PASADENA, Calif., February 2, 2012 - Arrowhead Research Corporation (NASDAQ:ARWR) today announced that it will report its financial results for the fiscal 2012 first quarter ended December 31, 2011, on Thursday, February 9, 2012 at 4:30 p.m. Eastern time (1:30 p.m. Pacific time). To participate in the conference call, please dial 877-317-6789 (toll free from the US and Canada), or 412-317-6789 (for international callers). Investors may also access a live audio webcast of this conference call on the Company's website at www.arrowheadresearch.com.

A replay of the webcast will be available approximately two hours after the conclusion of the call. The webcast archive will remain available for 90 days. An audio replay will also be available approximately two hours after the conclusion of the call and will be made available until Thursday, February 16, 2012. The audio replay can be accessed by dialing 877-344-7529 (toll free from the US and Canada), or 412-317-0088 (for international callers) and entering Event ID 10009858.

About Arrowhead Research Corporation

Arrowhead Research Corporation is a clinical stage nanomedicine company developing innovative therapies at the interface of biology and nanoengineering. Arrowhead's world-class capabilities and intellectual property covering nucleic acid delivery, siRNA chemistry, and tissue targeting allow it to design and develop therapeutic agents for a wide range of diseases. The company's lead products include CALAA-01, an oncology drug candidate based on the gene silencing RNA interference (RNAi) mechanism, and AdipotideTM, an anti-obesity peptide that targets and kills the blood vessels that feed white adipose tissue. Arrowhead is leveraging its proprietary Dynamic PolyConjugateTM (DPC), Liposomal Nanoparticle (LNP), and RONDELTM delivery platforms to support its own pipeline of preclinical and clinical candidates and to secure external partnerships and collaborations with biotech and pharmaceutical companies.www.arrowheadresearch.com.