Val-Cit-PAB-OH is primarily used in the development of antibody-drug conjugates (ADCs), which are targeted cancer therapies. It serves as a cleavable linker that connects the cytotoxic drug to the antibody. This linker is designed to remain stable in the bloodstream but releases the drug once inside the target cancer cells, enhancing the precision and efficacy of the treatment. Its application is crucial in minimizing damage to healthy tissues while maximizing the therapeutic impact on cancer cells.