Durability and Outcomes of First-line Antiretroviral Regimens

By Liz Highleyman

Little is known about time trends, predictors, and consequences of changes to antiretroviral therapy soon after starting an initial HAART regimen, according to investigators with the Swiss HIV Cohort Study writing in the June 15, 2008 Journal of Infectious Diseases.

To shed light on this issue, the researchers compared the incidence of, reasons for, and predictors of treatment changes within 1 year after starting combination HAART, as well as virological and immunological outcomes at 1 year.

The study included 1866 participants from the Swiss HIV Cohort who started combination HAART during 3 periods: 2000-2001, 2002-2003, or 2004-2005.

CONTINUING EVOLUTION OF HAART

Results:

• The durability of initial antiretroviral regimens did not improve over time:

• 48.8% of 625 patients switched within 1 year during 2000-2001;
• 43.8% of 607 did so during 2002-2003;
• 44.3% of 634 did so during 2004-2005.

• Reasons for changing therapy included:

• Intolerance and drug toxicities (51.1% of all participants);
• Patient choice (15.4%);
• Physician decision (14.8%);
• Virological failure (7.1%).

• Increased probability of treatment change was associated with:

• Higher CD4 cell count;
• Higher HIV RNA viral load;
• Use of regimens containing stavudine (d4T; Zerit) or ritonavir-boosted indinavir (Crixivan).

• Decreased probability of changing therapy was associated use of tenofovir (Viread).

• Treatment discontinuation was associated with:

• Higher CD4 cell count;
• Current use of injection drugs;
• Use of regimens containing nevirapine (Viramune).

• 1-year outcomes improved between 2000-2001 and 2004-2005:

• 84.5% and 92.7% of patients, respectively, achieved an undetectable viral load below 50 copies/mL.
• Median CD4 cell increases in the 2 period were 158 and 198 cells/mm3, respectively.

Based on these findings, the study authors concluded, "Virological and immunological outcomes of initial treatments improved between 2000-2001 and 2004-2005, irrespective of uniformly high rates of early changes in treatment across the 3 study intervals."

A similar study looking at patients at the Royal Free Hospital in London Cohort found that fewer individuals changed therapy during the 2000-2006 period - especially due to drug toxicities -- but also observed a higher rate of change with stavudine and a lower rate with tenofovir.

6/13/08

Reference
TT Vo, B Ledergerber, O Keiser. Durability and outcome of initial antiretroviral treatments received during 2000-2005 by patients in the Swiss HIV Cohort Study. Journal of Infectious Diseases 197(12): 1685-1694. June 15, 2008.