Abstract 510/Session65
Virologic responses to a Ritonavir/Saquinavir containing regimen in Patients who have previously failed Nelfinavir.
P TEBAS*, E KANE, M KLEBERT, J SIMPSON, WG POWDERLY, K HENRY. Wash Univ, St. Louis, MO.Univ of Minnesota, Minneapolis MN, Regions Hospital,St. Paul, MN
Objectives The effectiveness of a second protease inhibitor (Pl) in patients who failed aninitial Pl is unclear but believed to be low. It has been postulated however that patients who fail nelfinavir may respond differently. We therefore assessed the virologic response to aritonavir/saquinavir containing regimen in patients that have previously failed nelfinavir.
Methods 27 patients enrolled in the phase 11 nelfinavir clinical trials (AG506, AG511 andAG525) at our 2 sites who failed (two consecutive HIV viral loads > 5000 copies per ml(bDNA assay)) were switched to a combination of D4T 40 mg bid, 3TC 150 mg bid, ritonavir.400 mg bid and sequinavir 400 mg bid.
Results Patients had taken nelfinavir for a median of 52 weeks. 33% of them had a complete virologic response to the
nelfinavir containing regimen. 20 of those patients were naive or had limited prior antiretroviral therapy prior to treatment with
nelfinavir-containing regimens (AG506 and AG511). 1 patient discontinued study at 3 weeks. 19/19 (100%) of the remaining patients reached
undetectable viral loads (<500 copies) that were sustained at week 16 in 9/10 (90%) subjects. Only 3/7 (43%) of the patients with
extensive prior antiretroviral therapy (AG525) reached undetectability. The regimen was well tolerated. The most frequent baseline
mutations in the protease gene prior to switching were D30N(17/25) and L90M (5/25).The presence or absence of these mutations was not
predictive of a short-term virologic response.
Conclusions Most patients who failed a nelfinavir-containing regimen responded to a switch to a combination regimen with saquinavir/ritonavir. The durability of this response through 24-weeks of follow up and its relationship to baseline protease gene mutations will bepresented. |
