Molecular Insight Pharmaceuticals' SAAC(TM) Technology Data Published in Bioconjugate Chemistry; Biotin Derivatives May Expand Applications of Radiolabeling Technologies.

CAMBRIDGE, Mass. -- Molecular Insight Pharmaceuticals, Inc. announced today publication of two studies regarding the potential use of its Single Amino Acid Chelate (SAAC(TM)) technology for linking biotin and avidin to two common nuclear imaging and radiotherapeutic isotopes, technetium and rhenium. The studies, published in the current issue of Bioconjugate Chemistry, examine the potential utility of SAAC technology and create new avenues for developing targeted imaging agents and radiotherapeutics. E[acute accent]SAAC, Molecular Insight's unique metal-binding chemistry platform technology, incorporates a metal-binding (chelating) group into a single amino acid construct that can rapidly and efficiently bind to medically useful isotopes for diagnostic and therapeutic uses. Due to their ability to form stable natural complexes, biotin and avidin are widely used in biomedical research and have potential in imaging and targeted radiopharmaceuticals. In the SAAC applications, one of the pair is linked to an agent such as an antibody that targets a specific site in the body; the other (biotin) is linked to a radionuclide that can be imaged or that can deliver targeted radiotherapy. E[acute accent]The studies suggest proof-of-concept for the application of SAAC analogues to create radiolabeled biotin derivatives with the widely-used radionuclides technetium and rhenium for use as targeting vectors. They build on the work by Molecular Insight and its academic collaborators to demonstrate the potential utility of SAAC technology to create a wide range of targeted imaging agents and radiotherapeutics. E[acute accent]The SAAC studies are part of Molecular Insight's objective to expand its platform technologies in imaging and targeted radiopharmaceuticals that the company can apply in its efforts to build a pipeline beyond its lead clinical candidates, Zemiva(TM) (iodofiltic acid I 123) and Azedra(TM) (Ultratrace(TM) MIBG). Molecular Insight has two other platform technologies, Ultratrace and Nanotrace Discovery(TM). Ultratrace is a proprietary solid-phase radiolabeling technology which enables the development of ultrapure, highly specific radiopharmaceuticals, and Nanotrace Discovery is a targeting platform that allows for the rapid creation and screening of new leads for molecular targeting of disease. E[acute accent]In the paper, the researchers described and characterized a number of SAAC-biotin compounds bound with technetium. They demonstrated the ability of the analogues to bind avidin in vitro and in in vivo tumor models. The researchers also showed that the compounds are resistant to breakdown by biotinidase enzymes. E[acute accent]A separate paper published in the same issue of the journal suggests that SAACQ analogues can be used to develop both fluorescent and radionuclide probes with technetium and rhenium. Radiopharmaceutical development is often hampered by the inability to image a compound's behavior at the cellular and subcellular level. SAACQ biotin probes can enable such imaging, and the development of complementary probes allows direct correlation of in vitro and in vivo imaging studies. E[acute accent]The papers are entitled, "Extension of Single Amino Acid Chelate Concept (SAAC) to Bifunctional Biotin Analogues for Complexation of the M(CO)3+1 Core (M=Tc and Re): Syntheses, Characterization, Biotinadase Stability, and Avidin Binding" and "Isostructural Re and 99mTc Complexes of Biotin Derivatives or Fluorescence and Radioimaging Studies." Authors on the first paper are Shelly James, Damian Allis, Ph.D., and John Zubieta, Ph.D., Syracuse University; John Valiant, Ph.D., McMaster University; and Kevin Maresca, Ph.D., and William Eckelman, Ph.D., and John Babich, Ph.D., of Molecular Insight. Authors on the second paper are Shelly James and John Zubieta, Ph.D., of Syracuse University; Kevin Maresca, Ph.D., and John Valiant, Ph.D., of McMaster University; and John Babich, Ph.D., and Laurie Doering of Molecular Insight.

E[acute accent]About Molecular Insight Pharmaceuticals, Inc.

E[acute accent]Molecular Insight Pharmaceuticals is a biopharmaceutical company focused on the research, development and commercialization of innovative molecular imaging pharmaceuticals and targeted radiotherapeutics. The company's product candidates target markets with significant unmet needs in cardiology, oncology, and neurology. Molecular Insight's lead product candidate, Zemiva (iodofiltic acid I 123) is a radiolabeled fatty acid analog that is in development as a molecular imaging pharmaceutical for the diagnosis of insufficient blood flow to the heart, or cardiac ischemia. The company's second lead product candidate, Azedra (Ultratrace MIBG), is in development for the diagnosis and treatment of neuroendocrine tumors. Molecular Insight Pharmaceuticals is based in Cambridge, Massachusetts. The company's Website is www.molecularinsight.com.