Session 67Poster Presentations Therapy Experienced Patients Session Day and Time: Wednesday 1:30 - 3:30 pm Room: Hall A
567 Response to a Second Treatment Regimen Following Virologic Failure M. Fischl*1, H. Ribaudo2, A. Collier3, J. Feinberg4, N. Rajicic2, A. Erice5 1Univ of Miami, FL; 2Harvard Sch of Public Hlth, Boston, MA; 3Univ of Washington, Seattle; 4Univ of Cincinnati, OH; and 5Hosp Asepeyo, Madrid, Spain
Background: Success of second-treatment regimens following virologic failure (VF) with a first potent treatment regimen in patients (pts) with advanced HIV infection is not well known. We examined the outcomes of second antiretroviral regimens among subjects with VF treated with zidovudine and lamivudine, plus either indinavir (IDV), efavirenz + indinavir (EFV+IDV), or nelfinavir + indinavir (NFV+IDV) as part of ACTG 388, a randomized phase III study.
Methods: Subjects with confirmed VF (HIV RNA3 baseline or 1.0 log above nadir (early VF), > 200 copies/ml at wk 24 or relapse) had the option of continuing the same first regimen, switching to a protocol-defined second regimen, or seeking treatment outside the study (non-protocol defined second regimen). Resistance testing was done at VF to optimize therapy. Subjects were evaluated at the time of VF and q 8 wks thereafter with HIV-1 RNA levels and CD4 cell counts. Descriptive analyses were used.
Results: At the time of VF, 134 subjects were on study treatment and 38 had discontinued study treatment. Of the 134, 76 remained on the same first regimen after VF (34/76 subsequently began a second regimen), 12 switched to protocol-defined second regimens, 2 switched to non-protocol second regimens, 41 temporarily interrupted their first regimen (26 began a second regimen), and 3 permanently discontinued study treatment. Of the 76 subjects who continued their first regimen, 35 (47%) responded (HIV-1 RNA < 200 copies/ml); 12/24 on IDV, 11/20 on EFV+IDV, and 12/32 on NFV+IDV. Subsequent response did not depend on the type of VF. Of the 71/74 subjects with RNA values who started a second regimen, 39 responded (54%); 12/22 on prior IDV, 6/15 on prior EFV+IDV, and 21/34 on prior NFV+IDV. A greater proportion (22/30) with virologic relapse responded compared with other types of VF (17/41). Of the 48 subjects with genotypic results, responses were seen in 25 (6/11 wild-type virus; 15/27 M184V mutation; 1/4 M184V/NNRTI mutations; 2/4 NNRTI mutations; 2/2 TAMs).
Conclusions: Overall, subjects with advanced HIV disease who had VF on first regimen responded to a second regimen. Those with virologic relapse had better outcomes.
