Switching from enfuvirtide to etravirine – efficacy results from the etravirine expanded access programme

Background

The next generation NNRTI etravirine (ETR, TMC125) and the fusion inhibitor enfuvirtide (T-20) have shown strong efficacy in the DUET and TORO trials, respectively. Switching from enfuvirtide to etravirine could improve convenience and tolerability, and reduce treatment costs. In the TMC125-C214 trial (global etravirine expanded access programme), treatment-experienced patients with undetectable HIV-RNA levels were permitted to switch from enfuvirtide to etravirine.

Methods

Patients who switched from enfuvirtide to etravirine, with screening HIV-RNA less than 50 copies/mL, were followed up for 24 weeks. Data were monitored and analysed for patients in Europe and Canada. Patients could optimise other parts of the background regimen at the time of switch from enfuvirtide to etravirine.

Summary of results

Overall, there were 34 patients switching from enfuvirtide to etravirine in Europe (n = 24) and Canada (n = 10). Of these, 24% were female, 97% were Caucasian, with a mean age of 48 years. The baseline median CD4 count was 351 cells/uL (range 90–935). Within this study, 33 of the 34 patients (97%) used DRV/r in the background regimen, with raltegravir used in 50%, maraviroc in 9%, and NRTIs for 91%. The percentage of patients with HIV-RNA suppressed below 50 copies/mL was 83% at week 4, 86% at week 12 and 93% at week 24. Of those with HIV-RNA not <50 copies/mL at week 12, there were five HIV-RNA levels just above the detection limit (50, 52, 52, 58 and 217 copies/mL) and one patient with HIV-RNA = 5,070. This patient also had HIV-RNA above 50 copies/mL at week 24 (4,730 copies/mL). Mean CD4 counts remained above baseline through week 24. There were four serious adverse events reported: these were all judged to be unrelated to etravirine treatment by the investigators and the dose of etravirine was not changed.

Conclusion

The vast majority of patients who switched from enfuvirtide to etravirine have sustained HIV-RNA suppression below 50 copies/mL for up to 24 weeks of study, with stable or rising CD4 counts.