Nanotechnology Now - Press Release: Arrowhead subsidiary Calando Pharmaceuticals publishes study showing anti-cancer effect with lead RNAi candidiate

Home > Press > Arrowhead subsidiary Calando Pharmaceuticals publishes study showing anti-cancer effect with lead RNAi candidiate

Abstract:
Arrowhead Research Corporation (NASDAQ: ARWR) announced the publication by its majority-owned
subsidiary Calando Pharmaceuticals, Inc. of a study demonstrating the anti-proliferative effect of the siRNA sequence selected as the therapeutic component of its lead anti-cancer compound, CALAA-01.

Arrowhead subsidiary Calando Pharmaceuticals publishes study showing anti-cancer effect with lead RNAi candidiate

Pasadena, CA | Posted on April 3rd, 2007

The paper, entitled "Potent siRNA Inhibitors of Ribonucleotide
Reductase Subunit RRM2 Reduce Cell Proliferation In vitro and In
vivo", was published in Clinical Cancer Research, a journal published
by the American Association of Cancer Research (AACR). This paper
describes how Calando's proprietary siRNA duplex demonstrated
silencing of the target gene, RRM2, and reduced cell proliferation
across multiple species and cancer types, both in cell culture and in
whole animals. These findings confirm that this duplex is a promising
candidate for therapeutic development.

"The paper reports some of the great progress being made at Calando,"
said R. Bruce Stewart, Chairman and CEO of Arrowhead. "We believe
that siRNA will be one of the corner stones of cancer treatment in
the future".

"These studies demonstrate the potential for this siRNA duplex to
have a strong anti-tumor effect," said John Petrovich, Calando's
Chief Executive Officer. He further added that that Calando has filed
for patent protection on several siRNA duplexes against the RRM2
target and has licensed patents from Alnylam Pharmaceuticals to
enable it to develop and commercialize an RNAi therapeutic against
this target.

Further information about Calando can be found at
www.calandopharma.com.

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About Arrowhead Research Corporation
Arrowhead Research Corporation ( http://www.arrowheadresearch.com ) is a
publicly-traded nanotechnology company commercializing new
technologies in the areas of life sciences, electronics, and energy.
Arrowhead is building value for shareholders through the progress of
majority owned subsidiaries founded on nanotechnologies originally
developed at universities. The company works closely with
universities to source early stage deals and to generate rights to
intellectual property covering promising new nanotechnologies.
Currently, Arrowhead has four subsidiaries commercializing nanotech
products and applications, including anti-cancer drugs, RNAi
therapeutics, carbon-based electronics and compound semiconductor
materials.

About Calando Pharmaceuticals Inc.

Calando Pharmaceuticals Inc. ( http://www.calandopharma.com ), a majority
owned subsidiary of Arrowhead Research Corporation (NASDAQ: ARWR), is
using its proprietary technologies in targeted polymeric delivery
systems and siRNA design to design and create new, targeted siRNA
therapeutics. The company is pursuing this goal through its internal
research and development and also through collaborations and
partnerships with pharmaceutical and biotechnology companies.

Calando Technology

Calando's cyclodextrin-containing polymers 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 of
approximately 50-80 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. In
addition to targeting tumors, the targeting of liver cells has also
been accomplished in vivo.

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Act of 1995

This news release contains forward-looking statements within the
meaning ofthe "safe harbor" provisions of the Private Securities
Litigation Reform Actof 1995. These statements are based upon our
current expectations and speak onlyas of the date hereof. Our actual
results may differ materially and adversely from those expressed in
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uncertainties, including the recent economic slowdown affecting
technology companies, the future success of our scientific studies,
our ability to successfully develop products, rapid technological
change in our markets, changes in demand for our future products,
legislative, regulatory and competitive developments and general
economic conditions. Our Annual Report on Form 10-K and 10-K/A,
recent and forthcoming Quarterly Reports on Form 10-Q and 10-Q/A,
recent Current Reports on Forms 8-K and 8-K/A, our Registration
Statement on Form S-3, and other SEC filingsdiscuss some of the
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