Co-receptor Tropism Assay for AIDS Patients

A new tropism assay identifies which co-receptors are used by individual strains of HIV.

The assay, called Trofile, is being used for patient selection in a clinical development program of maraviroc, a therapy for HIV/AIDS patients. Trofile was developed by Monogram Biosciences, Inc. (San Francisco, CA, USA).

Monogram has announced that its collaborator, Pfizer, Inc. (New York, NY, USA), will establish a multi-national Expanded Access Program (EAP) that will make the investigational chemokine receptor (CCR5) antagonist maraviroc available to HIV/AIDS patients who have limited treatment options due to resistance or intolerance. The two companies are collaborating to make Monogram's assay available for patient use on a global basis.

Maraviroc is designed to work differently from other available HIV medications. CCR5 antagonists block the virus from gaining access into healthy cells via the CCR5 co-receptor, a common pathway for viral entry. Monogram's Trofile co-receptor tropism assay identifies whether individual strains of HIV use the CCR5 co-receptor, the CXCR4 co-receptor, or both co- receptors to infect healthy cells. This helps clinicians determine whether a CCR5 antagonist like maraviroc may be a good therapeutic option for treating individual patients.

"This investigational therapy represents a potential milestone in the treatment of HIV,” said William Young, CEO of Monogram. "We applaud Pfizer's vision to sculpt a new model for drug development that so closely integrates advanced diagnostics into the clinical program. We are proud to be a part of this ground-breaking effort.”

Pfizer also confirmed plans to submit applications for marketing approval of maraviroc in both the United States and the European Union following review of the data from two currently ongoing phase 3 clinical trials. Pfizer's EAP is intended to provide access to maraviroc for patients who, in the opinion of the program investigators, have an urgent need for novel medicines because of viral resistance or intolerance to currently available therapies. To be eligible for the program, patients must be clinically stable with documented CCR5- tropic HIV-1 infection.

Maraviroc and other entry inhibitors currently in development come at a time when increasing drug resistance makes treating HIV more difficult than ever. Highly sensitive and precise diagnostic tools are playing an ever-more-important role in the development of new therapeutic approaches that give new hope to physicians and patients running low on options.



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Monogram Biosciences
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