Gary Richmond

Safety and Efficacy of Dolutegravir in Treatment-Experienced Subjects With Raltegravir-Resistant HIV Type 1 Infection: 24-Week Results of the VIKING Study

Background. Dolutegravir (DTG; S/GSK1349572), a human immunodeficiency virus type 1 (HIV-1) integrase inhibitor, has limited cross-resistance to raltegravir (RAL) and elvitegravir in vitro. This phase IIb study assessed the activity of DTG in HIV-1–infected subjects with genotypic evidence of RAL resistance. Methods. Subjects received DTG 50 mg once daily (cohort I) or 50 mg twice daily (cohort II) while continuing a failing regimen (without RAL) through day 10, after which the background regimen was optimized, when feasible, for cohort I, and at least 1 fully active drug was mandated for cohort II. The primary efficacy end point was the proportion of subjects on day 11 in whom the plasma HIV-1 RNA load decreased by ≥0.7 log10 copies/mL from baseline or was <400 copies/mL. Results. A rapid antiviral response was observed. More subjects achieved the primary end point in cohort II (23 of 24 [96%]), compared with cohort I (21 of 27 [78%]) at day 11. At week 24, 41% and 75% of subjects had an HIV-1 RNA load of <50 copies/mL in cohorts I and II, respectively. Further integrase genotypic evolution was uncommon. Dolutegravir had a good, similar safety profile with each dosing regimen. Conclusion. Dolutegravir 50 mg twice daily with an optimized background provided greater and more durable benefit than the once-daily regimen. These data are the first clinical demonstration of the activity of any integrase inhibitor in subjects with HIV-1 resistant to RAL.

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.

Long-term safety and effects of tesamorelin, a growth hormone-releasing factor analogue, in HIV patients with abdominal fat accumulation.

Objective:Treatment of HIV patients with daily tesamorelin, a growth hormone-releasing factor analogue, for 26 weeks resulted in a significant decrease in visceral adipose tissue (VAT) and improvement in lipids. The objective of the 26-week extension phase was to evaluate long-term safety and effects of tesamorelin. Design:HIV patients with central fat accumulation in the context of antiretroviral therapy were randomized to tesamorelin 2 mg (n = 273) or placebo (n = 137) s.c. daily for 26 weeks. At week 26, patients originally on tesamorelin were rerandomized to 2 mg tesamorelin (T–T group, n = 154) or placebo (T–P group, n = 50), whereas patients originally on placebo were switched to tesamorelin (P–T group, n = 111). Methods:Safety included adverse events and glucose parameters. Results:Tesamorelin was generally well tolerated. The prevalence of adverse events and serious adverse events during the extension phase was comparable with the initial phase. Changes in glucose parameters over 52 weeks were not clinically significant and similar to those after 26 weeks. The change in VAT was sustained at −18% over 52 weeks of treatment (P < 0.001 versus baseline) as was the change in triglycerides (−51 mg/dl, P < 0.001 versus baseline). Similar sustained beneficial effects were seen for total cholesterol, but high-density lipoprotein decreased minimally over 52 weeks. Upon discontinuation of tesamorelin, VAT reaccumulated. Conclusion:Treatment with tesamorelin was generally well tolerated and resulted in sustained decreases in VAT and triglycerides over 52 weeks without aggravating glucose. Though effects on VAT are sustained during treatment for 52 weeks, these effects do not last beyond the duration of treatment.

Once-Daily Abacavir/Lamivudine and Ritonavir-Boosted Atazanavir for the Treatment of HIV-1 Infection in Antiretroviral-Naïve Patients: A 48-Week Pilot Study

Abstract Purpose: To assess the efficacy and safety of a once-daily (QD) regimen consisting of the co-formulation of abacavir/lamivudine (ABC/3TC) and atazanavir plus ritonavir (ATV-RTV) in antiretroviral (ART)-naïve patients with plasma HIV-1 RNA >5,000 copies/mL. Method: This open-label, multicenter study conducted between September 2004 and June 2006 included 112 patients who received ABC 600 mg/3TC 300 mg and ATV 300 mg-RTV 100 mg QD. Drug switches were permitted for ABC hypersensitivity and ATV-related hyperbilirubinemia. Primary endpoints were proportion of patients achieving HIV-1 RNA <50 copies/mL at Week 48 and treatment discontinuation due to study drugs. Results: A total of 111 patients were treated. At Week 48, the proportion of patients achieving HIV-1 RNA <50 copies/mL was 77% (85/111) by intent-to-treat (ITT) missing=failure, switch included response rate. Drug substitutions occurred in 8 (7%) patients for suspected ABC hypersensitivity reaction (HSR) and in 6 (5%) patients for ATV-related toxicities; only 1 patient discontinued study due to ABC HSR. Four patients met confirmed virologic nonresponse (HIV RNA ⩾400 copies/mL). Treatment-emergent drug resistance was rare, and no patient had virus that developed reduced susceptibility to ATV. Median change from baseline (95% confidence interval) in fasting lipids at Week 48 was 39 (26–66) mg/dL for triglycerides, 28 (22–38) mg/dL for total cholesterol (C), 14 (10.5–16) mg/dL for HDL-C, and 8 (2–16.5) mg/dL for LDL-C. Conclusion: ABC/3TC and ATV-RTV QD is an effective and well-tolerated regimen in ART-naïve patients through 48 weeks, with a modest impact on fasting lipids.

Enfuvirtide Does Not Require Dose Adjustment in Patients With Chronic Kidney Failure: Results of a Pharmacokinetic Study of Enfuvirtide in Hiv-1-infected Patients With Impaired Kidney Function

Objective:The aim of this study was to examine the influence of kidney disease and hemodialysis on the pharmacokinetics of enfuvirtide. Design:An open-label, multicenter, parallel group study of HIV-1-infected patients with varying degrees of kidney dysfunction. Methods:A 90-mg dose of enfuvirtide was administered by subcutaneous injection to 3 groups of patients: group A, patients with normal kidney function; group B, patients with chronic kidney disease; and group C, patients with end-stage renal disease (ESRD) requiring dialysis. Patients with ESRD requiring dialysis received the 90-mg dose of enfuvirtide on 2 separate occasions; a dialysis day and a nondialysis day. After each dose, a full 48-hour pharmacokinetic profile was collected and pharmacokinetic parameters were estimated using model-independent techniques. Results:Enfuvirtide area under the curve (AUC∞) and maximum observed enfuvirtide plasma concentration (Cmax) for patients with normal kidney function (group A) was 49.6 μg·h/mL and 3.79 μg/mL, respectively. Patients with chronic kidney disease (group B) had higher AUC∞ (80.3 μg·h/mL) and Cmax (5.72 μg/mL), which was similar to patients with ESRD (group C) on both nondialysis days (AUC∞ 71.1 μg·h/mL; Cmax 5.34 μg/mL) and dialysis days (AUC∞ 66.9 μg·h/mL; Cmax 6.31 μg/mL). An average of <13% of enfuvirtide was removed during the dialysis procedure. The incidence of adverse events was comparable for all study groups. Conclusion:Enfuvirtide exposure observed in patients with ESRD requiring dialysis or chronic kidney disease was slightly higher than in patients with normal kidney function and similar to historical Cmax and AUC values from studies in patients with normal kidney function. Thus, enfuvirtide does not require dosage adjustment in patients with impaired kidney function.

Pharmacodynamic Effects of Zidovudine 600 mg Once/Day versus 300 mg Twice/Day in Therapy‐Naïve Patients Infected with Human Immunodeficiency Virus

Study Objective. To compare the virologic activity of zidovudine monotherapy administered as 600 mg once/day versus 300 mg twice/day.

Pharmacokinetics, pharmacodynamics and safety of once-daily versus twice-daily dosing with enfuvirtide in HIV-infected subjects

Objective:To investigate the pharmacokinetics, safety/tolerability and antiviral activity of enfuvirtide administered once-daily (QD) versus. twice-daily (BID). Design:An open-label, randomized, multiple dose, two-period crossover study comparing 180 mg enfuvirtide, two injections QD versus 90 mg enfuvirtide, two injections, BID. Methods:Steady-state intensive pharmacokinetic samples were obtained on days 7 and 14. Results:Thirty-seven subjects received at least one dose of enfuvirtide. Thirty-three subjects completed both dosing periods. The regimens were bioequivalent based on the ratio of geometric mean area under the curve (AUC)0–τ [112 ± 6.2 μg· h/ml QD; 115 ± 6.4 μg·h/ml 2 × BID; QD/BID 0.98; 90% confidence interval (CI) 0.89,1.07]. The maximum observed plasma concentration within a dosing interval (Cmax) was 49% higher for QD (9.5 ± 2.7 μg/ml) versus BID (6.3 ± 1.7 μg/ml) and the pre-dose plasma concentration (Ctrough) was 57% lower for QD (1.6 ± 1.1 μg/ml) versus BID (3.8 ± 1.3 μg/ml). The LSM decrease in viral load from baseline to day 7 was 1.0 ± 0.14 log10 (n = 18) for QD and 1.4 ± 0.2 log10 (n = 17) for BID (LSM difference 0.385; P = 0.07). Linear regression analysis suggested that decline in viral load up to day 7 was associated with Ctrough but not Cmax or AUC. There were no significant differences in adverse events between the two dosing regimens. Conclusions:Administration of enfuvirtide 180 mg QD results in bioequivalence compared with 90 mg BID based on AUC with a similar short-term safety profile, but a trend towards a weaker antiretroviral effect. Larger and longer-term studies are needed to determine if 180 mg once daily is an effective dosing alternative for enfuvirtide.