CTLA4 and neoplasm: In the phase I trial of 86 patients with unresectable stage III or IV melanoma treated with either concurrent or sequential ipilimumab and nivolumab, concurrent CTLA-4 and PD-1 blockade achieved a higher ORR of 40%, with 53% of patients achieving CR or PR at the maximum doses tested, whereas 31% of responders demonstrated tumor regression of 80% or more even with bulky disease.18