PEN-SP9

PEN-SP9 is a cell-penetrating peptide conjugate designed to specifically inhibit the pathological hypersecretion of mucus in the airways, a hallmark of several serious respiratory disorders. It consists of a therapeutic peptide snippet, SP9, which mimics a binding interface of synaptotagmin, conjugated to a cell-penetrating peptide, PEN (derived from penetratin). The drug works by blocking the calcium-triggered interaction between synaptotagmin and its cooperating proteins (likely SNARE complexes) within airway secretory cells. This action prevents the massive, inflammation-driven exocytosis of mucin-containing vesicles while sparing the low-level baseline secretion necessary for normal lung lubrication and defense. Developed through a collaboration between Stanford University, MD Anderson Cancer Center, and Ulm University, PEN-SP9 is being investigated for the treatment of asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, and viral respiratory infections.