Arrowhead Research Subsidiary, Insert Therapeutics, Treats First Patient with Nano-Engineered Anti-Cancer Therapeutic

"The initiation of the clinical development phase for IT-101 is animportant milestone for Insert Therapeutics. It demonstrates ourcommitment to bringing innovative therapies to the clinic that addresssignificant, unmet patient needs," said Dr. Thomas Schluep, ChiefScientific Officer at Insert Therapeutics.

The study is an open-label, dose-escalation Phase I study inpatients with inoperable or metastatic solid tumors and has beendesigned to evaluate the safety, tolerability and pharmacokinetics ofIT-101. Insert expects that between 24 and 48 patients will beenrolled in the study during its course. The study is currently beingconducted at The City of Hope Cancer Center (COH) in Duarte, CA, whereYun Yen, MD., Ph.D. will lead the study.

"We congratulate the team at Insert on this latest success," saidR. Bruce Stewart, Arrowhead's Chairman. "While the Phase I study isunderway, Insert will continue preparations for IT-101's furtherclinical trials and the development of its next therapeuticcandidates."

Animal studies using IT-101 showed excellent anti-cancer activity,including complete remission of certain kinds of lung cancer, amongothers. For more information about Insert and IT-101, please visitInsert's website at www.insertt.com.

About IT-101

IT-101 is a combination of its patented polymer technology,Cyclosert(TM), and the anti-cancer compound camptothecin. Insert'sproprietary Cyclosert delivery system is based on small cyclicrepeating molecules of glucose called cyclodextrins. Using modifiedcyclodextrins as building blocks, Insert has developed an entirely newproprietary class of materials called linear cyclodextrin-containingpolymers. To the company's knowledge, Cyclosert is the firstnanoparticulate drug delivery platform to be designed de novo andsynthesized specifically to overcome limitations in existing deliverytechnologies used for the systemic delivery of therapeutics. Thepolymers were invented at Caltech in the lab of Dr. Mark Davis, aprofessor in Chemical Engineering and founder of Insert, and licensedexclusively to Insert.

Cyclosert polymers have been synthesized over a broad range ofmolecular weights providing tunable properties for systemic drugdelivery that improve localization of active drug at the targettissue. This feature of the Cyclosert technology provides greatflexibility for overcoming multiple hurdles encountered in formulationand delivery.

Discovered in the 1960s, camptothecin is a naturally occurring,water-insoluble alkaloid that has established potent activity againsta broad spectrum of cancer types. Although analogues of camptothecin(e.g., irinotecan and topotecan) continue to realize nearly $1 billionin worldwide sales annually, camptothecin itself has not beencommercialized due to its poor solubility and unfavorablepharmacokinetics. In numerous animal studies conducted by Insert,treatment with IT-101 result in protracted anti-tumor activities thatare substantially more effective than irinotecan or camptothecinadministered alone.

About Insert Therapeutics, Inc.

Insert Therapeutics, Inc., a majority-owned subsidiary ofArrowhead Research Corporation (NASDAQ:ARWR), is using itsproprietary, nano-engineered, polymeric delivery system,Cyclosert(TM), to design, develop and commercializedrug-delivery-enhanced small-molecule therapeutics and nucleic acids.Cyclosert uses cyclodextrins as building blocks to create an entirelynew class of biocompatible materials -- linear cyclodextrin-containingpolymers that are nontoxic and nonimmunogenic at therapeutic doses.The company is pursuing this goal through its internal research anddevelopment, and also through collaborations and partnerships withpharmaceutical and biotechnology companies.

About Arrowhead Research Corporation

Arrowhead Research Corporation (www.arrowheadresearch.com) is adiversified nanotechnology company structured to commercializeproducts expected to have revolutionary impacts on a variety ofindustries, including materials, electronics, life sciences, andenergy.

There are three strategic components to Arrowhead's businessmodel:

-- Outsourced R&D Program: Arrowhead identifies patented or patent-pending technologies at universities or government labs and funds additional development of those technologies in exchange for exclusive rights to commercialize the resulting prototypes. Leveraging the resources and infrastructure of these institutions provides Arrowhead with a cost-effective development pipeline. Currently, Arrowhead is supporting efforts in drug discovery tools, stem cell technology and nanoelectronics at the California Institute of Technology, Stanford University and Duke University, respectively.

-- Commercialization Program: After prototypes have been sufficiently developed in the laboratories, Arrowhead forms or acquires majority-owned subsidiaries to commercialize the technology and provides the subsidiaries with strategic, managerial and operational support. By doing so, each research team is able to maintain focus on its specific technology and each management team can focus on specific markets, increasing the likelihood of successful technological development and commercialization. At present, Arrowhead owns majority interest in subsidiaries commercializing diverse technologies, including anti-cancer drugs, RNAi therapeutics, compound semiconductor materials and nanotube technology.

-- The Patent Toolbox: Arrowhead has acquired or exclusively licensed patents and patent applications covering a broad range of nanotechnology. The Company actively adds to its intellectual property portfolio.

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