Calando Pharmaceuticals to Present at 19th Annual Oppenheimer Healthcare Conference on November 4, 2008.

PASADENA, Calif. -- Calando Pharmaceuticals, Inc., a majority-owned subsidiary of Arrowhead Research Corporation (NASDAQ:ARWR), announced today that its CEO, Dr. James Hamilton, will present at the 19th Annual Oppenheimer Healthcare Conference on Tuesday, November 4, 2008 at 11:00am ET. The conference is being held at the Waldorf Astoria Hotel in New York City. Dr. Hamilton's presentation will discuss Calando's proprietary delivery systems for siRNA and small molecule drugs and Calando's clinical program for its two lead compounds, CALAA-01 and IT-101.

CALAA-01, currently undergoing a Phase I clinical trial, is believed to be the first siRNA therapeutic to enter the oncology clinic. To our knowledge, it is also the first systemically delivered siRNA therapeutic formulated with a targeted delivery system. Calando's RONDEL[TM] delivery system was developed to address the long-standing obstacle of effective delivery and targeting for this potentially revolutionary new class of pharmaceuticals. CALAA-01 is a targeted nanoparticle comprised of a patented, non-chemically-modified siRNA against the M2 subunit of ribonucleotide reductase, a clinically-validated cancer target and the RONDEL system.

IT-101, Calando's lead candidate delivering a small molecule drug, began clinical trials in 2006. IT-101 demonstrated safety and favorable pharmacokinetic properties in Phase I clinical trials and is currently undergoing a Phase II clinical trial. IT-101 is a conjugate of Cyclosert[TM], Calando's proprietary delivery system for small molecule drugs, and camptothecin. Both RONDEL[TM] and Cyclosert[TM] utilize modified cyclodextrin molecules to create an entirely new class of drug delivery materials, which Calando believes have the ability to solve many of the deficiencies observed in therapeutic product candidates.

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 and raise the necessary financing to fund our operations and research activities. 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.