A 96-week comparison of lopinavir-ritonavir combination therapy followed by lopinavir-ritonavir monotherapy versus efavirenz combination therapy.

Antiretroviral-naive HIV-1-infected volunteers received zidovudine/lamivudine plus either lopinavir/ritonavir (n=104) or efavirenz (n=51). Lopinavir/ritonavir-treated subjects demonstrating 3 consecutive monthly HIV-1 RNA levels <50 copies/mL started lopinavir/ritonavir monotherapy. In previous-failure=failure analysis, 48% (lopinavir/ritonavir) and 61% (efavirenz) maintained HIV-1 RNA at <50 copies/mL through week 96, (P= .17; 95% confidence interval [CI] for the difference, -29% to 4%); in noncompletion=failure analysis, 60% (lopinavir/ritonavir) and 63% (efavirenz) maintained HIV-1 RNA at <50 copies/mL at week 96 (P= .73; 95% CI for the difference, -19% to 13%). Significant sparing of peripheral lipoatrophy was noted in the lopinavir/ritonavir simplification strategy. This study has provided important information for future studies using treatment simplified to lopinavir/ritonavir monotherapy.

T-1249 retains potent antiretroviral activity in patients who had experienced virological failure while on an enfuvirtide-containing treatment regimen.

BACKGROUND: T-1249 is a 39-amino acid synthetic peptide fusion inhibitor (FI) shown to preserve antiretroviral activity in vitro against human immunodeficiency virus (HIV) isolates that have decreased susceptibility to enfuvirtide (ENF). METHODS: A 10-day phase 1/2 study of the safety and antiretroviral activity of T-1249 was conducted in 53 HIV-1-infected adults with detectable viremia while on an ENF-containing treatment regimen. RESULTS: From FI-naive baseline levels, the geometric mean (GM) decrease in susceptibility to ENF was 116.3-fold, and the GM decrease in susceptibility to T-1249 was 2.0-fold. Patients continued to administer their failing treatment regimen but replaced ENF with T-1249 at a dose of 192 mg/day. T-1249 was generally well tolerated; injection site reactions, which were generally mild, were the most commonly reported adverse event (64% of patients). The median change from levels of HIV-1 RNA at baseline to levels on day 11 was -1.26 log(10) copies/mL (95% confidence interval, -1.40 to -1.09 log(10) copies/mL); on day 11, a decrease from baseline HIV-1 RNA levels of >/=1.0 log(10) copies/mL was seen in 73% of patients. Antiretroviral activity, as measured by levels of HIV-1 RNA, was not predicted by baseline susceptibility to T-1249 or to ENF; genotypic substitutions that emerged during T-1249 treatment were identified in virus from some patients. CONCLUSIONS: These results indicate that FIs constitute an expanding class of antiretroviral agents with the potential to be sequenced.

SOLO: 48-week efficacy and safety comparison of once-daily fosamprenavir /ritonavir versus twice-daily nelfinavir in naive HIV-1-infected patients.

OBJECTIVE: To compare the magnitude and durability of the antiviral response to fosamprenavir (FPV) plus ritonavir (RTV) once-daily (FPV/r QD) with nelfinavir twice-daily (NFV BID), each administered with abacavir and lamivudine twice-daily. METHODS: An international, phase III, randomized, open-label study in antiretroviral therapy-naive, HIV-infected adults. RESULTS: Patients with advanced HIV disease received FPV/r QD (n = 322) or NFV BID (n = 327). At week 48, 69% of patients in the FPV/r QD group and 68% in the NFV BID group had plasma HIV-1 RNA (vRNA) < 400 copies/ml, whereas 55% of patients in the FPV/r QD group and 53% in the NFV BID group had vRNA < 50 copies/ml (intent to treat, rebound/discontinuation = failure). More patients in the NFV BID group (17%) experienced virological failure than in the FPV/r QD group (7%). Efficacy of FPV/r QD was maintained in patients with CD4+ cell counts < 50 x 10 cells/l or vRNA >/= 100 000 copies/ml at entry. At week 48, median CD4+ cell counts were increased to 203 x 10 cells/l (FPV/r QD group) and 207 x 10 cells/l (NFV BID group). Both regimens were generally well tolerated. Diarrhea was more common on NFV BID than on FPV/r QD (16 versus 9%; P = 0.008). Fasting lipid profile results were generally favorable in both treatment arms. FPV/r QD maintained plasma amprenavir (APV) trough concentrations above the mean phenotypic drug-susceptibility (IC50) for wild-type virus for APV. CONCLUSION: As a first choice protease inhibitor with a low daily pill burden, FPV/r QD was well tolerated and provided potent, durable antiviral suppression.

Twice-daily Trizivir versus Combivir-abacavir in antiretroviral-experienced adults with human immunodeficiency virus-1 infection: a formulation-switch trial.

STUDY OBJECTIVE: To establish the clinical equivalence (noninferiority) of one tablet containing abacavir 300 mg-lamivudine 150 mg-zidovudine 300 mg (Trizivir) versus a tablet containing lamivudine 150 mg-zidovudine 300 mg (Combivir) given with one abacavir (ABC) 300-mg tablet, administered twice/day, in antiretroviral-experienced, human immunodeficiency virus (HIV)-1-infected patients. DESIGN: Randomized, open-label, parallel-group, multicenter, formulation-switch study. SETTING: Twenty seven outpatient treatment sites. PATIENTS: Adults with HIV-1 RNA levels of 400 copies/ml or less and CD4+ cell counts above 200 cells/mm3 who had been treated for 16 weeks or more with highly active antiretroviral therapy containing Combivir-ABC. INTERVENTION: Patients were randomized 1:1 to Trizivir (97 patients) or Combivir-ABC (98) for 24 weeks. MEASUREMENTS AND MAIN RESULTS: The primary study end point was the proportion of patients who maintained less than a 0.5-log10 increase from baseline in HIV-1 RNA (virologic success) through week 24. Clinical equivalence of the treatments was established if the 95.1% lower confidence limit (LCL) for the difference in proportion of virologic success with Trizivir minus Combivir-ABC was -0.12 or greater. Trizivir was clinically equivalent to Combivir-ABC. The intent-to-treat observed analysis at week 24 with Trizivir and Combivir-ABC showed a similar rate of virologic success (83% [80/97] and 77% [75/98], respectively, 95.1% LCL -0.026), of patients with HIV-1 RNA levels of 400 or fewer copies/ml (99% [82/83] and 93% [77/83], respectively, 95.1% LCL 0.021), and of patients with HIV-1 RNA levels of fewer than 50 copies/ml (89% [74/83] and 77% [64/83], respectively, 95.1% LCL 0.038). The intent-to-treat missing = failure analysis showed comparable results. Changes in CD4+ cell count from baseline, overall mean self-reported adherence (Trizivir 97%, Combivir-ABC 92%), and adverse events did not differ significantly between treatments. No ABC-related hypersensitivity reactions occurred. CONCLUSION: Trizivir was clinically equivalent to Combivir-ABC and may be substituted for the latter to simplify treatment and reduce pill burden.

Tenofovir disoproxil fumarate in nucleoside-resistant HIV-1 infection: a randomized trial.

BACKGROUND: Resistance to antiretroviral agents remains a leading cause of treatment failure for patients infected with HIV-1. OBJECTIVE: To describe the efficacy and safety of tenofovir disoproxil fumarate (tenofovir DF) compared with placebo in patients with detectable viral replication despite current antiretroviral therapy. DESIGN: Randomized, double-blind, placebo-controlled study through 24 weeks. After 24 weeks, all patients received open-label tenofovir DF for the remainder of the 48-week study. SETTING: 75 North American, European, and Australian HIV clinics. PATIENTS: 552 HIV-1-infected adults who were receiving antiretroviral therapy and had stable HIV-1 RNA levels ranging from 400 to 10,000 copies/mL. MEASUREMENTS: Change in HIV-1 RNA level (time-weighted average from baseline through week 24); proportion of patients with grade 3 or 4 laboratory abnormalities and adverse events; and genotypic HIV-1 resistance testing in a separate substudy at baseline, week 24, and week 48. RESULTS: A statistically significant decrease in HIV-1 RNA level through week 24 (the primary end point) was observed in the tenofovir DF group versus the placebo group (-0.61 log10 copies/mL vs. -0.03 log10 copies/mL, respectively [P < 0.001]; difference, -0.58 log10 copies/mL [95% CI, -0.68 to -0.49 log10 copies/mL]). In a virologic substudy, 94% of 253 patients had plasma isolates expressing reverse transcriptase mutations associated with nucleoside resistance mutations at baseline. Through week 24, the incidence of clinical adverse events was similar between patients receiving placebo and those receiving tenofovir DF (14% vs. 13%). No evidence of tenofovir DF-related toxicity was seen through week 48. CONCLUSION: In treatment-experienced patients with suboptimal viral suppression, tenofovir DF significantly reduced HIV-1 RNA level and had a safety profile similar to that of placebo.

Lamivudine 300 mg QD versus continued lamivudine 150 mg BID with stavudine and a protease inhibitor in suppressed patients.

PURPOSE: To compare the efficacy (sustained virologic suppression) and safety/tolerability of a switch to lamivudine 300 mg once daily (QD) versus continued lamivudine 150 mg twice daily (BID) in virologically suppressed patients (HIV-1 RNA <400 copies/mL for > or =3 months) on stable (> or =6 months) therapy with lamivudine 150 mg BID plus stavudine and either indinavir or nelfinavir. METHOD: Eighty-nine suppressed patients > or =18 years old with CD4 counts >50 cells/mm(3) were enrolled in this phase II, open-label, multicenter, randomized, stratified (by pretrial protease inhibitor [PI]), parallel-group clinical trial. Eighty-one patients received either lamivudine 300 mg QD (n = 39) or 150 mg BID (n = 42) with their pretrial stavudine/PI regimens for 24 weeks. RESULTS: A high rate of virologic suppression was sustained with both regimens throughout the trial. At week 24, intent-to-treat:exposed (missing = failure) analyses showed no statistically significant differences in the percentage of patients with HIV-1 RNA <400 copies/mL (95% [QD] vs. 90% [BID]) or <50 copies/mL (82% [QD] vs. 81% [BID]) or in the median change from baseline in CD4 counts (+42 cells/mm(3) [QD] vs. +22 cells/mm(3) [BID]). Both regimens were well tolerated. No patient experienced virologic failure, clinical disease progression, or a drug-related serious adverse event during the trial. Self-reported medication adherence was high in both groups. CONCLUSION: Patients who experience virologic suppression with a regimen of lamivudine 150 mg BID in combination with stavudine/PI can maintain that suppression by continuing their regimen or switching to lamivudine 300 mg QD and continuing the other components. Adverse event profiles were comparable among treatment regimens, and no new safety concerns were raised.

Abacavir expanded access program for adult patients infected with human immunodeficiency virus type 1.

Expanded access programs (EAPs) provide medication to patients with life-threatening, treatment-refractory illnesses before regulatory approval and allow the acquisition of safety information. A 2-part, multisite EAP to evaluate abacavir, a carbocyclic nucleoside reverse-transcriptase inhibitor for use in combination antiretroviral therapy, was conducted. The EAP involved >13,000 adults infected with human immunodeficiency virus type 1 (HIV-1) who no longer responded to commercially available treatment regimens. Part A (open-label trials) examined the efficacy, safety, and tolerance of abacavir, and part B (provision of abacavir through expanded access) assessed only the occurrence of serious adverse events. By month 2 of abacavir-containing treatment, plasma HIV-1 RNA levels decreased by > or =0.5 log(10) in 31.4% of patients, and 5.6% of the patients had HIV-1 RNA levels decrease to <400 copies/mL. Drug-related serious adverse events were reported by 7.7% of patients, the most common of which were nausea, skin rash, diarrhea, malaise or fatigue, and fever. Approximately 4.6% of patients experienced a hypersensitivity reaction that was possibly drug related. Overall, the types and incidences of adverse events reported in the abacavir EAP were similar to those reported in phase 2 and 3 clinical trials evaluating abacavir.