Switch EFV to ETR: CNS toxicity

Waters L. AIDS. 2011 Jan 2;25(1):65-71

Type of ARV Trial
Switch studies in virologically suppressed patients
» Switch NNRTI to NNRTI
» EFV vs ETR


  • Switching EFV to ETR led to a significant reduction in overall grade 2-4 CNS adverse events, including insomnia, abnormal dreams and nervousness as individual adverse event
  • No virological failures occurred in the 19 and 15 patients completing 24 and 12 weeks of once-daily ETR-based HAART
  • Improvement in lipids with significant reductions in total and
    LDL-cholesterol after 12 weeks of ETR
  • Proactive switch away from EFV may yield significant reductions in CNS toxicity



  • Primary Endpoint: change in proportion of patients experiencing grade 2-4 CNS
    toxicity at W12
  • Secondary endpoints: change in CNS score at W12 and W24; combined change (immediate and delayed switch) 12 weeks after switch; median number of grade 2-4 CNS adverse events; viral suppression ; CD4 change; fasting lipids; safety

Baseline characteristics and disposition

* Frequency of individual events similar in both groups except for insomnia (75% vs 39%, p = 0.024)

  • Median duration of EFV exposure: 21.4 months

Primary endpoint

  • Grade 2-4 CNS AE at W12: 60% in immediate switch vs 81.3% in deferred switch (significant decrease in immediate switch; p = 0.041)
  • Abnormal dreams
    • decrease from 50% to 20% in IS group (p = 0.041) vs no change in DS : 67% to 63%
  • Median number of grade 2-4 CNS AE
    • IS: 4 at baseline vs 1.5 at W12 (p = 0.003)
    • DS: 3 at baseline vs 3 at W12
  • CNS score: IS = change from 14 to 6 (p = 0.001); DS = 10 to 7.5 (NS)

Change from W12 to W24

  • No further significant change in immediate switch group
  • Significant improvement in deferrred group

Other results

  • No virologic failure
  • Improvement in lipids after switch to ETR
  • Grade 2 AE deemed related to ETR: fatigue, headache, reduced libido