European Committee Issues Positive Opinion of Pfizer's Celsentri(R) (Maraviroc) for Treatment-Experienced Patients Infected with CCR5-tropic HIV-1

SOUTH SAN FRANCISCO, Calif., July 20 /PRNewswire-FirstCall/ -- Monogram Biosciences, Inc. announced today that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA) issued a positive opinion recommending marketing authorization of collaborator Pfizer, Inc.'s investigational HIV medication Celsentri (maraviroc) - the first CCR5 antagonist for use along with other antiretroviral agents for treatment-experienced adult patients infected with CCR5-tropic HIV-1.

A final decision from the European Commission, which has the authority to approve medications for the European Union, is expected within months.

Pfizer also noted that 48-week data from the two MOTIVATE clinical trials confirmed 24-week findings reported in February 2007 and led to the positive opinion from the CHMP.

If approved, Celsentri would be the first member of a new class of oral HIV medicines in more than a decade. Monogram's Trofile(TM) Assay has been used to select patients for the drug's clinical trials.

"Information provided by Pfizer to the April 24, 2007 U.S. FDA advisory committee indicates that "the results in treatment-experienced patients with CCR5-tropic versus non-CCR5- tropic HIV-1 provide clinical data validating Monogram's Trofile Assay as an effective and appropriate means to identify patients with CCR5-tropic HIV-1 and who are therefore likely to respond to maraviroc,"" said William Young, Monogram CEO.

"We expect to make our Trofile Assay available commercially in European markets after Celsentri is approved," continued Young. "Outside the U.S., we are partnering with Pfizer where Pfizer is taking the lead in marketing Trofile and we are implementing the necessary logistical arrangements to make sure the assay can be made available in concert with Celsentri. We expect to be ready for commercial availability in as many as eight countries this year, with an additional forty countries in the planning stages."

About Monogram Biosciences, Inc.

Monogram is advancing individualized medicine by discovering, developing and marketing innovative products to guide and improve treatment of serious infectious diseases and cancer. The Company's products are designed to help doctors optimize treatment regimens for their patients that lead to better outcomes and reduced costs. The Company's technology is also being used by numerous biopharmaceutical companies to develop new and improved antiviral therapeutics and vaccines as well as targeted cancer therapeutics. More information about the Company and its technology can be found on its web site at http://www.monogrambio.com/.

Forward-Looking Statements

Certain statements in this press release are forward-looking. These forward-looking statements include references to the potential use of our Trofile Assay as a molecular diagnostic for patient selection for Pfizer's CCR5 antagonist maraviroc, if approved by the FDA and European authorities. These forward-looking statements are subject to risks and uncertainties and other factors, which may cause actual results to differ materially from the anticipated results or other expectations expressed in such forward-looking statements. These risks and uncertainties include, but are not limited to: the risk that regulatory authorities may not require a molecular diagnostic for patient selection for maraviroc, the risk that maraviroc will not be approved by the FDA or European authorities; risks related to the implementation of the collaboration with Pfizer; risks associated with establishing and maintaining logistics arrangements in European and other non-U.S. markets for Trofile; risks and uncertainties relating to the performance of our products; the growth in revenues and actual market acceptance of our products; the impact of competition; whether payors will authorize reimbursement for our Trofile; whether the FDA or any other agency will decide to further regulate Trofile and our other products; the ultimate validity and enforceability of our patent applications and patents; the possible infringement of the intellectual property of others; whether licenses to third party technology will be available; and whether we will be able to raise sufficient capital in the future, if required. For a discussion of other factors that may cause our actual events to differ from those projected, please refer to our most recent annual report on Form 10-K and quarterly reports on Form 10-Q, as well as other subsequent filings with the Securities and Exchange Commission. We do not undertake, and specifically disclaim any obligation, to revise any forward-looking statements to reflect the occurrence of anticipated or unanticipated events or circumstances after the date of such statements.

Trofile is a trademark of Monogram Biosciences, Inc. Celsentri is a registered trademark of Pfizer, Inc.

Press Release contacts: Alfred G. Merriweather Chief Financial Officer Tel: 650 624-4576 amerriweather@monogrambio.com Jeremiah Hall Feinstein Kean Healthcare Tel: 415 677-2700 jeremiah.hall@fkhealth.com