An ongoing dialogue on HIV/AIDS, infectious diseases,
January 27th, 2010
No Vicriviroc — Yet
Apparently, Merck — taking over for Schering-Plough — will not seek approval for vicriviroc in treatment-experienced patients:
In two Phase III studies in this patient population, vicriviroc did not meet the primary efficacy endpoint. These studies enrolled a high percentage of patients who had three or more active drugs in their optimized background therapy regimen.
The report goes on to say that the results of these studies will be presented at CROI next month, and that other studies of vicriviroc in treatment-naive patients will continue.
Even though we don’t know the details yet, it’s understandable how this trial didn’t show any benefit for vicriviroc. With the “optimized background therapy” having 3 or more active drugs, how could it? We’re a long way from the TORO/T-20 days, when such “OBT” led to virologic suppression in < 10% of patients.
The control arms in these studies now just do too well. Progress!
Still, given the checkered history of this particular CCR5 antagonist — including a failed phase II study in treatment-naive patients and a possible signal of increased malignancies in another trial — the FDA approval for any indication might be a long hill to climb.
Paul E. Sax, MD
Associate Editor
NEJM Clinician
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