The Eastern Cooperative Oncology Group ( ECOG ) conducted a US-based phase 2 randomized clinical trial from December 28 , 2010 , until July 28 , 2011 , of patients ( N = 245 ) with unresectable stage III or IV melanoma , at least 1 prior therapy , no central nervous system metastases , and ECOG performance status of 0 or 1 .