The invention provides a method for treating a tumor in a human comprising administering to the tumor a dose of a pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) an adenoviral vector comprising a nucleic acid sequence encoding TNF-.alpha. operably linked to a promoter, wherein the dose comprises about 1.times.10.sup.7 to about 4.times.10.sup.12 particle units (pu) of replication-deficient adenoviral vector, at least once in a therapeutic period comprising up to 10 weeks, whereby the tumor in human is treated.