Merck’s HIV treatment fails in phase III
pharmafile | February 18, 2010 | News story | Research and Development | HIV, Merck
Merck’s HIV treatment vicriviroc has disappointed in phase III trials, and may be dropped by the company.
The results failed to show the drug was any more effective than existing gold standard regimens (‘optimised background therapy’ or OBT) for treating HIV patients.
Most patients on the trial were adding the drug to an existing regimen of three or four HIV treatments, and vicriviroc’s failure reflects industry-wide difficulties in finding new drugs to improve on current therapies.
Presenting the data at the Conference on Retroviruses and Opportunistic Infections in San Francisco, Merck said it was now considering its options for the drug, which could see a different patient group targeted, or the drug abandoned altogether.
“While these results are disappointing, it is becoming increasingly difficult for an additional HIV medicine to demonstrate a significant incremental benefit as the fourth or fifth drug added to optimised background therapy,” said Lisa Dunkle, executive director clinical research, Merck Research Laboratories.
“We will further evaluate these results to better understand these findings and define a potential path forward for vicriviroc.
Merck confirmed that it would not submit a New Drug Application (NDA) for vicriviroc in this patient population at this time.
Of the 857 patients enrolled in the VICTOR-E3 and VICTOR-E4 studies, nearly a quarter (215) discontinued treatment with Vicriviroc due to treatment failure or adverse side-affects.
Vicriviroc is an investigational HIV CCR5 receptor antagonist, used in treatment-experienced patients HIV-infected patients. It is an extracelluar inhibitor of the HIV infection, and it is designed to prevent the virus from infecting the immune system’s CD4 cells by acting as an antagonist to its primary entry route, the CCR5 receptor.
The company said an ongoing phase II clinical study of vicriviroc in treatment-naïve HIV-infected patients will continue unchanged. Treatment-experienced patients from the vicriviroc clinical trials who continue to benefit from vicriviroc treatment will still have access to the medicine as provided for in the trial protocols.
Encourgaging Isentress data
The company enjoyed more encouraging news from its other HIV treatment, Isentress. New data on the drug suggest it has longer term efficacy and a better tolerability profile than BMS’ Sustiva (efavirenz).
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