CDN-A, a cyclic di-nucleotide, serves as a precursor for synthesizing antibody-drug conjugates (ADC) and acts as a potent stimulator of both innate and adaptive immune responses. In humans, these cyclic di-nucleotides, produced endogenously in response to foreign DNA or by bacterial pathogens, activate the innate immune system by inducing the expression of interferon genes [1] [2] [3].