Switching from a toxicity-causing antiretroviral to enfuvirtide in patients with HIV: the SWITCH TOX study.

PURPOSE

Treatment-related toxicities frequently limit antiretroviral therapy for patients with HIV-1 infection. This study evaluated the changes in treatment-limiting toxicities when the primary toxicity-causing agent was replaced with enfuvirtide.

METHOD

Adult patients with HIV-1 infection (N = 91) with antiretroviral treatment-limiting toxicities were enrolled in this multicenter, open-label, single-arm, 24-week study. Enfuvirtide 90 mg bid was administered instead of a single toxicity-causing component of the previous antiretroviral regimen. Changes in severity of antiretroviral toxicity, safety, tolerability, and maintenance of efficacy of the enfuvirtide regimen were evaluated at baseline and at 4, 8, 12, and 24 weeks.

RESULTS

Eighty-four percent of participants completed the study. Injection site reactions with enfuvirtide caused premature withdrawal in 5 participants (5%); a further 10 participants (11%) also withdrew early. Overall antiretroviral-related, treatment-limiting toxicities improved or resolved in 53% of participants switching to enfuvirtide, remained unchanged in 43%, and worsened in 3%. At Week 24, 66% of participants (60/91; intent-to-treat population) maintained or improved their viral load category and 73% of participants (66/91) maintained or improved their CD4 cell counts.

CONCLUSION

Replacing a toxicity-causing antiretroviral with enfuvirtide may reduce toxicity without compromising the efficacy of different antiretroviral regimens.