Atezolizumab-associated myositis in a patient with unresectable hepatocellular carcinoma

Combination treatment with atezolizumab and bevacizumab is the preferred first-line treatment for patients with unresectable or metastatic hepatocellular carcinoma with a Child-Pugh Class A liver function. Reactivation of the antitumor immune response with atezolizumab can result in the development of immune-related adverse events including colitis, skin rash, endocrinopathies, pneumonitis, and nephritis with renal dysfunction. However, the occurrence of myositis with immune checkpoint inhibitors is rare.

We report on a 67-year-old male patient with an initial diagnosis of hepatocellular carcinoma, stage IV, unresectable with underlying cirrhosis who experienced atezolizumab-associated myositis.

Utilization of the American Society of Clinical Oncology guideline on managing immune checkpoint inhibitors adverse events helped guide the ordering of pertinent labs for monitoring and pharmacologic treatment. In our case, atezolizumab-induced myositis was resolved via a combination of corticosteroids, intravenous immunoglobulins, and plasmapheresis.

Recognition of the signs and symptoms of atezolizumab-associated myositis is recommended and utilization of the American Society of Clinical Oncology guideline to guide management and treatment of associated symptoms.