MEDIMMUNE LICENSES CATALYTIC ANTIBODY TO TREAT COCAINE OVERDOSE AND ADDICTIon

GAITHERSBURG, Md., Sept. 15 /PRNewswire/ -- MedImmune, Inc. (Nasdaq: MEDI)
today announced that it has entered into an exclusive licensing agreement
and a research collaboration with Columbia University to develop and
commercialize a catalytic antibody against cocaine to treat overdose and
addiction. Under the terms of the agreements, MedImmune will be responsible
for worldwide research, clinical development, manufacturing and
commercialization of any product resulting from the collaboration. MedImmune
will pay a one-time license fee to Columbia, and will make milestone and
royalty payments based on clinical development progress and sales of
resulting products. Ixsys, Inc. will optimize the primary product candidate
as part of the four-product antibody alliance the company entered into with
MedImmune in February 1999.

"The challenge of treating cocaine addiction with specific antibodies is to
maintain a circulating therapeutic level of the antibody as the cocaine
target is depleted," commented Scott Koenig, M.D., Ph.D., Senior Vice
President of Research at MedImmune. "We believe that catalytic antibodies,
which both bind and degrade the target, and free the antibody to bind to
additional cocaine molecules, may provide the solution to that problem. A
product with these characteristics may prove to be a possible option to
treat cocaine overdoses or as an aid to breaking cocaine addiction."

Cocaine specifically blocks the reuptake of several neurotransmitters in the
brain including dopamine, which is associated with emotional response,
movement and the ability to experience pleasure. The drug binds to dopamine
receptors in the brain, which blocks reabsorption and increases both the
amount of dopamine and the number of receptors in the brain. This
artificially induced increase in levels of dopamine causes increased
activation in the brain's pleasure center, causing euphoria. Addiction
occurs with continued use of cocaine, as the brain can no longer respond to
natural reward stimulation and is forced to rely on the drug to maintain the
artificial high. At the extremely high concentrations seen in drug overdose,
the drug binds to multiple receptors in the nervous system and the
cardiovascular system, possibly causing arrhythmia and sudden death. MAb
15A10, a catalytic antibody, has been shown to bind, cleave and release the
degraded cocaine in vitro, thus freeing itself for further cocaine binding.
Additionally, the antibody has been shown to block the reinforcing effects
of cocaine and provide protection from cocaine-induced seizures and sudden
death in animal models. "Our work to date with 15A10 has demonstrated the
antibody's ability to catalyze free cocaine in an animal model," added
Donald W. Landry, M.D., Associate Professor of Medicine and Director of
Clinical Pharmacology and Experimental Therapeutics at the Columbia
University College of Physicians and Surgeons Department of Medicine. "We
believe that this new collaboration with MedImmune will allow both parties
to further develop this antibody as possible therapy for recovering addicts
or as treatment for cocaine overdose. Cocaine abuse is a serious problem,
both in the U.S. and abroad, and we are excited about the opportunity to
collaborate with MedImmune to address this issue."

Since 1980, over 40,000,000 Americans have used cocaine or crack, the street
name given to cocaine processed to a free base for smoking. An estimated 2
million people are addicted to cocaine, and there are over four million
estimated regular users of the drug. Cocaine overdose is the most frequent
cause of addiction related emergency room admissions in the U.S. and Europe,
with approximately 150,000 and 100,000 admissions, respectively, in 1998. A
1998 survey funded by the National Institute on Drug Abuse found that the
rate of current cocaine use in 1996 was highest in the 18 to 25 age group
(2.0 percent). The rate of use for this age group was significantly higher
in 1996 than in 1995, when it was 1.3 percent. The same survey found that
the proportion of high-school seniors who have used cocaine at least once in
their lifetimes has increased from a low of 5.9 percent in 1994 to 8.7
percent in 1997. The Physician Leadership on National Drug Policy,
addressing the potential cost benefit of treatment, recently reported that
approximately seven dollars is saved in medical and societal costs for every
dollar spent on treatment of addiction. Current treatment options for
cocaine addiction are limited and include treatment medications and
behavioral interventions, including cognitive behavioral therapy.

MedImmune, located in Gaithersburg, Maryland, is a biotechnology company
focused on developing and marketing products that address medical needs in
areas such as infectious disease, transplantation medicine, autoimmune
disorders and cancer. MedImmune markets three products through its
hospital-based sales force and has five new product candidates in clinical
trials.

This announcement may contain, in addition to historical information,
certain forward-looking statements that involve risks and uncertainties.
Such statements reflect management's current views and are based on certain
assumptions. Actual results could differ materially from those currently
anticipated as a result of a number of factors, including risks and
uncertainties discussed in the Company's filings with the U.S. Securities
and Exchange Commission.