Arrowhead to Present at Upcoming Conferences

PASADENA, Calif. — October 18, 2013 — Arrowhead Research Corporation (NASDAQ: ARWR), a biopharmaceutical company developing targeted RNAi therapeutics, today announced that it will present data on ARC-520, its hepatitis B drug candidate, at two upcoming scientific conferences.

Scheduled conference presentations include the following:

2013 International Meeting on Molecular Biology of Hepatitis B Viruses – Shangai, China, October 20-23, 2013

October 23, 2013 – A poster presentation titled, “Kinetics of knockdown from RNAi therapeutic ARC-520 on hepatitis B virus RNA, DNA, S antigen and e antigen in mice and chimpanzee,” will be presented by Christine Wooddell, Ph.D., Senior Scientist;

AASLD – The Liver Meeting – Washington, DC, USA, November 1-5, 2013

November 3, 2013 – A poster presentation titled, “ARC-520 RNAi therapeutic reduces HBV DNA, S and e antigen in a chimpanzee,” will be presented by Robert E. Lanford, Ph.D., Texas Biomedical Research Institute.

About Arrowhead Research Corporation

Arrowhead Research Corporation is a biopharmaceutical company developing targeted RNAi therapeutics. The company is leveraging its proprietary drug delivery technologies to develop targeted drugs based on the RNA interference mechanism that efficiently silence disease-causing genes. Arrowhead technologies also enable partners to create peptide-drug conjugates that specifically home to cell types of interest while sparing off-target tissues. Arrowhead’s pipeline includes clinical programs in chronic hepatitis B virus and obesity and partner-based programs in oncology.

For more information please visit http://www.arrowheadresearch.com, or follow us on Twitter @ArrowRes. To be added to the Company’s email list to receive news directly, please send an email to ir@arrowres.com