This open-label, radiolabeled, single 100-mg dose study in 6 healthy male volunteers has been designed to further the understanding of human metabolism of lorlatinib. A prior radiolabel study using [14C]lorlatinib (study B7461004) identified an unexpected major metabolite in plasma; a benzoic acid metabolite (M8) resulting from cleavage of the amide and aromatic ether bonds of lorlatinib, accounting for 21.0% of the circulating radioactivity. However, due to the position of the 14C radiolabel on the carbonyl carbon, the metabolic fate of the larger fragment of lorlatinib resulting from this cleavage, the pyrido-pyrazole substructure, could not be determined. In this current study, the radiolabel will be on the pyrazole ring allowing for monitoring the metabolic fate of the pyrido-pyrazole part of the lorlatinib molecule cleaved during the formation of the M8 metabolite. Since M8 will not be radiolabeled, its concentrations in plasma will be determined using a validated assay.