The Body Covers: The 7th Conference on Retroviruses and Opportunistic Infections
Antiretroviral Chemotherapy: Treatment-Experienced Patients
February 1, 2000
Poster 525: Continued Lamivudine (3TC) vs. Delavirdine (DLV) in Combination with Indinavir (IDV) and Zidovudine (ZDV) or Stavudine (d4T) in 3TC-Experienced Patients: 48-Week Follow-Up of ACTG 3703TC has been shown to provide continued suppression of viral load and increased T-cells even in the face of resistance (possibly because the 184 mutation that causes resistance to 3TC may be less "fit" than wild type virus). This small complicated trial addressed whether continuing 3TC has benefit over switching to a new agent.
The most important component of this trial looked at patients treated in ACTG 370 with either ddI/3TC or d4T/3TC. Patients were switched to indinavir/AZT and either continued 3TC or also added in delavirdine. Not surprisingly, there was a significantly higher percentage of patients in the delavirdine arm with viral loads <50 at 48 weeks, although there was not a significant difference in T-cell increase.
This trial reconfirms that it is best to change all possible drugs in a new regimen, but unfortunately does not answer the question of whether retaining 3TC is of benefit. It has been shown multiple times that adding a new class of drugs leads to improved results, which delavirdine, but not 3TC does. In addition, as a cytochrome p450 inhibitor, delavirdine improves the pharmacokinetics of indinavir, further strengthening this arm. Given these factors, it is surprising that the delavirdine arm didn't do even better.
Poster 526: Indinavir (IDV), Nevirapine (NVP), Stavudine (d4T) and Lamivudine (3TC) for Amprenavir (APV)-Experienced Subjects -- ACTG 373Amprenavir, the newest of the protease inhibitors, is frequently considered for use in salvage therapy. It may, however, be a useful drug in initial protease therapy. This regimen looks at the "salvage-ability" of an initial amprenavir regimen.
ACTG 347 looked at salvage therapy of patients on initial amprenavir, either as monotherapy (64%) or in combination with two NRTIs, usually AZT/3TC. Patients were treated with a four-drug regimen of indinavir (1,000 mg every eight hours), nevirapine, d4T and 3TC. The median viral load was 15,488, although 20% of the patients were still successfully controlled on the amprenavir regimen. Average T-cell count was 346.
At 48 weeks, 59% of patients were <500 (intent-to-treat analysis; 78% on treatment), with an average T-cell increase of 94. Not surprisingly, those who were undetectable at switch, and those who were on amprenavir monotherapy (therefore with no nucleoside resistance) did even better.
Amprenavir then seems useful not only as a salvage protease inhibitor, but one that can be used first line with a good options for rescue.
This article was provided by The Body PRO. Copyright © Body Health Resources Corporation. All rights reserved.