Threshold Pharmaceuticals, Inc. is a biotechnology company focused on the discovery and development of drugs targeting the microenvironment of solid tumors and the bone marrows of some hematologic malignancies (blood cancers) as treatments for patients living with cancer. The Company's hypoxia activated prodrug product candidates, including TH-302, are designed to specifically target the hypoxic microenvironment of tumors by selective activation of the prodrug to release a potent cytotoxin. The Company's focus is on product candidates for the treatment of patients with cancer. The Company's clinical development efforts are focused on TH-302, for which the Company entered a license and co-development agreement with Merck KGaA, on February 2, 2012, for worldwide development and commercialization. As of December 31, 2011, TH-302 is in Phase I, Phase II and Phase III clinical trials. The Company reported updated results from the Phase I monotherapy trial of TH-302.