immunotherapy are being trialled in almost every cancer and new drugs are rapidly being developed. There are many challenges to overcome but immunotherapy in its various forms will no doubt be the future of cancer care. Right now, we are just scratching the surface.
If you are interested to know more about immunotherapy or other cancer treatments, leave your questions in the comment section below or sign up for monthly updates.