A process and catalyst that provides for the upgrading of a high endpoint gas oil feedstock that contains significant concentrations of organic sulfur compound and organic nitrogen compounds. Included among the sulfur compounds are the dimethyl-dibenzothiophenes and derivative thereof. The catalyst of the process is an additive impregnated composition or a derivative thereof that further comprises cobalt and molybdenum. The process provides for the upgrading the high endpoint gas oil feedstock by significantly reducing the difficult to remove thiophene and nitrogen compounds and the process does this with a significantly reduced hydrogen consumption relative to processes using comparative catalysts.