Induction strategy with enfuvirtide: results from the Fuziona study, a multicenter retrospective study in Spain

Purpose of the study

To assess the therapeutic effectiveness of a strategy of induction with enfuvirtide (T20) within an optimised regimen of antiretroviral drugs (ARV) in patients infected with HIV-1 in routine clinical practice carried out in different hospitals in Spain.

Methods

We performed a retrospective multicenter study to evaluate efficacy of induction with T20. Induction strategy was defined as use of T20 in a salvage regimen for a limited period of time (without switching to another active drug). We considered "responders" as all patients who had VL <50 before stopping T20. Six months after stopping T20 we considered "rebounders" as all patients who had VL > 50 and "non-rebounders" as those who maintained VL <50. We explored risk factors for virological rebound after stopping T20.

Summary of results

62 patients included (16 women) from 10 hospitals, mean age 43 years, median time since HIV diagnosis: 16 years. 43% CDC C3. Before starting salvage regimen, median CD4 count was 154 cells and median VL was 4.2 log. Patients had had six previous ARV regimens on average. Genotyping showed M184V in 57.4%, K103N in 34.4%, TAMs in 72.1%, and 41% had at least five PI mutations. Patients received T20 for a median of 9.3 months (1.2–34.3).

Forty-one patients (66.1%) were responders. Of these 41 patients, 37 (90.2%) were non-rebounders. The salvage regimen in non-rebounders contained: TDF and FTC (59%), LPV/r (35%) DRV/r (21.6%), TPV/r (18.9%), SQV/r (10.8%) and ATV/r (one pt), FOS-APV/r (one pt), RAL (8.1%) and MVC (one pt). Rebounders were treated with TDF and FTC (75%), TPV/r (two pts), LPV/r (one pt) and FAM/r (one pt). No significant differences were found.

Conclusion

In contrast with prior studies, the majority of patients who achieved viral suppression after starting T20 maintained suppression after stopping it. This is probably related to the higher antiviral activity of the background regimen. (Table 1.)

Table 1