Based on pre-clinical data described above the researchers have recently completed and published a phase 2 trial in patients with recurrent prostate cancer using a low-dose, sustained release trasndermal patch of GTN. The GTN was supplied as Minitran™ (nitroglycerin) transdermal delivery system (3M Company, St. Paul, Minnesota) in an open label, non-blinded fashion. GTN is a nitrodonor that has been used in the management of angina for over 100 years with a well-documented safety and tolerability record and has never been associated with carcinogenesis. Their pre-clinical studies have demonstrated that very low molar concentrations of nitric oxide donors are required to attenuate hypoxia-induced malignant phenotypes.