A substance being studied in the treatment of several types of cancer. It blocks the action of certain enzymes, and it may help keep cancer cells from growing and spreading. It is a type of serine protease inhibitor.

An orally bioavailable, 3-amidinophenylalanine-derived, second generation serine protease inhibitor prodrug targeting the human urokinase plasminogen activator (uPA) system with potential antineoplastic and antimetastatic activities. After oral administration, upamostat is converted to the active N alpha-(2,4,6-triisopropylphenylsulfonyl)-3-amidino-(L)-phenylalanine-4-ethoxycarbonylpiperazide (WX-UK1), which inhibits several serine proteases, particularly uPA; inhibition of uPA may result in the inhibition of tumor growth and metastasis. uPA is a serine protease involved in degradation of the extracellular matrix and tumor cell migration and proliferation.