A phase IV, double-blind, multicentre, randomized, placebo-controlled, pilot study to assess the feasibility of switching individuals receiving efavirenz with continuing central nervous system adverse events to etravirine.

BACKGROUND

Two nucleoside reverse transcriptase inhibitors (NRTIs) and efavirenz (EFV) is a recommended initial regimen for HIV-1. Most EFV-related central nervous system (CNS) toxicity resolves early though symptoms may persist; we studied switching to etravirine (ETR) in these individuals.

METHODS

A randomized, double-blind trial in patients with viral suppression but ongoing CNS adverse events after more than 12 weeks EFV. Patients received 2NRTI/EFV/ETR-placebo (delayed switch) or 2NRTI/ETR/EFV-placebo (immediate switch) for 12 weeks followed by 12-week open-label phase (2NRTI/ETR). Primary end-point was percentage with G2-4 CNS adverse events at 12 weeks.

RESULTS

Thirty-eight men; 20/18 were randomized to immediate switch/delayed switch; median CD4 was 444/498 cells/μl, respectively. Baseline CNS adverse events were similar. Nineteen immediate switch patients completed follow-up (one lost to follow-up) and 13 on delayed switch (two lost to follow-up, two withdrawn consent, one adverse event). Immediate switch G2-4 CNS adverse event: 90% at baseline, 60% at week 12 (P = 0.041). Delayed switch G2-4 CNS adverse event: 88.9% at baseline, 81.3% at week 12 (P = ns). Combined (both arms) percentage decline in G2-4 CNS adverse event after 12 weeks of ETR was significant for overall adverse events, insomnia, abnormal dreams and nervousness (P = 0.009, 0.016, 0.001, and 0.046, respectively). All participants on study maintained HIV-RNA below 50 and median week 24 CD4 was 593 and 607 cells/μl on immediate switch and delayed switch. Two participants experienced new G3-4 adverse events [delayed switch: G3 flatulence on EFV); immediate switch: G4 viral URTI on ETR (SAE)].

CONCLUSION

Switching EFV to ETR led to a significant reduction in overall G2-4 CNS adverse events, including insomnia, abnormal dreams and nervousness as individual adverse event. Lack of improvement for some events suggests other causative factors.