Summary of Clinical Trials

Our lead product, Onrigin™ (laromustine), formerly Cloretazine® (VNP40101M), is an alkylating (DNA-damaging) agent. Our primary registration strategy for this compound is for the treatment of acute myeloid leukemia (AML). The Company plans to file a New Drug Application (NDA) for Onrigin™ (laromustine), based on a pivotal Phase 2 trial in elderly patients with de novo poor-risk AML, with the U.S. Food and Drug Administration (FDA) in early 2009. In addition, clinical trials of Onrigin™ (laromustine) are underway in AML and myelodysplastic syndromes in combination with cytarabine, in AML and MDS in combination with standard remission-induction therapy, in brain tumors in combination with temozolomide, and in advanced hematologic malignancies in combination with hematopoietic cell transplantation. Onrigin™ (laromustine) has received two fast track designations from the U.S. Food and Drug Administration (FDA) for the treatment of: (i) relapsed AML and (ii) elderly poor-risk AML. Onrigin™ (laromustine) has also received orphan drug designation for the treatment of AML in the United States and the European Union.

Preclinical data on Onrigin™ (laromustine) demonstrated broad antitumor activity in in vivo models. It was curative in certain preclinical leukemia models, including mice bearing certain derivatives of a leukemia cell line that was resistant to standard alkylating agents. Onrigin™ (laromustine) was also active against solid tumor models, including lung, colon, and brain cancer, and melanoma. It was curative in mouse models in which a human glioma (brain tumor) or a mouse colon cancer was implanted and growing under the skin. The drug has been shown in preclinical studies to be capable of crossing the blood-brain barrier, a common obstacle in achieving active concentrations of most drugs within the brain.

Our second clinical compound, Triapine®, is a small molecule that in preclinical models inhibits the enzyme ribonucleotide reductase, and therefore prevents the replication of tumor cells by blocking a critical step in DNA synthesis. Triapine® is being evaluated in clinical trials sponsored by the National Cancer Institute (NCI).