27 Jul Mirus Bio study confirms therapeutic breakthrough
Madison, Wis. – A new study offers more proof that Mirus Bio Corp., a Madison biotechnology firm, has developed an effective technique to block the production of disease-causing proteins.
According to Mirus executives, the study confirms the company has produced a delivery platform that could be used as a foundation for RNA interference (RNAi) therapeutics to disable cancer cells, viruses, and genes that cause other metabolic diseases.
Details of the study were published in the online edition of the Proceedings of the National Academy of Sciences.
The technique targets specific cells with RNAi, which acts as a genetic “silencing switch” because it blocks the production of disease-causing proteins inside those cells.
In a first proof-of-concept demonstration, Mirus scientists targeted liver cells and switched off their ability to produce “bad” cholesterol.
David Rozema, PhD and one of the lead authors of the study, said in a release that the lack of effective systemic administration has been the primary impediment to development of RNAi therapeutics for diseases that affect internal tissues and organs.
“This new delivery platform gives us a powerful tool to reach and silence the expression of any gene we might be interested in,” Rozema said.
Mirus Bio, which has received a total of $5.4 million in federal grants since January of 2007, specializes in nucleic acid chemistry and delivery systems for RNAi- and gene-based therapies. It has been granted a United States patent for its new injection delivery method.
According to the company, the discovery of the RNAi mechanism in 1998 revolutionized scientists’ ability to discover the function and role of individual genes. Its discoverers, Drs. Andrew Fire and Craig Mello, were jointly awarded the Nobel Prize in Physiology or Medicine in 2006.
Researchers have been working to develop a wide range of potential medical applications for RNAi, which already has been used to experimentally to treat a few diseases. However, there has been no efficient way to target specific cells where particular diseases occur, such as in key liver cells or inside a tumor. In addition, injected genetic material is quickly cleared from the body.
Mirus researchers say they have overcome these problems by assembling tiny synthetic molecules, called Dynamic PolyConjugates, which shield their genetic “cargo” as they home in on target cells.
Russell Smestad, president of Mirus Bio, said the next step would be to partner with a larger pharmaceutical company to test the delivery platform with specific therapeutic compounds. Successful combinations would then be tested in clinical trials.
Thus far, Smestad said the platform works well on metabolic diseases in the liver, and that may be the best place to start.
He declined to name most of the major pharma companies that Mirus Bio has been in contact with, but acknowledged that Pfizer is a possibility. Mirus already has a research contract with Pfizer.
The company’s top program is a treatment for Muscular Dystrophy, which is being developed collaboratively with Transgene S.A. of Strasbourg, France.
Of the more than $5 million in federal grant money that Mirus Bio has received this year, $2.4 million is being used for the company’s work on liver applications, $1.8 million has been allocated to develop treatments for respiratory infections, $900,000 is being used to extend microRNA detection technologies for clinical research, and $300,000 is being invested in upgrading gene expression technologies.
• Mirus Bio secures $900K grant to develop research tool
• Mirus Bio, Pfizer enter multimillion-dollar research agreement
• Mirus Bio awarded patent on RNA delivery
• Mirus granted European patent for gene therapy
• Mirus provides low-cost way to modify genes