Positive early study for Progenics’ HIV drug

PRO 140 is a humanized monoclonal antibody against CCR5 that is designed to protect healthy immune system cells from infection by HIV, the causative agent of AIDS.

Binding of PRO 140 to CCR5-expressing cells was reported in the clinical trial, with the highest PRO 140 concentration tested significantly coating CCR5 cells for at least 60 days.

The CCR5 co-receptor is a key portal of entry used by HIV to infect immune system cells; therefore, blocking this molecular doorway represents an important therapeutic target.

The results of the study indicate that PRO 140 was generally well-tolerated at all dose levels with no clinically meaningful drug-related side effects reported. In laboratory studies, PRO 140 was active against HIV strains that have acquired resistance to small-molecule CCR5 inhibitors.

“Coating of CCR5 cells with PRO 140 has been shown in prior laboratory studies to block HIV infection, and the clinical data reported today support our commitment to develop PRO 140 as a new, potentially long-acting therapy for HIV infection,” said Dr Maddon, one of the scientists who in 1996 discovered the role of CCR5 in HIV infection. “Most currently available HIV drugs slow the rate of viral replication, but they act only after HIV has infected healthy cells. Viral-entry inhibitors like PRO 140 are designed to protect cells before HIV infection occurs.”

Over the next three and a half years, Progenics will work with Weill Medical College of Cornell University, Beth Israel Medical Center and Monogram Biosciences (formerly ViroLogic) on the PRO 140 project.