Mesothelioma Case Study: Keytruda Side Effect Treated with Plasma Exchange

Keytruda side effectGerman mesothelioma doctors say a Keytruda side effect that causes the heart to swell can be treated by “cleaning” the blood plasma. 

The team shared the details of a recent mesothelioma case in Translational Lung Cancer Research. The mesothelioma patient developed a condition called myocarditis after treatment with pembrolizumab (Keytruda). 

The Keytruda side effect is rare but serious. The good news is that cleaning the blood through a process called plasmapheresis restored the patient’s heart function. The article could help other doctors if any of their mesothelioma patients have similar problems.  

Myocarditis as a Keytruda Side Effect

Keytruda is a type of immunotherapy drug called an immune checkpoint inhibitor. It is approved to treat patients who have already tried other mesothelioma therapies. 

Immune checkpoint inhibitors disable a mechanism cancer cells use to protect themselves. In the case of mesothelioma, the protection comes from overexpression of the protein PD-1. Keytruda blocks PD-1. 

But this powerful drug can also cause complications. The German case study focused on a rare but serious Keytruda side effect called myocarditis. Myocarditis is when the heart muscle swells and is not able to pump as much blood as it should. 

Myocarditis can cause shortness of breath, chest pain, weakness, and rapid or abnormal heart rhythms. Viral infections are the most common cause. But it can also be a side effect of mesothelioma treatment. 

German Team Finds Success with Plasmapheresis

The 75-year-old pleural mesothelioma patient in the German case study came in with muscle weakness, shortness of breath, double vision, and drooping eyelids. Doctors suspected a heart problem. Tests showed that certain cardiac biomarkers were elevated. But the patient had no history of heart disease. 

The patient had recently completed two cycles of mesothelioma treatment with pembrolizumab. The team wondered if the problems could be a Keytruda side effect. 

“Because cardiac catheterization revealed no relevant coronary lesions, immune checkpoint inhibitor-associated myocarditis and MG were suspected,” writes the report’s author, Sanziana R I Schiopu of Ludwig Maximilian University Munich. 

MG is an autoimmune disorder that causes neuromuscular problems.  

Steroids and electrical cardioversion did not help either Keytruda side effect. Doctors eventually tried plasmapheresis. Plasmapheresis involves cycling the liquid part of the blood through a machine to clean it. It is one way to treat MG. 

Ten cycles of plasmapheresis did help the MG. It also resolved the heart-related Keytruda side effect. The mesothelioma patient was alive a year later with no lasting problems. 

“We conclude that patients showing no improvement after steroid therapy for immune checkpoint inhibitor-related myocarditis should be evaluated for plasma exchange, which appears to be an effective treatment option,” concludes Dr. Schiopu.

Immunotherapy shows promise for malignant mesothelioma, which is very hard to treat. Last year, the FDA approved two other immunotherapy drugs as a first-line mesothelioma treatment. 


Schiopu, S, et al, “Pembrolizumab-induced myocarditis in a patient with malignant mesothelioma: plasma exchange as a successful emerging therapy-case report”, February, 2021, Translational Lung Cancer Research,

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