Calando Pharmaceuticals Collaborates with City of Hope to Initiate Investigator Sponsored Clinical Trial Using IT-101 in Lymphoma Patients.

PASADENA, Calif. -- Calando Pharmaceuticals, a majority-owned subsidiary of Arrowhead Research Corporation (NASDAQ:ARWR), announced today that it has entered into a collaboration with City of Hope in Duarte, CA to initiate an investigator sponsored clinical trial using Calando's nanoparticle drug candidate, IT-101, in patients with various forms of lymphoma.

The trial will be an open-label, phase II study of IT-101 intended to demonstrate safety and efficacy in patients with relapsed or refractory lymphoma, and will be preceded by a brief dose finding run-in phase. Patients with relapsed or refractory lymphoma, including B cell, T cell, and Hodgkin Lymphoma who satisfy eligibility requirements will be considered for admission to the trial.

"This is a very important and exciting trial to determine the efficacy and tolerability of a rationally designed and novel nanotechnology based drug delivery system of a cancer chemotherapeutic drug, with impressive preclinical activity in lymphoma," said lead investigator, Stephen Forman, M.D., Chair, Division of Hematology & Hematopoietic Cell Transplantation at City of Hope.

"We are very pleased to be working with Dr. Forman and City of Hope on this study," said James Hamilton, M.D., CEO of Calando Pharmaceuticals. "This represents an excellent opportunity to leverage the IT-101 franchise into additional oncology indications, while minimizing clinical development costs."

IT-101, a drug conjugate of camptothecin and Calando's proprietary cyclodextrin polymer nanoparticle, Cyclosert, has demonstrated a highly favorable toxicity profile and unique pharmacokinetic characteristics. Calando has recently completed enrollment of an ongoing phase I study of IT-101 at City of Hope for patients with non-resectable solid tumors and has filed with the FDA to initiate a multi-site phase II clinical trial of IT-101 in patients with ovarian cancer.

About Calando Pharmaceuticals Inc.

Calando Pharmaceuticals Inc. (www.calandopharma.com), a majority-owned subsidiary of Arrowhead Research Corporation (NASDAQ:ARWR), is a biopharmaceuticals company using proprietary technologies developed at Caltech to create targeted siRNA-based therapeutics and small molecule nanoparticle drug conjugates. Calando uses its innovative Cyclosert[TM] and RONDEL[TM] nanoparticle systems to solve the long-standing obstacle of effective delivery and targeting for oligonucleotide and small molecule therapeutics.

Calando's Cyclosert[TM] technology uses cyclodextrins as building blocks to create an entirely new class of biocompatible materials - linear cyclodextrin-containing polymers that are non-toxic and non-immunogenic at therapeutic doses. The Company leverages Cyclosert[TM] to design, develop and commercialize drug-delivery-enhanced small-molecule therapeutics. IT-101 is Calando's lead small molecule Cyclosert conjugate, which recently completed a phase I study in solid tumors at City of Hope.

Calando's RONDEL[TM] technology involves the use of cyclodextrin-containing polymers that form the foundation for its two-part siRNA delivery system. The first component is a linear, cyclodextrin-containing polycation that, when mixed with small interfering RNA (siRNA), binds to the anionic "backbone" of the siRNA. The polymer and siRNA self-assemble into nanoparticles smaller than 100 nm in diameter that fully protect the siRNA from nuclease degradation in serum. The siRNA delivery system has been designed to allow for intravenous injection. Upon delivery to the target cell, the targeting ligand binds to membrane receptors on the cell surface and the RNA-containing nanoparticle is taken into the cell by endocytosis. There, chemistry built into the polymer functions to unpackage the siRNA from the delivery vehicle. Based upon this breakthrough in siRNA delivery enabled by the RONDEL[TM] system, the promise of using siRNA in new systemic therapies may finally be realized.

Forward-Looking Statements

This news release and any oral statements made with respect to the information contained in this news release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include statements which express plans, anticipation, intent, contingency, goals, targets, future development and are otherwise not statements of historical fact. These statements are based on Calando's management current expectations and are subject to risks and uncertainties that could cause actual results or developments to be materially different from historical results or from any future results expressed or implied by such forward-looking statements. Factors that may cause actual results or developments to differ materially include, among others: the risk that CALAA-01 or IT-101 may appear promising in early research and clinical trials but may not demonstrate safety and/or efficacy in larger-scale or later stage clinical trials, the risks that the regulatory approvals may not be obtained, the risks associated with dependence upon key personnel, the risks associated with reliance on collaborative partners and others for further clinical trials, development, manufacturing and commercialization of our product candidates; the cost, delays and uncertainties associated with our scientific research, product development, clinical trials and regulatory approval process; our history of operating losses since our inception; competition; litigation; and risks associated with our ability to protect our intellectual property. You are cautioned not to place undue reliance on any forward-looking statements, any of which could turn out to be wrong due to inaccurate assumptions, unknown risks or uncertainties or other risk factors.