Isis Highlights New Clinical Data on Anti-Cancer Antisense Drugs Featured at ASCO

Isis Highlights New Clinical Data on Anti-Cancer Antisense Drugs Featured at
ASCO

ORLANDO, Fla. and CARLSBAD, Calif., June 1 /PRNewswire-FirstCall/ -- Isis
Pharmaceuticals, Inc. (Nasdaq: ISIS) announced today that Isis' collaborators
presented new clinical data on drugs in Isis' partnered oncology franchise at
this year's American Society of Clinical Oncology (ASCO) Annual Meeting in
Orlando, Florida. In total, four presentations were featured on three drugs
in Isis' oncology pipeline, including results from a Phase 2 study of OGX-011
in patients with advanced metastatic prostate cancer and Phase 1 study of
OGX-427 in patients with a variety of cancers. OGX-011 and OGX-427 are
antisense drugs co-discovered by Isis and OncoGenex (Nasdaq: OGXI) and Isis
licensed its rights to OGX-011 to OncoGenex Pharmaceuticals, Inc. In
addition, new results from a Phase 1 trial evaluating LY2181308, an antisense
drug discovered by Isis and licensed to Eli Lilly and Company, in patients
with cancer were also presented. Both Lilly and OncoGenex are also developing
additional anti-cancer drugs in Isis' oncology franchise.

"Oncology is one of the many different therapeutic applications of our
technology. Our drug discovery platform offers us virtually unlimited
opportunities to expand the scope of diseases we can treat with antisense
drugs," said Brett Monia, Ph.D., Vice President of Drug Discovery and
Corporate Development at Isis Pharmaceuticals. "We are encouraged by the
progress our partners are making with the four anti-cancer drugs in our
pipeline. The positive data our partners have reported plus the exciting work
from our research efforts on new anti-cancer targets have compelled us to
reinvigorate our internal cancer program. We expect to have exciting new
cancer drugs to enter development in the next 12 to 18 months."

On Saturday, May 30, Dr. Kim Nguyen Chi, principle investigator and a medical
oncologist at BC Cancer Agency - Vancouver Centre, presented the final results
of a randomized Phase 2 trial of OGX-011 in patients with advanced metastatic
prostate cancer. In this trial, OncoGenex reported that a median overall
survival was observed in patients treated with OGX-011 plus docetaxel of 23.8
months compared to 16.9 months for patients treated with docetaxel alone, the
current standard of care for patients with advanced metastatic prostate
cancer. In addition, OncoGenex reported that the unadjusted hazard ratio, a
measure used to determine the difference in survival between treatment groups
was 0.61, representing a 39% reduction in the rate of death for patients
treated with OGX-011. OGX-011 continues to be well tolerated in combination
with docetaxel. Based on clinical results to date, OncoGenex has said that it
intends to conduct Phase 3 registration trials with OGX-011 in metastatic
castrate resistant prostate cancer, subject to securing a development partner
or the receipt of additional funding.

Dr. Sebastien Hotte, principle investigator and medical oncologist at
Juravinski Cancer Centre, Hamilton, Ontario, presented new data on Saturday
May 30 from a Phase 1 study on OGX-427 in patients with a variety of cancers.
In this study, Dr. Hotte reported declines in circulating tumor cells at all
doses evaluated as well as evidence of reduction in tumor markers defined as
declines of PSA levels in prostate cancer or CA-125 levels in ovarian cancer.
For further details on both the OGX-011 and OGX-427 study results, please see
OncoGenex' releases that were issued on Saturday May 30, 2009.

Also on Saturday May 30, Dr. Denis Talbot, clinical investigator and medical
oncologist in the Medical Oncology Unit at The Churchill Hospital, Oxford
Radcliffe Hospitals NHS Trust, presented new data from a Phase 1 study of
LY2181308 in patients with cancer. The new data confirmed that LY2181308
penetrates tumor tissue and reduces survivin mRNA and protein levels in tumor
cells. In addition, Dr. Azeem Saleem, CRUK Senior Clinical Research Fellow,
University of Manchester, presented results of a pharmacokinetic study of
LY2181308 in patients with cancer. Using state-of-the-art imaging techniques
to assess radiolabeled LY2181308 distribution in humans, Dr. Saleem reported
that LY2181308 effectively penetrated tumor tissues. LY2181308 is currently
being evaluated in two separate Phase 2 studies in patients with relapsed or
refractory acute myeloid leukemia, and as a combination therapy in patients
with hormone refractory prostate cancer.

Information in this press release is based upon data reported by Isis' drug
development partners. Isis has not independently reviewed the clinical
results described in this release, but has relied in its partner's statements
entirely.

ABOUT ISIS PHARMACEUTICALS, INC.
Isis is exploiting its expertise in RNA to discover and develop novel drugs
for its product pipeline and for its partners. The Company has successfully
commercialized the world's first antisense drug and has 19 drugs in
development. Isis' drug development programs are focused on treating
cardiovascular and metabolic diseases. Isis' partners are developing
antisense drugs invented by Isis to treat a wide variety of diseases. Isis
and Alnylam Pharmaceuticals are joint owners of Regulus Therapeutics Inc., a
company focused on the discovery, development and commercialization of
microRNA therapeutics. Isis also has made significant innovations beyond
human therapeutics resulting in products that other companies, including
Abbott, are commercializing. As an innovator in RNA-based drug discovery and
development, Isis is the owner or exclusive licensee of over 1,600 issued
patents worldwide. Additional information about Isis is available at
www.isispharm.com.

This press release includes forward-looking statements regarding Isis'
business, its drug discovery and development pipeline, and the therapeutic
potential of antisense drugs for the treatment of cancer. Any statement
describing Isis' goals, expectations, financial or other projections,
intentions or beliefs is a forward-looking statement and should be considered
an at-risk statement. Such statements are subject to certain risks and
uncertainties, particularly those inherent in the process of discovering,
developing and commercializing drugs that are safe and effective for use as
human therapeutics, and in the endeavor of building a business around such
products. Isis' forward-looking statements also involve assumptions that, if
they never materialize or prove correct, could cause its results to differ
materially from those expressed or implied by such forward-looking statements.
Although Isis' forward-looking statements reflect the good faith judgment of
its management, these statements are based only on facts and factors currently
known by Isis. As a result, you are cautioned not to rely on these
forward-looking statements. These and other risks concerning Isis' programs
are described in additional detail in Isis' annual report on Form 10-K for the
year ended December 31, 2008, and its most recent quarterly report on Form
10-Q, which are on file with the SEC. Copies of these and other documents are
available from the Company.

In this press release, unless the context requires otherwise, "Isis,"
"Company," "we," "our," and "us" refers to Isis Pharmaceuticals and its
subsidiaries, including Regulus Therapeutics Inc.

Isis Pharmaceuticals is a registered trademark of Isis Pharmaceuticals, Inc.
Regulus Therapeutics is a trademark of Regulus Therapeutics Inc.

SOURCE Isis Pharmaceuticals, Inc.

Amy Blackley, Ph.D., Assistant Director, Corporate Communications,
+1-760-603-2772, or Kristina Lemonidis, Director, Investor Relations,
+1-760-603-2490, both of Isis Pharmaceuticals, Inc.