Cybrexa: pH-based tumor targeting

Cybrexa Therapeutics Inc. is developing a targeting technology that taps the pH of the tumor microenvironment to enhance the delivery specificity and decrease the toxicity of small molecule cancer therapies, starting with PARP inhibitors.

Cybrexa uses its alphalex technology to conjugate a cancer agent to a pH-sensitive peptide via an undisclosed linker. The peptide forms a transmembrane α-helix only at a low pH, which occurs in the tumor microenvironment but not normal tissues, and translocates into cells along with its cargo via a non-endocytotic route. Cytoplasmic glutathione cleaves the linker, releasing the free cancer agent inside the cancer cell...