Monogram Biosciences Launches First Resistance Assay For HIV Integrase Inhibitors

PhenoSense Integrase Now Enables Clinicians to Monitor Activity of New Class of Potent Antiretroviral Drugs

South San Francisco, CA - Monogram Biosciences, Inc. announced the launch of its PhenoSense Integrase assay, built on Monogram's proprietary technology platform, PhenoSense. The assay directly measures the susceptibility of HIV to a new and potent class of integrase inhibitor drugs that blocks viral replication by preventing viral genes from integrating into the DNA of newly infected cells. Together with PhenoSense GT, PhenoSense Integrase provides the most complete picture of resistance to antiretroviral therapies.

PhenoSense Integrase along with other Monogram assays were used to support the clinical trials of the first commercially-available integrase inhibitor, Merck's Isentress (raltegravir), which received U.S. Food and Drug Administration (FDA) approval in October 2007. In Merck's phase III BENCHMRK trials, Monogram's PhenoSenseGT was used to select optimized drug regimens in the placebo and Isentress-containing treatment arms while PhenoSense Integrase was used to identify and characterize Isentress resistant viruses in treatment failures. The company is also actively involved in the clinical evaluation of Gilead's integrase inhibitor candidate, elvitegravir, currently in Phase III studies. In addition to drug resistance, PhenoSense Integrase also measures reductions in viral replication capacity associated with integrase inhibitor resistance that may help characterize viral fitness.

"Using new antiretroviral drugs correctly today, including HIV integrase inhibitors, is critically important since the pipeline for additional new agents is not likely to provide treatment options beyond our current choices for a number of years," said Dr. Charles Hicks, Associate Professor of Medicine at Duke University Medical Center. "Tools like HIV resistance phenotype tests (including Monogram's PhenoSense Integrase and PhenoSense GT assays) and the HIV tropism assay (Trofile) are important tools to help clinicians make good choices. They can also help with modifying regimens that are not suppressive by determining whether additional resistance has emerged and which drugs are no longer active."

"As the first and only commercially available assay to measure integrase inhibitor resistance, PhenoSense Integrase exemplifies Monogram's leadership position in personalized medicine and the Company's continued commitment to develop innovative HIV diagnostics that tailor drug treatments to the individual patient," said Monogram CEO William Young. "As evidenced by today's product launch and last year's introduction of Trofile, Monogram is firmly committed to ensuring that cutting-edge diagnostics are readily available to meet the needs of patients and physicians."

The performance of the PhenoSense Integrase assay is validated in compliance with regulations specified by the Clinical Laboratories Improvement Amendments (CLIA) and is performed in Monogram's Clinical Reference Laboratory, which is accredited by the College of American Pathologists (CAP).

About PhenoSense Integrase Assay
PhenoSense Integrase determines the susceptibility of a patient's HIV-1 strain to integrase inhibitors. The region of the HIV genome that encodes integrase is amplified from a patient blood sample and inserted into a proprietary test vector that is used to generate virus particles that replicate using the patient virus integrase protein. Completion of a single replication cycle results in the production of luciferase activity in infected cells. Infection in the presence of drug is performed to determine whether a patient virus is sensitive or resistant to integrase inhibitors. Based on the amount of luciferase activity produced in the absence of drug, PhenoSense Integrase also provides a measure of replication capacity (RC) of integrase inhibitor sensitive and resistant viruses.

About Monogram
Monogram is a biotechnology company 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.

SOURCE: Monogram Biosciences