The use of and response to second-line protease inhibitor regimens: Results from the EuroSIDA study

A. Mocroft, A. N. Phillips, V. Miller, J. Gatell, J. Van Lunzen, J. M. Parkin, R. Weber, B. Roge, A. Lazzarin, J. D. Lundgren

Research output: Contribution to journalArticlepeer-review


Objective: To describe the use of second line protease-inhibitor (PI) regimens across Europe and to determine factors associated with virological and immunological response. Design: Analysis of data from 984 patients with a median follow-up of 21 months enrolled in EuroSIDA. Patients started their second PI-containing regimen at least 16 weeks after starting the first PI-containing regimen and with viral load > 1000 copies/ ml. Methods: Virological response was defined as a viral load <500 copies/ml and immunological response as an increase of 50 × 106/I or more in CD4 lymphocyte count. Results: The median CD4 cell count at starting the second PI was 171 × 106 cells/I; viral load was 4.45 Iogcopies/ml. As a second PI regimen, 45% were using a dual PI, while of those on one PI, indinavir (42%) and nelfinavir (34%) were most common. In multivariate Cox models, a higher viral load at starting the second PI [relative hazard (RH), 0.67 per 1 log higher; 95% confidence interval (CI), 0.58-0.77; P<0.0001) and a lower CD4 cell count (RH, 1.15 per 50% higher; 95% CI, 1.06-1.26; P= 0.0014) were associated with a reduced probability of virological response. Those who had achieved viral suppression on the first Pl-regimen were more likely to respond to the second (RH, 1.65; 95% CI, 1.30-2.10; P<0.0001) as were those who added one or two new nucleosides to their second PI. Conclusions: Patients who initiate a second PI regimen at lower viral load, higher CD4 cell count or who added new nucleosides tended to be more likely to achieve a viral load <500 copies/ml. The roles of cross-resistance and adherence in response to second-line regimens needs further investigation.

Original languageEnglish
Pages (from-to)201-209
Number of pages9
JournalAIDS (London, England)
Issue number2
Publication statusPublished - Jan 26 2001


  • CD4 lymphocyte count
  • Clinic cohort
  • Protease inhibitors
  • Viral load

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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