Cynthia Wat

Durable efficacy of enfuvirtide over 48 weeks in heavily treatment-experienced HIV-1-infected patients in the T-20 versus optimized background regimen only 1 and 2 clinical trials.

Background:The T-20 Versus Optimized Background Regimen Only (TORO) 1 and TORO 2 clinical trials are open-label, controlled, parallel-group, phase 3 studies comparing enfuvirtide plus an optimized background (OB) of antiretrovirals (n = 661) with OB alone (n = 334) in treatment-experienced HIV-1-infected patients. Methods:The primary objective at week 48 was to investigate durability of efficacy, as measured by the percentage of patients maintaining their week 24 response or improving. Efficacy analyses used the intent-to-treat population. Results:A total of 73.7% of patients randomized to the enfuvirtide group remained on treatment through week 48 versus 21.3% originally randomized to the control group. At week 48, a higher proportion of week 24 responders maintained their response or were new responders in the enfuvirtide group than in the control group in each responder category: HIV-1 RNA level ≥1.0 log10 change from baseline, <400 copies/mL and <50 copies/mL (37.4%, 30.4%, and 18.3% in the enfuvirtide group vs. 17.1%, 12.0%, and 7.8% in the control group, respectively; P < 0.0001 for all comparisons). CD4 cell count increases from baseline were twice as great in the enfuvirtide group as in the control group. Conclusion:These data demonstrate durable efficacy of enfuvirtide plus OB over 48 weeks.

Pharmacokinetics of Enfuvirtide in a Patient with Impaired Renal Function

Enfuvirtide is the first member of the fourth class of antiretroviral drugs to become available. We present a case report of a human immunodeficiency virus (HIV)-positive patient with mild renal impairment who developed severe renal impairment secondary to tenofovir therapy while receiving enfuvirtide. Because the patients pharmacokinetic profile was not significantly altered, compared with that of HIV-infected patients with normal renal function, no dose modifications were required.

Safety, tolerability, and pharmacokinetics of ribavirin in hepatitis C virus-infected patients with various degrees of renal impairment.

ABSTRACT Ribavirin (RBV) is an integral part of standard-of-care hepatitis C virus (HCV) treatments and many future regimens under investigation. The pharmacokinetics (PK), safety, and tolerability of RBV in chronically HCV-infected patients with renal impairment are not well defined and were the focus of an open-label PK study in HCV-infected patients receiving RBV plus pegylated interferon. Serial RBV plasma samples were collected over 12 h on day 1 of weeks 1 and 12 from patients with moderate renal impairment (creatinine clearance [CLCR], 30 to 50 ml/min; RBV, 600 mg daily), severe renal impairment (CLCR, <30 ml/min; RBV, 400 mg daily), end-stage renal disease (ESRD) (RBV, 200 mg daily), or normal renal function (CLCR, >80 ml/min; RBV, 800 to 1,200 mg daily). Of the 44 patients, 9 had moderately impaired renal function, 10 had severely impaired renal function, 13 had ESRD, and 12 had normal renal function. The RBV dose was reduced because of adverse events (AEs) in 71% and 53% of severe and moderate renal impairment groups, respectively. Despite this modification, patients with moderate and severe impairment had 12-hour (area under the concentration-time curve from 0 to 12 h [AUC0–12]) values 36% (38,452 ng · h/ml) and 25% (35,101 ng · h/ml) higher, respectively, than those with normal renal function (28,192 ng · h/ml). Patients with ESRD tolerated a 200-mg daily dose, and AUC0–12 was 20% lower (22,629 ng · h/ml) than in patients with normal renal function. PK modeling and simulation (M&S) indicated that doses of 200 mg or 400 mg alternating daily for patients with moderate renal impairment and 200 mg daily for patients with severe renal impairment were the most appropriate dose regimens in these patients.

Evaluation of pharmacokinetics, user handling, and tolerability of peginterferon alfa-2a (40 kDa) delivered via a disposable autoinjector device.

Background Peginterferon alfa-2a (40 kDa) is currently administered using a prefilled syringe. The peginterferon alfa-2a disposable autoinjector is a new safety-engineered device designed to facilitate injection and reduce the risk of needlestick injuries. The analysis of two open-label Phase I trials evaluated the pharmacokinetics, successful administration, and tolerability of peginterferon alfa-2a when using the autoinjector. The studies were performed to support the filing and registration of the autoinjector device. Methods In trial 1, 50 healthy adult subjects received one 180 μg dose of peginterferon alfa-2a via the autoinjector. Serial blood samples were collected predose, up to 336 hours following drug administration, and at follow-up (28 ± 3 days post-dosing) for noncompartmental pharmacokinetic analysis. Trial 2 randomized 60 adult patients with chronic hepatitis C to 180 μg peginterferon alfa-2a once weekly by the autoinjector or prefilled syringe for 3 weeks followed by the alternative device (prefilled syringe or autoinjector, respectively) for 3 weeks. Patients also received ribavirin. Administration by the devices was evaluated under direct observation by a study staff member and by patient subjective assessment. Results In trial 1, following a single dose of peginterferon alfa-2a, the maximum plasma concentration was 16.1 ± 5.3 ng/mL (mean ± standard deviation), and area under the concentration time curve (0–168 hours) was 1996 ± 613 ng · hour/mL, similar to that reported using a vial/syringe or prefilled syringe. In trial 2, few patients showed handling difficulties with either device. Generally, patients were observed to be more satisfied and confident, followed instructions better, and successfully initiated injection with the autoinjector versus the prefilled syringe. Patients reported the autoinjector to be more convenient and easier to use. No pain or discomfort was experienced using the autoinjector. The autoinjector safety profile was consistent with that known for peginterferon alfa-2a/ribavirin. Conclusion These results indicate that peginterferon alfa-2a can be successfully and safely delivered via the autoinjector and that the device is easy to handle.

Children treated with pegylated interferon alfa-2a±ribavirin for chronic hepatitis c

Objectives: No long-term data have been published on the durability of response following pegylated interferon (PegIFN) treatment in children with chronic hepatitis C. This prospective, multicenter, long-term follow-up (LTFU) study aimed to assess long-term durability of sustained virological response (SVR), long-term safety and tolerability, and the association between IL28B genotype and treatment response, in children previously treated with PegIFN alfa-2a ± ribavirin (RBV) in the PEDS-C trial. Methods: A total of 93 patients were assessed for enrollment, and 38 enrolled in the study. Patients attended 2 study visits: 5 (mean 5.6, range 4.1–6.6) and 6 (6.6, 5.1–7.7) years after treatment cessation. Standardized medical history, physical examination, and laboratory testing were performed at these visits. Reminder telephone calls were conducted at 4 and 8 months after the initial visit. Results: The LTFU cohort was the representative of the original PEDS-C cohort because both baseline and treatment characteristics were comparable. Of the 38 participants, 21 achieved SVR (responders) during the PEDS-C trial and 17 had not (nonresponders). All 21 responders maintained undetectable hepatitis C virus RNA during the LTFU (4.4–7.0 years after achieving SVR) in contrast to the nonresponders who demonstrated persistent viremia. IL28B CC genotype was associated with SVR (67% vs 30% in non-CC, P = 0.028). Conclusion: Long-term durability of SVR is excellent following PegIFN alfa-2a treatment in children with chronic hepatitis C; SVR is higher in those with IL28B CC versus non-CC.

Long-Term Growth Outcomes in Children Treated for Chronic Hepatitis C

Effects on linear growth were noted in children treated with peginterferon ± ribavirin in the Pediatric Study of Hepatitis C trial. Growth was further examined in a subset of patients followed for up to 6 years post-treatment. No long-term effects on height-for-age z scores were observed that could be attributed to hepatitis C virus treatment.

Adherence to Enfuvirtide and Its Impact on Treatment Efficacy

High adherence rates to antiretroviral (ARV) therapy are associated with increased durability of viral suppression and decreased rates of drug resistance. The requirement of twice-daily subcutaneous self-administration of enfuvirtide (ENF) has raised concerns about adherence. This study assesses adherence to ENF and an optimized background (OB) of ARVs and its impact on virological and immunological responses during the TORO trials. Eighty-eight percent of patients in the OB arm reported > or = 85% adherence versus 87% of patients in the ENF + OB arm. Higher overall adherence was associated with improved virological and immunological response in both treatment arms at 48 weeks. In patients with > or = 85% adherence, 33% of patients in the ENF + OB arm achieved HIV-1 RNA < 400 copies/ml, versus 13% in the OB arm (p < 0.0001). Similarly, patients with > or = 85% adherence in the ENF + OB arm achieved a mean increase in CD4 cell count of 104 cells/mm(3) compared with 58 cells/mm(3) for patients in the OB arm (p < 0.001). None of the demographic factors explored (age, gender, race) or baseline characteristics (CD4 count, viral load, or baseline sensitivity score) was significant in predicting adherence to ENF when analyzed by multiple regression. Importantly, a history of intravenous drug use (IDU) was not associated with a significant decrease in adherence (mean adherence for IDU 96% versus mean adherence for non-IDU 96%; p = 0.825). Adherence was high in patients receiving the self-injectable ARV enfuvirtide. In addition, the inclusion of ENF did not negatively impact adherence to the ARV regimen as a whole.

Serum HBV RNA as a Predictor of Peginterferon Alfa-2a Response in Patients With HBeAg-Positive Chronic Hepatitis B

Background Hepatitis B virus (HBV) RNA is a novel serum biomarker that has the potential to predict treatment response in patients with chronic hepatitis B. We explored whether HBV RNA serum levels can predict hepatitis B e antigen (HBeAg) seroconversion in patients treated with peginterferon alfa-2a. Methods Serum samples from HBeAg-positive patients previously treated with peginterferon alfa-2a in 2 large randomized controlled trials were retrospectively analyzed. HBV RNA levels were measured using a real-time polymerase chain reaction assay. Ability of individual biomarkers to predict HBeAg seroconversion at 24 weeks posttreatment was evaluated using receiver operating characteristics (ROC) analyses. Results The study included 131 subjects (70% male, 96% Asians, 35% HBV genotypes B, and 61% C), 76 treated with peginterferon alfa-2a alone and 55 in combination with lamivudine. Median HBV RNA levels were significantly lower, at all timepoints, in patients achieving HBeAg seroconversion. Levels of HBV RNA at treatment weeks 12 and 24 showed good ability to predict HBeAg seroconversion (area under ROC scores >0.75, P < .001). A HBV RNA cutoff of >5.5 log10 copies/mL identified 30% of nonresponders at week 12 (negative predictive value >90%). Conclusion Serum HBV RNA is an early predictor of HBeAg seroconversion in patients treated with peginterferon alfa-2a. Clinical Trials Registration NCT01705704.

Efficacy and Safety of Peginterferon Alfa-2a (40KD) in Children with Chronic Hepatitis B: The PEG-B-ACTIVE Study.

Children with chronic hepatitis B (CHB) represent an area of unmet medical need, attributed to increased lifetime risk of CHB sequelae and limited therapeutic options compared with adult CHB patients. The PEG‐B‐ACTIVE (NCT01519960) phase III study evaluated peginterferon (PegIFN) alfa‐2a treatment in children aged 3 to <18 years with CHB. A total of 161 hepatitis B e antigen (HBeAg)‐positive immune‐active patients without advanced fibrosis (AF)/cirrhosis were randomized (2:1) to PegIFN alfa‐2a (Group A, n = 101) or no treatment (Group B, n = 50); patients with AF were assigned to PegIFN alfa‐2a (Group C, n = 10). PegIFN alfa‐2a was administered for 48 weeks by body surface area (BSA) category, based on 180 μg/1.73 m2. HBeAg seroconversion rates at 24 weeks posttreatment were significantly higher in Group A (25.7% vs. 6%; P = 0.0043), as were the rates of hepatitis B surface antigen (HBsAg) clearance (8.9% vs. 0%; P = 0.03), hepatitis B virus (HBV) DNA <2,000 IU/mL (28.7% vs. 2.0%; P < 0.001) or undetectable (16.8% vs. 2.0%; P = 0.0069), and alanine aminotransferase (ALT) normalization (51.5% vs. 12%; P < 0.001). Safety, including incidence of ALT flares and neutropenia, was comparable to the established PegIFN alfa‐2a profile in HBV‐infected adults or hepatitis C virus‐infected children. Changes in growth parameters were minimal during treatment and comparable to those in untreated patients. Safety and efficacy outcomes in Group C were in line with Group A. Conclusion: PegIFN alfa‐2a treatment of children in the immune‐active phase of CHB was efficacious and well tolerated, and associated with higher incidence of HBsAg clearance than in adults. This represents an important advance to the treatment options for children with CHB.

1093 POPULATION PHARMACOKINETIC (PK) ANALYSIS OF RIBAVIRIN (COPEGUS) IN CHRONIC HEPATITIS C (CHC) PATIENTS WITH CHRONIC KIDNEY DISEASE (CKD) LEADS TO CHANGES IN RECOMMENDED DOSING

Methods: A total number of 74 treatment-naive patients with HCV1 was included and randomly assigned to either the bezafibrate group (A, N= −38) or a placebo group (B, N = −36). Group A was pre-treated with 400mg bezafibrate daily for 16 weeks followed by 48 weeks of PR and 400mg bezafibrate per day. Group B was given 400mg of placebo daily for 16 weeks and was then treated with PR and 400mg placebo for 48 weeks. Follow-up was done until 24 weeks after end of treatment. Clinical, hematological, biochemical and virological data were recorded in the pre-treatment, the treatment and the follow-up period. Results: Viral load in the pre-treatment phase did not differ significantly between both groups. Viral kinetic modeling showed that there were no significant differences in interferon treatment efficacy between both groups (p > 0.2). Although the fitted curves of viral kinetics were highly similar, the bezafibrate group had lower HCV-RNA at begin of antiviral treatment. RVR rates were 18.4% (bezafibrate group) and 11.1% (placebo group). cEVR rate in the bezafibrate group was 55.3%, whereas in the placebo group, 41.7% of patients reached cEVR. Additionally, there was a significant negative correlation between screening GGT levels and treatment efficacy (r = −0.28, p = 0.023). Conclusions: Pre-treatment GGT values seem to have an impact on antiviral treatment efficacy and the application of bezafibrate prior to antiviral therapy led to a significant reduction in GGT levels and also some reduction in viral load.