SAN DIEGO--(BUSINESS WIRE)--Metabasis Therapeutics (Nasdaq:MBRX) announced today that MB07133, its product candidate for the treatment of hepatocellular carcinoma (HCC), or primary liver cancer, has been granted Orphan Drug Designation by the Food and Drug Administration (FDA). MB07133 is a novel HepDirect® prodrug of cytarabine monophosphate (araCMP) designed to produce the oncolytically active form, cytarabine triphosphate (araCTP), in the liver tumor where it acts to inhibit cell proliferation and induce apoptosis or cell death. Preliminary results from a Phase 1/2 clinical trial for MB07133, which was completed in the second quarter of this year, were presented at the Annual Meeting of the American Association for Cancer Research (AACR) in April 2007. This first dose escalation trial showed that MB07133, at doses up to 2400 mg/m2/day, 7 day continuous IV infusion, was well tolerated in patients with unresectable HCC. No clinically important dose-limiting toxicities associated with the therapy and few treatment-related hepatic adverse events were observed. Additionally, the trial revealed encouraging signs of drug activity evidenced by tumor shrinkage and disease stabilization. Intra-hepatic tumor reduction was observed in seven patients (25% of those studied), and increased median overall survival was seen in these patients relative to the other patients in the study.
