[5] Common side effects include fatigue, musculoskeletal pain, diarrhea, nausea, infusion-related reactions, rash, decreased appetite and swelling of the limbs (peripheral edema).
[8] The US Food and Drug Administration (FDA) approved it in March 2017, for the treatment of Merkel-cell carcinoma,[7] an aggressive type of skin cancer.
[10] In March 2017, the US Food and Drug Administration (FDA) granted accelerated approval to avelumab for the treatment of people twelve years of age and older with metastatic Merkel-cell carcinoma.
[13] In June 2020, the FDA approved avelumab for the maintenance treatment of people with locally advanced or metastatic urothelial carcinoma that has not progressed with first-line platinum-containing chemotherapy.
Serious adverse reactions that occurred in more than one patient in the trial were acute kidney injury, anemia, abdominal pain, ileus, asthenia, and cellulitis.
[15][9] The most common serious risks are immune-mediated, where the body's immune system attacks healthy cells or organs, such as the lungs (pneumonitis), liver (hepatitis), colon (colitis), hormone-producing glands (endocrinopathies) and kidneys (nephritis).
[16] In May 2017, avelumab was approved in the United States for the treatment of people twelve years of age and older with metastatic Merkel cell carcinoma, including those who have not received prior chemotherapy.
[17] The approval of avelumab was based on data from a single-arm trial of 88 participants with metastatic Merkel cell carcinoma who had been previously treated with at least one prior chemotherapy regimen.