Abstract: The present invention relates to masked IL-15 cytokines, comprising an IL-15 cytokine or functional fragment thereof, a masking moiety and a proteolytically cleavable linker. The masking moiety masks the IL-15 cytokine or functional fragment thereof thereby reducing or preventing binding of the IL-cytokine or functional fragment thereof to its cognate receptor, but upon proteolytic cleavage of the cleavable linker at a target site, the IL-15 cytokine or functional fragment thereof becomes activated, which renders it capable or more capable of binding to its cognate receptor.

Abstract: The present invention relates to masked IL-12 cytokines, comprising an IL-12 cytokine or functional fragment thereof, a masking moiety and a proteolytically cleavable linker. The masking moiety masks the IL-12 cytokine or functional fragment thereof thereby reducing or preventing binding of the IL-cytokine or functional fragment thereof to its cognate receptor, but upon proteolytic cleavage of the cleavable linker at a target site, the IL-12 cytokine or functional fragment thereof becomes activated, which renders it capable or more capable of binding to its cognate receptor.

Abstract: The present invention relates to masked IL-2 cytokines, comprising an IL-2 cytokine or functional fragment thereof, a masking moiety and a proteolytically cleavable linker. The masking moiety masks the IL-2 cytokine or functional fragment thereof thereby reducing or preventing binding of the IL-cytokine or functional fragment thereof to its cognate receptor, but upon proteolytic cleavage of the cleavable linker at a target site, the IL-2 cytokine or functional fragment thereof becomes activated, which renders it capable or more capable of binding to its cognate receptor.

Abstract: The present disclosure provides tumor-specific cleavable linkers and their use in drugs and prodrugs for delivering therapeutics to a tumor cell environment. The present disclosure also provides cleavage products of said drugs and prodrugs, and methods related to the use of the same.