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and Hepatitis.com Coverage of the
17th Conference on Retroviruses and
Opportunistic Infections (CROI 2010)
February 16 - 19, San Franciso, California
Treatment Intensification with Maraviroc (Selzentry) Did Not Raise CD4 Cell Counts in Small Study
Some clinical trials of maraviroc indicated that the drug produced larger and faster CD4 cell gains than placebo or competing regimens, although the primary end-points of these studies involved virological suppression not immune restoration.
To learn more about this issue, Timothy Wilkin from Weill Cornell Medical College and colleagues performed a small study looking at the effect of ART intensification with maraviroc on CD4 counts in patients with suboptimal CD4 cell recovery.
ACTG 5256 was a single-arm pilot trial that included 34 participants with a CD4 count < 250 cells/mm3, a calculated CD4 slope (rate of decline) between -20 and +20 cells/mm3 per year, and undetectable plasma viral load for 48 weeks prior to study entry.
All but 2 of the participants were men, about 70% were white, and the median age was 50 years; notably, this is older than the typical average age of participants in HIV clinical trials, reflecting the tendency toward poorer immune recovery among older patients. The median duration of viral load suppression on ART was 3 years prior to starting the study.
Participants added maraviroc to their existing virologically suppressive ART regimen for 24 weeks. The primary end-point was the change in averaged CD4 counts from baseline to week 22-24.
also performed extensive immuno-phenotyping -- or characterization of
immune cells and the chemical messengers they produce -- at baseline
and at the end of maraviroc treatment.
Based on these findings the researchers concluded, "Adding maraviroc to a suppressive antiretroviral regimen was not associated with the hypothesized increase in CD4 counts."
However they noted, "Maraviroc intensification was associated with decreased immune activation" as shown by reduced CD38 percentage and HLA-DR/CD38, and improvement in markers of apoptosis."
clinical significance of these findings is unknown," they continued.
"Further studies of CCR5 antagonists to dampen immune activation
associated with HIV infection are warranted."
Weill Cornell Medical College, New York, NY; Harvard School of Public Health, Boston, MA; Rush University Medical Center, Chicago, IL; University of Pittsburgh School of Medicine, Pittsburgh, PA; Massachusetts General Hospital, Boston, MA; Univsity of California, Los Angeles, CA.