Exhibit 99.1

(SERONO LOGO)                                                   (CANCERVAX LOGO)

FOR IMMEDIATE RELEASE

              CANCERVAX AND SERONO ANNOUNCE GLOBAL DEVELOPMENT AND
                COMMERCIALIZATION COLLABORATION FOR CANVAXIN(TM)

       CANVAXIN(TM) IN PHASE 3 CLINICAL TRIALS FOR ADVANCED-STAGE MELANOMA

CARLSBAD, CALIFORNIA AND GENEVA, SWITZERLAND - DECEMBER 16, 2004 - CancerVax
Corporation (NASDAQ: CNVX) and Serono (Virt-X: SEO and NYSE: SRA) announced
today a worldwide collaboration for the development and commercialization of
Canvaxin(TM), an investigational specific active immunotherapy product being
developed for the treatment of advanced-stage melanoma, a deadly form of skin
cancer. Canvaxin(TM) is currently being evaluated in two international,
multi-center Phase 3 clinical trials for the treatment of Stage III and Stage IV
melanoma.

Under the Agreement, CancerVax and Serono will jointly develop Canvaxin(TM) for
melanoma, as well as other indications. The companies will share equally the
costs of developing Canvaxin(TM) and seeking regulatory approvals for
Canvaxin(TM).

CancerVax and Serono will co-promote Canvaxin(TM) in the U.S. and share certain
expenses and profits on a 50/50 basis. Outside the U.S., Serono will have the
exclusive right to commercialize Canvaxin(TM) and will pay royalties to
CancerVax based on its sales of the product. Initially, CancerVax will
manufacture Canvaxin(TM) for supply throughout the world. Serono may eventually
establish a second manufacturing site for Canvaxin(TM), to supply primarily
markets outside the U.S.

CancerVax will receive an initial cash payment of $37 million, comprised of $25
million in upfront signing fees and $12 million for the purchase of 1 million
shares of CancerVax common stock. CancerVax could receive up to $253 million in
additional payments linked to the achievement of development, regulatory and
commercial milestones. The element of these milestone payments relating to the
receipt of regulatory approvals through to marketing Canvaxin(TM) solely in
Stage III and Stage IV melanoma in the U.S. and the EU could amount to $100
million.

"We are very enthusiastic about establishing this collaboration with Serono to
potentially bring Canvaxin(TM) to patients with advanced-stage melanoma around
the world," said David F. Hale, President & CEO of CancerVax Corporation. "By
partnering with Serono, a leading biotechnology company with significant
expertise in the development


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and commercialization of biological products, CancerVax has taken a major step
forward in achieving our goal of becoming a world leader in new therapies for
the treatment of cancer," said Hale.

"This collaboration with CancerVax is a major milestone in Serono's
establishment of a significant presence in the field of oncology, and further
demonstrates Serono's commitment to expanding our portfolio of innovative
clinical-stage projects which address significant, unmet medical needs," Ernesto
Bertarelli, CEO of Serono, said. Dermatologists have a significant role in the
diagnosis and treatment of melanoma in Europe and many other countries around
the world. The dermatology presence which Serono has established through the
recent launch of Raptiva for the treatment of moderate-to-severe psoriasis will
provide us with a significant operational asset on which to build for the
commercialization of Canvaxin(TM)."

ABOUT MELANOMA

According to the American Cancer Society, melanoma is the deadliest type of skin
cancer and is the sixth most commonly diagnosed cancer in the United States. As
reported by the World Health Organization the worldwide incidence, or number of
newly diagnosed cases, of melanoma in 2000 was 132,600, with 37,000 people dying
of the disease. Furthermore, according to the National Cancer Institute, since
1997 the incidence of new melanoma cases in the United States has increased at
an average rate of more than 5% per year, one of the highest growth rates for
any type of cancer. In 2000, over 510,000 patients in the United States were
living with melanoma. "Melanoma is one of the fastest growing types of cancers.
According to the American Cancer Society, an estimated 55,000 new cases will be
diagnosed in the United States in 2004, double the number from 30 years ago and
7,900 will die as a result of the disease," said Mary Loh, Executive Director of
the American Melanoma Foundation. "Prevention and early detection are the best
defenses against early-stage melanoma, but we desperately need new treatment
options for patients suffering with advanced stages of this disease."

ABOUT CANVAXIN(TM)

Canvaxin(TM), one of a new class of products being developed in the area of
specific active immunotherapy (SAI) or therapeutic cancer vaccines, is based on
a proprietary technology that may potentially be applied to treat a number of
cancers. Canvaxin(TM) is currently being evaluated in two international,
randomized, double-blind, placebo-controlled trials designed to evaluate the
ability of Canvaxin(TM) to extend the survival of patients with Stage III and
Stage IV melanoma following surgical resection of their tumors. In September
2004, CancerVax completed the planned enrollment of 1,118 patients into its
Phase 3 clinical trial of Canvaxin(TM) for the treatment of patients with Stage
III melanoma. CancerVax continues to make progress with the enrollment of
patients in the Stage IV clinical trial and is evaluating the potential for
Canvaxin(TM) in the treatment of other types of cancer.

ABOUT CANCERVAX CORPORATION (WWW.CANCERVAX.COM)

CancerVax Corporation is a biotechnology company focused on the research,
development and commercialization of novel biological products for the treatment
and control of cancer. The Company's lead product candidate, Canvaxin(TM), is
one of a new class of products being


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developed in the area of specific active immunotherapy, also known as
therapeutic cancer vaccines. Canvaxin(TM) is currently being studied in two
international Phase 3 clinical trials for the treatment of patients with Stage
III or Stage IV, or advanced-stage, melanoma. The Company is also finalizing the
design of exploratory Phase 2 clinical trials for patients with other
advanced-stage solid tumors. In addition to Canvaxin(TM), CancerVax has licensed
three specific active immunotherapeutic product candidates targeting the
epidermal growth factor receptor signaling pathway, including SAI-EGF, which has
been studied in Phase 2 clinical trials. The Company plans to identify and
develop new product candidates based on its proprietary specific active
immunotherapy, anti-angiogenesis and T-oligo, or telomere homolog
oligonucleotide, technology, as well as on its human monoclonal antibodies.
CancerVax's corporate headquarters and research and development facility is
located in Carlsbad, California, and its biologics manufacturing facility is
located in the Los Angeles area.

ABOUT SERONO

Serono is a global biotechnology leader. The Company has eight biotechnology
products, Rebif(R), Gonal-F(R), Luveris(R), Ovidrel(R)/Ovitrelle(R),
Serostim(R), Saizen(R), Zorbtive(TM) and Rapitva(R). In addition to being the
world leader in reproductive health, Serono has strong market positions in
neurology, metabolism and growth and has recently entered the psoriasis area.
The Company's research programs are focused on growing these businesses and on
establishing new therapeutic areas. Currently, there are approximately 30
ongoing development projects.

In 2003, Serono achieved worldwide revenues of US$2,018.6 million, and a net
income of US$390.0 million, making it the third largest biotech company in the
world. Its products are sold in over 90 countries. Bearer shares of Serono S.A.,
the holding company, are traded on the virt-x (SEO) and its American Depositary
Shares are traded on the New York Stock Exchange (SRA).

FORWARD-LOOKING STATEMENTS

CancerVax

CancerVax cautions you that statements included in this press release that are
not a description of historical facts are forward-looking statements. For
example, statements about future payments under the collaboration agreement, if
any, the manufacture of Canvaxin(TM) and plans and objectives of management are
all forward-looking statements. The inclusion of forward-looking statements
should not be regarded as a representation by CancerVax that any of its plans
will be achieved. Actual results may differ materially from those set forth in
this release due to the risks and uncertainties inherent in CancerVax's
business, including without limitation, statements about: the progress and
timing of the clinical trials of Canvaxin(TM); the potential that results of
Phase 1 and 2 clinical trials of Canvaxin(TM), which were evaluated using
retrospective survival analyses that may be subject to potential selection
biases, may not be predictive of future results of the ongoing Phase 3 clinical
trials; difficulties or delays in researching, developing, testing, obtaining
regulatory approval, producing and marketing Canvaxin(TM); unexpected adverse
side effects or inadequate therapeutic efficacy of Canvaxin(TM) that could delay
or prevent product development or commercialization, or that could result in
recalls or product liability claims; CancerVax's inability to protect its
intellectual property and proprietary technology and to maintain and enforce its
licensing arrangements with respect to Canvaxin(TM); the scope and validity of
patent protection for Canvaxin(TM); competition from other pharmaceutical or
biotechnology companies; CancerVax's limited experience in manufacturing and
testing biological products, which may result in delayed development or
commercialization of Canvaxin(TM), as well as lost revenue; the risk that the
collaboration agreement may be terminated by Serono in certain instances; and
other risks detailed in CancerVax's Securities and


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Exchange Commission filings, including CancerVax's Annual Report on Form 10-K
for the fiscal year ended December 31, 2003 and its Quarterly Report on Form
10-Q for the fiscal quarter ended September 30, 2004. You are cautioned not to
place undue reliance on these forward-looking statements, which speak only as of
the date hereof. All forward-looking statements are qualified in their entirety
by this cautionary statement and CancerVax undertakes no obligation to revise or
update this news release to reflect events or circumstances after the date
hereof. This caution is made under the safe harbor provisions of the Private
Securities Litigation Reform Act of 1995.

Serono

Some of the statements in this press release are forward looking. Such
statements are inherently subject to known and unknown risks, uncertainties and
other factors that may cause actual results, performance or achievements of
Serono S.A. and affiliates to be materially different from those expected or
anticipated in the forward-looking statements. Forward-looking statements are
based on Serono's current expectations and assumptions, which may be affected by
a number of factors, including those discussed in this press release and more
fully described in Serono's Annual Report on Form 20-F filed with the U.S.
Securities and Exchange Commission on March 25, 2004. These factors include any
failure or delay in Serono's ability to develop new products, any failure to
receive anticipated regulatory approvals, any problems in commercializing
current products as a result of competition or other factors, our ability to
obtain reimbursement coverage for our products, and government regulations
limiting our ability to sell our products. Serono has no responsibility to
update the forward-looking statements contained in this press release to reflect
events or circumstances occurring after the date of this press release.

CancerVax(R) is a registered trademark of CancerVax Corporation.
Canvaxin(TM) is a trademark of CancerVax Corporation.

FOR MORE INFORMATION, PLEASE CONTACT:

CANCERVAX CONTACT:

VINCE REARDON
CANCERVAX CORPORATION

SENIOR DIRECTOR, INVESTOR RELATIONS

+1 760-494-4850

SERONO IN GENEVA, SWITZERLAND:

 CORPORATE MEDIA RELATIONS:     CORPORATE INVESTOR RELATIONS:
 Tel:  +41 22 739 36 00         Tel:   +41 22 739 36 01
 Fax:  +41 22 739 30 85         Fax:   +41 22 739 30 22
 http://www.serono.com          Reuters: SEO.VX / SRA.N
                                Bloomberg: SEO VX / SRA US


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