PDCD1 and central nervous system cancer: In a subsequent combination study on a immunocompetent orthotopic murine glioma model, sequential administration of reovirus for 2 weeks followed by PD-1 inhibitors for 1 week showed 100% survival up to 48 days, compared with monotherapies (36 days for reovirus and 22 days for PD-1 blockade (150).