Rebif (Interferon Beta 1a)
Appears More Effective Than Avonex
(Interferon Beta 1a) In Treating Multiple Sclerosis

GENEVA, SWITZERLAND -- May 8, 2001 -- Serono announced today the
major outcomes of the direct comparative study between Rebif® and
Avonex® in patients with relapsing-remitting multiple sclerosis
(RRMS). The primary endpoint of the study shows that patients treated
with Rebif have a 90 percent greater chance of remaining relapse-free
during the period of observation compared to patients treated with
Avonex. This result is highly statistically significant with a p
value of 0.0005.

"We are pleased that the study endpoints as agreed with the FDA have
been achieved. We will now progress our discussions with the Agency
in our effort to make Rebif available to patients in the USA as soon
as possible," said Ernesto Bertarelli, Chief Executive Officer of
Serono.

The EVIDENCE (EVidence for Interferon Dose-effect: European-North
American Comparative Efficacy) study is of particular interest as it
marks the largest prospective comparative study of two disease
modifying drugs in multiple sclerosis (MS).

The objective of the study was to demonstrate the clinical benefit of
Rebif compared to Avonex based on pre-defined FDA approved endpoints.
The study was conducted with the concurrence of the FDA regarding its
design, primary and secondary endpoints and the prospectively defined
statistical analysis plan. It measured clinical endpoints as well as
brain scan endpoints using magnetic resonance imaging (MRI).

The primary endpoint of the study is a comparison of the proportion
of relapse-free patients after 24 weeks, expressed as an adjusted
odds ratio. The resulting ratio is 1.9. This means that patients
treated with Rebif have a 90 percent greater chance of remaining
relapse-free during the period of observation compared to patients
treated with Avonex. This result is highly statistically significant
with a p value of 0.0005. This finding is based on a 32 percent
relative reduction in the proportion of patients experiencing
relapses on Rebif as compared to Avonex.

The main secondary endpoint is the reduction in combined unique
lesion activity as measured by MRI over 24 weeks. Patients treated
with Avonex had 50 percent more new lesions in the brain than those
treated with Rebif. This result is also highly statistically
significant with a p value less than 0.0001.

Included in the EVIDENCE Study were 677 patients with RRMS at 56
centers in nine countries in North America and Europe. Patients
underwent repeated clinical and MRI assessments while taking either
Rebif (interferon beta-1a) 44 mcg three times weekly or Avonex
(interferon beta-1a) 30 mcg once weekly. During the study, all
assessing neurologists and radiologists were blinded from knowing
which drug the patients were taking. The primary and main secondary
endpoints are at 24 weeks, and both these endpoints have been
achieved. The study follows patients for a total of 48 weeks.

Further details of the data on all endpoints of the EVIDENCE study
will be announced on June 22 at a platform presentation during the
World Congress of Neurology in London.

Rebif cannot currently be marketed in the USA. The Orphan Drug status
of Avonex is due to expire in mid 2003.

The terms of the Orphan Drug Act permit Rebif to potentially enter
the USA market before mid 2003, if Rebif has been compared in a
direct head-to-head study in order to demonstrate its clinical
benefit over Avonex based on pre-defined endpoints. The pre-defined
endpoints agreed with the FDA were:

· Primary = The proportion of relapse-free patients after 24
weeks,
expressed as an adjusted odds ratio.
· Main Secondary = The reduction in combined unique lesion
activity
as measured by MRI over 24 weeks.

The results of this study will be submitted to the Food and Drug
Administration (FDA), as part of Serono's ongoing discussions with
the Agency.


SOURCE: Serono International S.A.

Early, High-Dose Rebif (Interferon Beta-1a) Slows MS Progression

NORWELL, MA -- March 23, 2000 -- New data from the largest and most comprehensive controlled long-term study in patients with relapsing- remitting multiple sclerosis (RRMS) using Rebif(R), an interferon beta-1a product, points to continued benefit of Rebif(R) 22 mcg and Rebif(R) 44 mcg administered three times weekly for four years. Preliminary analysis of the Prisms four year data report a dose-effect relationship on clinical as well as MRI parameters with high dose Rebif(R) 3 x 44 mcg being superior to 3x22 mcg. In addition, the data also suggest that early treatment is better than delayed treatment. Together, the data support the benefit of early treatment and treatment with the highest tolerated dose in order to gain maximum benefit and slow disease progression. Rebif(R) was well-tolerated long-term and side effects were typical of interferon use and were generally mild in severity.

The Prisms study began in 1994, involving 560 patients at 22 centers in nine countries. Two year data published in 1998 reported that both Rebif(R) 3 x 22 mcg and Rebif(R) 3 x 44 mcg per week significantly reduced the number and severity of relapses, delayed disability progression and reduced disease activity and burden of disease as measured in magnetic resonance imaging (MRI). The new data are from the extension phase of this study up to four years. Over 90 percent (506) of the originally enrolled patients entered the extension phase and the vast majority of these completed the full four years. The objectives of the extension phase included the assessment of long-term benefits on the frequency of relapses, delay of disability progression, changes in MRI activity and burden of disease, dose-response and the benefit of early versus late therapy onset.

"This is very important data and good news for the multiple sclerosis community. The study was the best designed of any of the trials conducted with interferon in relapsing-remitting multiple sclerosis to date and offers the longest controlled follow-up", comments Mark Freedman, MD, Director of the Multiple Sclerosis Clinic at Ottawa Hospital, General Campus, and Associate Professor of Medicine (Neurology) at the University of Ottawa, an investigator in the Prisms trial. "It clearly indicates that beta-interferon can dramatically modify the natural course of the disease over four years, an effect that will hopefully continue for even longer. It also reinforces the need to treat as early as possible with the highest tolerable dose."

The detailed Prisms data will be released to the public at an upcoming major neurological conference. Rebif(R) is produced and marketed by Ares- Serono and is available in 50 countries worldwide, including Canada, Switzerland, the countries of the European Union, and many in Latin America. However, Rebif(R) is not on the market in the U.S. where Avonex(R) and Betaseron(R) are currently protected from competition under the Orphan Drug Act, a law that offers companies incentives to develop innovative treatments for rare conditions. The Act does allow approval of additional drugs that can clinically demonstrate either safety or efficacy advantages or constitute a major contribution to patient care. Ares-Serono launched a comparative study of Rebif(R) versus Avonex(R) in the second half of 1999. The trial of over 600 patients with RRMS compares a 132 mcg weekly subcutaneous dose of Rebif(R) (44 mcg three times per week), to a 30 mcg per week intramuscularly dose of Avonex(R) to determine if Rebif(R)'s higher-dose formulation offers efficacy advantages.

An estimated one to two million people worldwide are living with multiple sclerosis, which is a chronic, debilitating disease of the central nervous system that affects mainly young adults. At present, most patients with MS will become increasingly disabled, but data from trials such as Prisms suggest that therapies such as Rebif(R) may beneficially affect the progression of MS.

Ares-Serono, headquartered in Geneva, Switzerland, is a global leader in biotechnology with its U.S. affiliate, Serono Laboratories, Inc., based in Norwell, Massachusetts. In addition to being the world leader in reproductive health with the leading infertility product, Gonal-F(R), Ares-Serono has strong global market positions in HIV-related metabolism (Serostim(R)) and growth (Saizen(R)). Outside of the U.S., the company markets a high-dose interferon beta-1a product for multiple sclerosis, called Rebif (R). The company's research programs, which include major R&D operations in the U.S., are focused on growing its existing businesses and on establishing new therapeutic areas. In 1999, Ares-Serono achieved worldwide sales of $1.054 billion, of which one-third were generated in North America. The company operates in 45 countries, and its products are sold in over 100 countries.