Basel, July 15  - FUZEON (enfuvirtide, formerly known as T-20), the first drug to block the HIV virus from entering the human immune cell, is revolutionizing the treatment options for pre-treated HIV patients, giving them new hope for longer and better lives.

Unprecedented results World experts at the International AIDS Society (IAS), the largest international AIDS conference for 15 years to be held in France, heard today how the better than expected 24 and 48-week TORO (T-20 vs Optimized Regimen Only) 1 and TORO 2 data has confirmed that FUZEON used with an optimized regimen of available HIV medication outperformed combinations comprised of the optimized regimen without FUZEON. Patients taking FUZEON as part of their drug combination were twice as likely to achieve undetectable levels of HIV and even doubled their immune cell count increase versus those who did not take FUZEON.

Greatest magnitude of benefit when FUZEON is used earlier

The FUZEON containing regimen provided benefits across all sub-groups examined including patients with few or no other treatment options. However, further analyses demonstrate that in the TORO study population at 24 weeks, the greatest magnitude of benefit is achieved when FUZEON is used earlier[1] in treatment rather than later¹ or when patients have a higher CD4 count (�100 versus �100 cells/mm³).

Durability of response confirmed

The 48-week data from the TORO 1 and 2 studies show that the treatment benefit provided by FUZEON is maintained over longer term therapy in pre-treated patients. In addition, the duration of benefit was three times longer for patients taking a FUZEON containing regimen than for those taking the optimized regimen without FUZEON.

David Cooper, Professor of Medicine, University of New South Wales said: �The magnitude of benefit obtained by patients taking FUZEON at 24 weeks, together with the long term maintenance of benefits was remarkable, particularly given the high previous exposure to HIV medications in the patient population. The benefit from the FUZEON based regimen was greatest when used earlier, when there were a greater number of active agents to combine with FUZEON.�

James Locke, a person who has been living with HIV for 18 years commented: �I have now been taking FUZEON for well over two years and still my HIV remains undetectable. FUZEON has given me back my hopes and dreams and I am now once again able to plan my future.�

2003 � The year of FUZEON

The year 2003 marks the 20^th anniversary of the discovery of the HIV virus and the approval of FUZEON in Europe and the US, heralding the start of a new era in the treatment of HIV. Developed by Roche and Trimeris Inc., FUZEON is the first in a new class of anti-HIV medication, known as �fusion inhibitors�, and represents the first new class of HIV therapy to be approved since 1996. FUZEON attacks HIV in a totally different way, compared to existing HIV medications, by blocking the fusion of HIV with human immune cells while existing drugs act once the cell is infected. As a result of the very different mechanism of action, FUZEON is active against HIV strains that have become resistant to current therapies.

Drug supply exceeds expectations

FUZEON is one of the most structurally complex and challenging molecules ever chemically manufactured by the pharmaceutical industry at large scale, requiring more than 100 production steps. Mr. Charles Sabbah, Head of Roche Global Strategic Marketing commented: �We are now able to supply FUZEON for up to 18,000 patients by the end of the year, a significant increase over the 12-15,000 patients originally estimated. This is because supply output is continuing to steadily increase and is greater than we had projected for this point in time.� Mr Sabbah added: �Physicians should now have a far greater level of confidence that they can prescribe FUZEON for those patients who will benefit from the drug and that their patients will gain access to this breakthrough medication.�

- Ends -

Notes to Editors:

1.       Study Design

TORO 1 (T-20 vs. Optimised Regimen Only) and TORO 2 are randomised, open-label trials that enrolled approximately 1,000 patients at 112 centres internationally. Patients in the trials were treatment-experienced and/or had documented resistance to each of the three classes of currently available antiretrovirals.  In addition, each patient was required to have a HIV level of greater than 5,000 copies/mL.

At entry, genotypic and phenotypic resistance testing was used to aid in the selection of an antiretroviral regimen, consisting of three to five drugs, including if appropriate, up to two newly approved or investigational drugs.  After selection of the regimen, patients were randomised 2:1 to receive either the regimen in combination with FUZEON or the regimen alone.  Patients randomized to FUZEON receive FUZEON administered as one 90 mg subcutaneous self-injection twice-daily.

2.       Safety of FUZEON 

FUZEON is administered as a twice-daily subcutaneous injection.  Local injection site reactions were the most frequent adverse events associated with the use of FUZEON.  In the TORO studies, 98 percent of patients had at least one local injection site reaction over the course of 48 weeks.  In this treatment-experienced patient population, 4 percent of patients at 48 weeks discontinued treatment with FUZEON as a result of injection site reactions.

An increased rate of some bacterial infections, primarily pneumonia, was seen in patients treated with FUZEON.  It is unclear if this increased incidence is related to FUZEON use.  The addition of FUZEON to background antiretroviral therapy generally did not increase the frequency or the severity of the majority of adverse reactions.  The majority of adverse reactions were of mild or moderate intensity.  Hypersensitivity reactions have occasionally been associated with FUZEON therapy and in rare cases have recurred on re-challenge.

3.       FUZEON indication in the European Union

The indication for FUZEON in the European Union is for �use in combination with other antiretroviral medicinal products for the treatment of HIV-1 infected patients who have received treatment with and failed on regimens containing at least one medicinal product from each of the following antiretroviral classes, protease inhibitors, non-nucleoside reverse transcriptase inhibitors and nucleoside reverse transcriptase inhibitors, or who have intolerance to previous antiretroviral regimens. In deciding on a new regimen for patients who have failed an antiretroviral regimen, careful consideration should be given to the treatment history of the individual patient and the patterns of mutations associated with different medicinal products. Where available, resistance testing may be appropriate.�

Resistance to HIV drugs

It is estimated that in a single untreated person the virus can mutate to form around a billion new and potentially different versions of HIV every day. The incidence of drug resistant HIV among already treated patients is increasing at a disturbing rate. It was recently reported in one study that up to 50 percent of patients in North America are infected with a strain of the virus that has developed resistance to one or more anti-HIV drug.

Roche in HIV

Roche is at the forefront of efforts to combat HIV infection and AIDS, committed since 1986 to groundbreaking research and development of innovative new drugs and diagnostic technology. Saquinavir was the first Protease Inhibitor (PI) and was first introduced by Roche in 1995 in the US.

As a consequence of Roche's continuous research and development, the combination of boosted saquinavir with ritonavir (1000/100 mg twice daily) has shown encouraging results in the MaxCmin 1 trial with high efficacy and an excellent safety and tolerability profile.

Saquinavir/r was approved in the EU in August 2002. Viracept^� (nelfinavir), a leading PI is supplied by Roche outside the US and Canada. In first-line HIV therapy, Viracept delivers consistent long-term efficacy and safety. When used first line, Viracept also allows the subsequent use of both NNRTIs and other PIs for most patients due to its unique resistance pattern. FUZEON received approval from the US Food and Drug Administration (FDA) in March 2003, and from the European Commission and Switzerland in May 2003. T-1249 is being co-developed by Roche and Trimeris.

The viral load measurements in the clinical trials for FUZEON were performed using the AMPLICOR HIV-1 MONITOR^� TEST, version 1.5. This test from Roche Diagnostics is considered to be a highly sensitive measurement of the amount of HIV circulating in a patient�s blood (�viral load�). With a limited number of treatment regimens available, the accurate monitoring of viral load levels is essential to establish and monitor the effectiveness of therapeutic regimens and assess the potential onset of drug resistance.

Roche is a committed partner of the Accelerating Access Initiative to increase access to HIV care in sub-Saharan Africa and the world's Least Developed Countries. For more information on Roche policy and pricing of HIV protease inhibitors for these regions and research in HIV, visit www.roche-hiv.com.

About Roche

Headquartered in Basel, Switzerland, Roche is one of the world�s leading innovation-driven healthcare groups. Its core businesses are pharmaceuticals and diagnostics. Roche is number one in the global diagnostics market and is the leading supplier of pharmaceuticals for cancer and a leader in virology and transplantation. As a supplier of products and services for the prevention, diagnosis and treatment of disease, the Group contributes on a broad range of fronts to improving people�s health and quality of life. Roche employs roughly 62,000 people in 150 countries. The Group has alliances and research and development agreements with numerous partners, including majority ownership interests in Genentech and Chugai.

All trademarks used or mentioned in this release are legally protected.

About Trimeris

Trimeris, Inc. (Nasdaq: TRMS) is a biopharmaceutical company engaged in the discovery, development and commercialization of novel therapeutic agents for the treatment of viral disease.  The core technology platform of fusion inhibition is based on blocking viral entry into host cells.  FUZEON, recently approved in the U.S. and the European Union, is the first in a new class of anti-HIV drugs called fusion inhibitors.  Trimeris' second fusion inhibitor product candidate, T-1249, has received fast track status from the FDA and is in Phase I/II clinical testing.  Trimeris is developing FUZEON and T-1249 in collaboration with F. Hoffmann-La Roche Ltd.  For more information about Trimeris, please visit the company's website at www.trimeris.com.

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