Decides to Stop Development of Vicriviroc for Treatment of HIV
Research Laboratories announced on July 15 that it would
discontinue development of its investigational CCR5
antagonist vicriviroc for the treatment of HIV infection
in both treatment-naive and treatment-experienced patients,
due to unimpressive results in clinical trials. All
ongoing studies of the drug, as well as long-term open-label
distribution, will be halted.
presented data at the 17th Conference on Retroviruses and Opportunistic
Infections this past February showing that vicriviroc did not demonstrate
non-inferiority to an optimized background regimen plus placebo
among treatment-experienced participants in the twin VICTOR trials.
The drug did perform well for people with fewer active background
drugs, however, raising the issue of how the benefits of new drugs
should be evaluated in an era of highly effective antiretroviral
previously reported, Merck informed investors in January that
it did not plan to seek U.S. Food and Drug Administration (FDA)
approval of vicriviroc for treatment-experienced patients, but
at the time indicated that the company would continue to evaluate
the drug as first-line therapy. Merck has now decided to stop
testing vicriviroc in this group too, based on data from a Phase
2 trial that will be presented at an upcoming scientific meeting.
a statement issued July 15, 2010, the company stated:
has decided to discontinue the development of vicriviroc for the
treatment of HIV infection. This decision was based on the overall
clinical data from Phase III trials in treatment-experienced patients
and a recently completed Phase II trial in treatment-naive patients.
ongoing clinical studies of vicriviroc, including those that involve
long-term open-label distribution of the therapy, will be terminated,
and study participants will be transitioned to appropriate available
has a long-standing commitment to the research and development
of innovative therapies for people with HIV that spans nearly
25 years and remains committed to HIV research and to the development
of new therapies."
addition, Lisa Dunkle, Merk's Executive Director of Clinical Research,
sent a letter to investigators urging them to wind up ongoing
clinical trials as soon as possible.
should plan as soon as feasible to bring in all study subjects
still receiving vicriviroc for evaluation and for you to determine
the best regimen of available antiretroviral agents for them to
receive in your location," she wrote. "Where time is
required to obtain these agents, Merck will try to work with you
to assure a smooth transition, recognizing that we have a limited
supply of vicriviroc at this time."
said it will halt development of vicriviroc for the treatment
of HIV infection, but did not say whether the company plans to
pursue research for other indications.
Statement from Merck regarding the development of vicriviroc for
the treatment of HIV infection. July 15, 2010.
Dunkle. Investigator Letter. July 15, 2010.