Due to favorable results from two pivotal studies, Checkmate 066 and Checkmate 037, Nivolumab became the only new cancer treatment to be fast-tracked through EU approval. In the Checkmate 066 study, patients with BRAF mutation-free, untreated metastatic malignant melanoma were treated with Nivolumab or dacarbazine in first line. The results showed 1-year survival rates of 73% and 42%, respectively, with a risk ratio of 0.42 (P<0.0001)< span="">. The most common adverse reactions were fatigue (20%), pruritus (17%), and nausea (16.5%). And in the Checkmate 037 study, subjects were patients with advanced melanoma who had been previously treated with ipilimumab or who progressed on treatment with the drug. If BRAF mutation-positive patients, these patients could also have been treated with a BRAF inhibitor. An interim analysis showed that Nivolumab significantly improved objective remission rates compared to conventional chemotherapy (32% vs. 11%). Patients who were effective had longer remission periods, typically 2.6-10 months. Patient outcomes were not associated with the presence or absence of BRAF mutations or PD-1 expression status. Serious adverse reactions occurred in 41% of patients in this study, and Grade III and IV adverse reactions occurred in 42% of patients. The most common adverse reactions were abdominal pain, hyponatremia, and elevated transaminases and lipases, however, the most common adverse reaction was rash (21%). In addition, Nivolumab can cause immune-mediated pneumonia, colitis, hepatitis, and nephritis, which may cause renal dysfunction and abnormal thyroid function.