Brazil has completed the second phase of trials for nivolumab, a drug to treat common skin cancer, Medical Xpress reports. The drug's mechanism of action is based on increasing the activity of a person's own immune cells. Nivolumab is a synthetic antibody that blocks the PD-1 receptor, which inhibits immune cell function. As a result, the body begins to destroy metastases and primary tumors more effectively. Such therapy can have serious side effects, so it is used only in severe cases when other methods have not worked. Twenty-four patients took part in the trial. They all received nivolumab at a dose of 3 mg/kg every two weeks until the cancer progressed or side effects developed. Fourteen patients (58.3%) benefited from the treatment and their bodies demonstrated an immune response. Treatment-related adverse effects were observed in six patients (25%), and one discontinued nivolumab because of toxicity. The side effects from radiation, however, were more pronounced. Rodrigo R. Munoz, lead author of the paper, said that the study provides additional evidence supporting the use of immune checkpoint blockers as standard therapy for squamous cell skin cancel. The trial has only strengthened oncologists' opinions about the confidence in the benefits of various immune checkpoint inhibitors in cancer.