New study data presented today suggest that when commercially available, doctors should not wait until all other treatment options have been exhausted before giving treatment experienced patients the investigational HIV drug Fuzeon (enfuvirtide, formerly known as T-20). The study showed that patients secured even greater benefit from combination therapy with Fuzeon when at least two other drugs within their cocktail therapy were still active against the HIV virus. The new analyses from the European and Australian Phase III Fuzeon study (TORO 2), demonstrate that Fuzeon plus two active agents in the background therapy led to a mean HIV reduction of 1.78 log₁₀ copies/mL, while the reduction with Fuzeon without any other active agents was 0.96 log₁₀ copies/mL after 24 weeks of treatment.

These results indicate greater potential benefit from the use of Fuzeon with at least two other active drugs and supplement the data from both TORO studies confirming that Fuzeon consistently adds benefit across a range of heavily treatment experienced patients with drug resistant HIV. Fuzeon combined with other antiretroviral agents consistently provides better suppressed levels of HIV and increased immune response than regimens without Fuzeon.

"Our challenge with HIV is that it is a great fighter. As we try to stop this virus, it gradually works out how to overcome every drug combination we put in its path." commented Professor Joep Lange, Academic Medical Centre, University of Amsterdam. "As a result, we have increasing numbers of patients in Europe and other developed regions in whom current drugs are no longer effective. But it comes as no surprise that while most patients see improvement with Fuzeon, those whose virus is sensitive to a greater number of HIV drugs achieve a more substantial reduction in HIV than those patients with virus sensitive to fewer drugs."

Fuzeon is the front-runner in clinical development of a new class of antiretroviral drugs called "fusion inhibitors". Unlike existing anti-HIV drugs that work inside the cell, Fuzeon is designed to block HIV from entering healthy human immune cells.

Fuzeon is active against HIV that is resistant to the currently available classes of anti-HIV drugs, addressing unmet need in increasing numbers of treatment-experienced patients. Submissions for marketing authorisations for Fuzeon were submitted with the EU EMEA and US FDA in September.

An early access programme is currently underway in Europe, US, Australia and Canada. Fuzeon is one of the most challenging molecules ever chemically manufactured at such a large scale by the pharmaceutical industry and all drug that is manufactured is being made available to patients.

"The combination of better than expected efficacy, tolerability and adherence data with the increasing incidence of drug resistance means demand for Fuzeon will be greater than initially anticipated." said Dr David Reddy, HIV Franchise Leader, Roche. "We are currently progressing the first large scale manufacturing campaign, which will be used to support the launch of Fuzeon. We will be updating our supply estimates based upon the information from the full campaign. This will then enable us to refine our plans for managing the launch to ensure continuous drug supply for all patients beginning Fuzeon therapy."

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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 in just 24 hours. The incidence of drug resistant HIV among already treated patients is increasing at a disturbing rate, with up to 78 percent of patients in North America and Europe infected with a strain of the virus that has developed resistance to one or more anti-HIV drug.

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), another 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 and T-1249 are being co-developed by Roche and Trimeris.

Headquartered in Basel, Switzerland, Roche is one of the world's leading research-oriented healthcare groups in the fields of pharmaceuticals and diagnostics. Roche's innovative products and services address prevention, diagnosis and treatment of diseases, thus enhancing people's well being and quality of life.

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

Trimeris, Inc. is a biopharmaceutical company engaged in the discovery and development 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. Trimeris has two anti-HIV drug candidates in clinical development. FUZEON, currently in Phase III clinical trials, is the most advanced compound in development. A New Drug Application (NDA) and Marketing Authorisation Application (MAA) have been submitted for FUZEON with the US FDA and the EU EMEA, respectively. 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. For more information about Trimeris, please visit the company's website at www.trimeris.com.

Note: Except for any historical information presented herein, matters presented in this release are forward-looking statements that involve risks and uncertainties. The results of Trimeris' previous clinical trials are not necessarily indicative of future clinical trials, and future results

could differ materially from past results. For a more detailed description of factors that could cause or contribute to such differences, see Trimeris' filings with the Securities and Exchange Commission.