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 HIV and Hepatitis.com Coverage of the
49
th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2009)
September 12-15, 2009, San Francisco, CA
 The material posted on HIV and Hepatitis.com about the 49th ICAAC is not approved by the American Society for Microbiology
Short-term Enfuvirtide (Fuzeon) May Promote Long-term CD4 Cell Recovery in Patients Who Start Treatment Late

Including enfuvirtide (T-20, Fuzeon) as part of a combination antiretroviral therapy (ART) regimen for patients who sought treatment very late -- when their CD4 count had already fallen below 50 cells/mm3 -- was associated with significantly faster and greater immunological recovery, according to a poster presented at the 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2009) last month in San Francisco.

By Liz Highleyman

HIV positive people who present for treatment after they have developed severe immune suppression may experience inadequate CD4 cell recovery after starting ART. Even with good virological control, continued low CD4 count can lead to increased likelihood of disease progression or death.

Researchers from the University of Torino conducted a randomized, controlled pilot study to evaluate whether adding enfuvirtide to protease inhibitor (PI)-based ART would promote immunological recovery in late presenters -- a group that accounts for about half of all new HIV diagnoses in Italy.

Enfuvirtide, which must be injected twice-daily, is generally not recommended for people starting treatment, but can improve the chances of viral load suppression in heavily treatment-experienced patients with resistant virus. Some prior studies also indicate that it improves immunological response.

The present study included 23 newly diagnosed HIV patients with a CD4 cell count below 50 cells/mm3 who did not have evidence of tuberculosis, cancer (except Kaposi sarcoma), or irreversible progressive diseases. All received lopinavir/ritonavir (Kaletra) plus 2 nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). Every other patient also received enfuvirtide, administered for at least 24 weeks or until viral load fell below 50 copies/mL.

Baseline characteristics were similar in the enfuvirtide and standard therapy arms. Most (about 85%) were men, the median age was about 40 years, and about 80% were white. The median CD4 count was very low, at about 20 cells/mm3 and the average CD4 percentage was about 3%.

Results

At 4 weeks, the decrease in viral load was greater in the enfuvirtide arm compared with the standard therapy arm (-2.9 vs -2.1 log, respectively; P = 0.01).
However, time needed to achieve viral load < 50 copies/mL was similar in the 2 groups (20 vs 17 weeks, respectively).
 
- Week 8: 169 vs 48 cells/mm3, respectively (P = 0.02);
- Week 24: 207 vs 125 cells/mm3, respectively (P = 0.01);
- Week 48: 206 vs 179 cells/ mm3, respectively (P = 0.06).
CD4 cell count remained higher in the enfuvirtide arm through 96 weeks, although the difference was no longer statistically significant at that point (348 vs 264 cells/mm3, respectively; P > 0.05).
Patients in the enfuvirtide arm took significantly less time to reach a CD4 count above 200 cells/mm3 (18 vs 48 weeks; P = 0.01).
The CD4 cell percentage was also significantly greater in the enfuvirtide arm:
 
- Week 8: 14.2% vs 6.2%, respectively;
- Week 24: 17.0% vs 8.4%, respectively (P = 0.04);
- Week 48: 19.2% vs 12.1%, respectively (P = 0.02).
CD8 cell counts did not change significantly in either group.
Consequently, the CD4/CD8 cell ratio was significantly higher in the enfuvirtide arm.
Despite the greater CD4 cell increase among enfuvirtide recipients, the incidence of immune reconstitution inflammatory syndrome (IRIS) was the same (1 in each arm).
The researchers did not report comparative rates of clinical events during follow-up.

"In this pilot study, short-course addition of enfuvirtide to a PI-based 3-drug regimen was associated [with] significantly faster and greater immunological recovery in newly discovered HIV positive patients with very low CD4 cell count," the investigators concluded. They added that an induction strategy using enfuvirtide-based ART in such patients warrants further investigation.

University of Torino, Torino, Italy.

10/02/09

Reference
S Bonora, A Calcagno, C Cometto, and others. A Long-Term Immunological Advantage Associated with a Short-Term Additional Therapy with Enfuvirtide in the Treatment of HIV Very Late Presenters. 49th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2009). San Francisco. September 12-15, 2009. Abstract H-924.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



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