Investor Update

Basel, 12 July 2004

New data finds Fuzeon-based therapy provides significant long-term benefit

Fuzeon (enfuvirtide), the first and only fusion inhibitor for the treatment of HIV, durably suppresses HIV and provides continuous increases in immune (CD4) cells over a period of 96 weeks, according to new data presented today at the XV International AIDS Conference (IAC). In another key study finding, more than half of treatment-experienced patients (56 percent) who began using Fuzeon at the outset of the study were successful in completing 96 weeks of treatment. Additionally, investigators reported no late-emerging safety issues associated with the long-term use of Fuzeon.

“The new data show that the significant virological and immunological benefits of Fuzeon seen in earlier analyses are extended to 96 weeks, an especially notable achievement given the extensive prior drug exposure of patients enrolled in the TORO studies,” said Corklin Steinhart M.D., Senior Attending Physician, Mercy Hospital, Miami, FL. “It is particularly exciting that more than half of patients who began treatment with Fuzeon continued on the drug for 96 weeks. This news, coupled with the positive 96-week safety analysis, should be encouraging to patients who are considering Fuzeon as a long-term treatment option.”

The high prevalence of HIV drug resistance among patients in the U.S. highlights the need for newer HIV drugs, like Fuzeon, that are active against drug-resistant virus. Data recently presented at the XII International Drug Resistance Workshop, from a large cohort of HIV-infected individuals prescribed antiretroviral therapy from 2001-2003, showed that four out of five of those tested had resistance to at least one anti-HIV drug.¹ Thirty-nine percent were found to have resistance to a drug in two classes, and 18 percent had resistance to a drug in three classes. These data are consistent with previous findings from a different study recently published in AIDS by Dr. Douglas Richman, which showed that 76 percent of US patients with measurable viral load in 1996-1998 carried a strain of the virus that is resistant to at least one drug.²

Delayed initiation of Fuzeon may compromise response
The data presented at IAC were from a 96-week analysis of the TORO studies, two randomized, open-label trials that together enrolled approximately 1,000 HIV infected patients who had previously been treated with an average of 12 antiretrovirals. Patients were randomized to receive a regimen of anti-HIV drugs with or without Fuzeon. Patients randomized not to receive Fuzeon were allowed to add Fuzeon to their regimens after week eight if they met virological failure criteria or at the 48 week timepoint.

Patients who were randomized to receive a Fuzeon-based regimen had significantly lower levels of the virus and higher CD4 counts at 96 weeks compared those randomized to a regimen without Fuzeon. Patients originally in the non-Fuzeon control arm who were later switched to Fuzeon (after virological failure) showed a mean reduction in viral load at week 96 of 1.1 log₁₀ copies/mL, compared to a 2.1 log₁₀ copies/mL mean reduction for patients randomized to the Fuzeon arm – thereby highlighting the potential consequences of delaying the initiation of treatment with Fuzeon.

Patients in the Fuzeon arm saw continuous improvements in CD4 cells over the study period, with the mean CD4 increase from baseline of 166 cells/mm³ at week 96. In contrast, patients who used Fuzeon after switching from a non-Fuzeon regimen, experienced a mean increase of 116 cells/mm³ from baseline at week 96.

96-week safety
No new safety issues were identified in the 96-week analysis, and there was no evidence of long-term or cumulative toxicities. Rather, patients in the Fuzeon arm experienced less diarrhea, nausea and fatigue, side effects often associated with antiretroviral therapy. Injection site reactions, which were found to not increase in severity over 96 weeks, are the most common adverse event associated with use of Fuzeon.

Adherence to Fuzeon-based regimens at 48 weeks
In a separate poster presentation at IAC, adherence to Fuzeon-based regimens was found to be high, and similar to adherence rates among patients taking a regimen of oral drugs only. Furthermore, adherence to Fuzeon-based regimens was not influenced by baseline disease status, treatment history or prior intravenous drug use.

About Fuzeon
Fuzeon was granted accelerated approval on the basis of 24-week data by the U.S. Food and Drug Administration in March 2003, and is also approved in the European Union, Switzerland and Canada. Fuzeon leads the first class of anti-HIV drugs with a unique mechanism of action to be introduced in seven years. Unlike other HIV drugs that work after HIV has entered the human immune cell, Fuzeon works outside the CD4 cell, blocking HIV from entering the cell. For this reason, Fuzeon is effective in treatment-experienced patients who have developed resistance to other anti-HIV drugs, though patients may still develop resistance to Fuzeon.

Fuzeon (enfuvirtide) in combination with other antiretroviral agents is indicated for the treatment of HIV-1 infection in treatment-experienced patients with evidence of HIV-1 replication despite ongoing antiretroviral therapy. This indication is based on analyses of plasma HIV-1 RNA levels and CD4 cell counts in controlled studies of Fuzeon of 24 weeks’ duration. Subjects enrolled were treatment-experienced adults; many had advanced disease. There are no studies of Fuzeon in antiretroviral-naive patients. There are no results from controlled trials evaluating the effect of Fuzeon on clinical progression of HIV-1.

Roche in HIV
Roche is at the forefront of efforts to combat HIV infection and AIDS, committed for 15 years to groundbreaking research and development of new drugs and diagnostic technology. The objective is to provide tailored treatment solutions and an improved standard of care worldwide for those people living with HIV.

Roche and Trimeris are working together to discover, develop and commercialize the next generation of HIV fusion inhibitors.

About Trimeris, Inc.
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(R), approved in the U.S., Canada and European Union, is the first in a new class of anti-HIV drugs called fusion inhibitors. Trimeris is developing Fuzeon and future generations of peptide fusion inhibitors in collaboration with F. Hoffmann-La Roche Ltd. For more information about Trimeris, please visit the Company's website at http://www.trimeris.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, 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 65,000 people in 150 countries. The Group has alliances and R&D agreements with numerous partners, including majority ownership interests in Genentech and Chugai.

¹ Smith, A.J., et. al. “Prevalence of Mutations Associated with Antiretroviral Drug Resistance in a Cohort of Treated Individuals in Four Cities.” Antiviral Therapy 2004; 9S112.
² Richman,D. et. al. “The Prevalence of Antiretroviral Drug Resistance in the United States.” AIDS Vol. 18, July 2004: 1393-1401.


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