Breakthrough Offers Hope for Safer Cancer Immunotherapy
For many cancer patients, immune checkpoint inhibitors (ICIs) have dramatically improved survival rates. However, these powerful therapies carry a risk of severe side effects, including inflammation of the heart tissue. Now, research from Cincinnati Children’s Hospital offers a potential solution to mitigate this dangerous complication, paving the way for safer and more effective cancer treatment.
The Promise of Immune Checkpoint Inhibitors
Immune checkpoint inhibitors, such as Keytruda and Opdivo, have revolutionized cancer treatment since their initial approval in 2011. The 2018 Nobel Prize in Medicine was awarded to James Allison and Tasuku Honjo for their groundbreaking discovery of these therapies 1. ICIs work by releasing the brakes on the immune system, allowing T cells to recognize and destroy cancer cells.
A Serious Side Effect: Myocarditis
Despite their success, ICIs can sometimes trigger the immune system to attack healthy tissues, most critically the heart. This can lead to myocarditis, an inflammation of the heart muscle, occurring in approximately 2% of patients receiving ICIs 1. Alarmingly, about half of patients who develop myocarditis die from the complication, even if their cancer is in remission.
New Research Identifies Key Factor in Heart Damage
Scientists at Cincinnati Children’s Hospital have made a significant discovery regarding the cause of ICI-induced myocarditis. Using a newly developed mouse model that accurately mimics the condition in humans, researchers identified CD8 T-cell-derived tumor necrosis factor (TNF) as a key contributor to the inflammation 2.
The research revealed that the heart damage isn’t caused by the depletion of cancer-specific T cells, but rather by the creation of “autoreactive” T cells that mistakenly target healthy heart muscle cells alongside cancer cells. Blocking TNF signaling through the TNFR2 gene product in mice successfully prevented the inflammatory cycle from starting in the heart 2.
Potential for Targeted Prevention
“Checkpoint inhibitors allow TNF signaling to trigger antigen-specific CD8 T cells on cardiac myocytes, resulting in life-threatening arrhythmias,” explains Jeffery Molkentin, PhD, director of the Division of Molecular Cardiovascular Biology at Cincinnati Children’s 2. “We used a targeted method of blocking TNF to prevent this cycle in our mouse models. If these results can be replicated in humans, TNF blockade should prevent cardiac toxicity without compromising the antitumor benefits of ICIs.”
Next Steps and Future Research
Further research is crucial to determine the safety and optimal duration of a targeted TNF inhibitor for human use. TNFR2-specific antibodies are currently in development. Researchers also aim to investigate whether similar approaches can prevent immune-related adverse events affecting other organs 1.
Chandrashekhar Pasare, DVM, PhD, director of the Division of Immunology at Cincinnati Children’s, emphasizes the importance of this discovery: “This study makes a very crucial discovery that shows how to uncouple anti-tumor efficacy from cardiac toxicity. These findings have major implications for treating or avoiding immune related adverse events in cancer patients receiving immune check point blockade.” 1
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