Pharmacokinetics, Safety, and Efficacy of Glecaprevir/Pibrentasvir in Adolescents With Chronic Hepatitis C Virus: Part 1 of the DORA Study.

The pangenotypic regimen of glecaprevir and pibrentasvir (G/P) is approved to treat adults with chronic hepatitis C virus (HCV) infection and has yielded high cure rates in adults in clinical trials. Approved treatment options for pediatrics may include ribavirin. A pangenotypic regimen for pediatric patients remains an unmet need. DORA is an ongoing phase 2/3, nonrandomized, open-label study evaluating the pharmacokinetics (PK), safety, and efficacy of G/P in pediatric patients with chronic HCV. This analysis includes Part 1 of the study, conducted in adolescent patients 12-17 years of age given the adult regimen of G/P (300 mg/120 mg) once daily for 8-16 weeks according to the indication durations used in adults. Patients were either treatment naïve or experienced with interferon-based regimens. The primary PK endpoint was steady-state exposures for glecaprevir and pibrentasvir; the primary efficacy endpoint was sustained virologic response 12 weeks after treatment (SVR12). The secondary efficacy endpoints were on-treatment virologic failure, relapse, and reinfection. Safety and tolerability were monitored. Part 1 enrolled 48 adolescent patients infected with genotypes 1, 2, 3, or 4, of whom 47 were administered G/P. All 47 patients (100%) achieved SVR12. No on-treatment virologic failures or relapses occurred. PK exposures of glecaprevir and pibrentasvir were comparable to exposures in adults. No adverse events (AEs) led to treatment discontinuation, and no serious AEs occurred. Conclusion: Adolescent patients with chronic HCV infection treated with G/P achieved a comparable exposure to adults, 100% SVR12 rate, and safety profile consistent with that in adults. This pangenotypic regimen demonstrated 100% efficacy within the adolescent population in as little as 8 weeks of treatment.

Real-world effectiveness and safety of glecaprevir/pibrentasvir for the treatment of patients with chronic HCV infection: A meta-analysis.

BACKGROUND & AIMS: Glecaprevir/pibrentasvir is approved for treating adults infected with HCV genotypes 1-6. In clinical trials, glecaprevir/pibrentasvir was associated with high rates of sustained virologic response at post-treatment week 12 (SVR12) and was well tolerated. A systematic review and meta-analysis of the real-world effectiveness and safety of glecaprevir/pibrentasvir were undertaken. METHODS: Real-world studies reporting SVR12 in adults with HCV infection (n ≥20) treated with glecaprevir/pibrentasvir were identified in journal publications from January 1, 2017, to February 25, 2019, and congress presentations through April 14, 2019. Random-effects meta-analysis was used to determine SVR12 rates using data from ≥2 cohorts; intention-to-treat (ITT) analyses included patients treated with glecaprevir/pibrentasvir who had SVR12 data available, discontinued early, or were lost to follow-up; modified ITT (mITT) analyses excluded those with non-virologic failure. Naïve pooling was used to calculate adverse event (AE) rates. RESULTS: Overall, 12,531 adults were treated with glecaprevir/pibrentasvir (18 cohorts). Of patients with post-treatment week 12 data, SVR12 rates were 96.7% (95% CI 95.4-98.1) in the ITT population (n = 8,583, 15 cohorts) and 98.1% (95% CI 97.1-99.2) in the mITT population (n = 7,001, 14 cohorts). SVR12 rates were ≥95% across subgroups (HCV genotype, cirrhosis status, treatment history, treatment duration, on-label treatment, and subgroups of interest). AEs were reported in 17.7% (1,271/7,199) of patients (8 cohorts). Serious AEs were reported in 1.0% (55/5,522) of patients (6 cohorts). The most frequent AEs were pruritus, fatigue, and headache. AE-related treatment discontinuations were reported in 0.6% (33/5,595) of patients (6 cohorts). CONCLUSIONS: Consistent with clinical trials, real-world evidence indicates that glecaprevir/pibrentasvir is a well-tolerated and highly effective pangenotypic treatment for a broad range of HCV-infected patients. LAY SUMMARY: It is important to assess treatments for hepatitis C virus (HCV) in the real world, as patient populations tend to be more diverse and potentially less adherent to treatment compared to those in clinical trials. Results from 18 studies performed in real-world clinics were pooled and analyzed to investigate the effectiveness and safety of a direct-acting antiviral combination (glecaprevir/pibrentasvir) in routine clinical practice. This analysis showed that glecaprevir/pibrentasvir is highly effective and well tolerated across all HCV genotypes and patient groups studied. It also showed that results seen in the real world are similar to the results seen in clinical trials, even in patients historically considered more challenging to treat.

Efficacy and safety of glecaprevir/pibrentasvir in renally impaired patients with chronic HCV infection.

BACKGROUND AND AIMS: Chronic hepatitis C virus (HCV) infection increases the risk of incident chronic kidney disease (CKD) and progression to end-stage renal disease (ESRD). Previously available direct-acting antiviral regimens are not approved for patients with advanced CKD across all HCV genotypes. METHODS: EXPEDITION-5 is a phase 3 study to evaluate efficacy and safety of the fixed-dose combination of glecaprevir and pibrentasvir (G/P) for chronic HCV infection (genotype 1 through 6) in adults without cirrhosis or with compensated cirrhosis and with stage 3b, 4 or 5 CKD. Patients received approved duration of G/P according to HCV genotype, cirrhosis status and prior HCV treatment experience. The primary efficacy endpoint was percentage of patients with sustained virologic response at 12 weeks post-treatment (SVR12). RESULTS: Among the 101 patients enrolled in the study, 24% had predialysis CKD and 76% were on dialysis. Eighty-four patients were treated with G/P for 8 weeks, 13 patients for 12 weeks and four patients for 16 weeks. Fifty-five per cent of patients had genotype 1, 27% had genotype 2, 15% had genotype 3 and 4% had genotype 4, and none had genotype 5 or 6 infection. The SVR12 rate was 97% (98/101, 95% confidence interval, 91.6-99.0). No patients experienced virologic failure. Adverse events (AEs) reported in at least 5% of the patients were pruritus, bronchitis, hypertension and generalized pruritus. Serious AEs were reported in 12% of patients; none related to study drug. CONCLUSIONS: G/P treatment yielded high SVR12 rates irrespective of the presence of stage 3b, 4 or 5 CKD. No safety signals were detected. CLINICALTRIALS. GOV IDENTIFIER: This Phase 3 clinical trial was funded by AbbVie and registered with clinicaltrials.gov as NCT03069365 (EXPEDITION-5).

Safety and Pharmacokinetics of Glecaprevir/Pibrentasvir in Adults With Chronic Genotype 1-6 Hepatitis C Virus Infections and Compensated Liver Disease.

BACKGROUND: Untreated, chronic hepatitis C virus (HCV) infection may lead to progressive liver damage, which can be mitigated by successful treatment. This integrated analysis reports the safety, efficacy, and pharmacokinetics (PK) of the ribavirin-free, direct-acting, antiviral, fixed-dose combination of glecaprevir/pibrentasvir (G/P) in patients with chronic HCV genotype 1-6 infections and compensated liver disease, including patients with chronic kidney disease stages 4 or 5 (CKD 4/5). METHODS: Data from 9 Phase II and III clinical trials, assessing the efficacy and safety of G/P treatment for 8-16 weeks, were included. The presence of cirrhosis was determined at screening using a liver biopsy, transient elastography, or serum biomarkers. The objectives were to evaluate safety, the rate of sustained virologic response at post-treatment week 12 (SVR12), and steady-state PK by cirrhosis status. RESULTS: Among 2369 patients, 308 (13%) were Child-Pugh Class A, including 20 with CKD 4/5. Overall, <1% of patients experienced an adverse event (AE) that led to G/P discontinuation or G/P-related serious AEs (SAEs). The most common AEs were headache and fatigue, occurring at similar frequencies with and without cirrhosis. SAEs were more common in patients with CKD 4/5, but all were unrelated to G/P. There were no cases of drug-induced liver injury or clinically relevant hepatic decompensation. SVR12 rates were 96.4% (297/308) with compensated cirrhosis and 97.5% (2010/2061) without cirrhosis. PK analysis demonstrated a 2.2-fold increase in glecaprevir exposure, but not pibrentasvir exposure, in patients with compensated cirrhosis. CONCLUSIONS: G/P was safe and efficacious in patients with compensated liver disease, including those with CKD 4/5. CLINICAL TRIALS REGISTRATION: NCT02243280, NCT02243293, NCT02604017, NCT02640482, NCT02640157, NCT02636595, NCT02642432, NCT02651194, and NCT02446717.

Glecaprevir/Pibrentasvir Treatment in Liver or Kidney Transplant Patients With Hepatitis C Virus Infection.

Well-tolerated, ribavirin-free, pangenotypic hepatitis C virus (HCV) treatments for transplant recipients remain a high priority. Once-daily glecaprevir/pibrentasvir demonstrates high rates of sustained virologic response at 12 weeks posttreatment (SVR12) across all major HCV genotypes (GTs). This trial evaluated the safety and efficacy of glecaprevir/pibrentasvir for patients with chronic HCV GT1-6 infection who had received a liver or kidney transplant. MAGELLAN-2 was a phase 3, open-label trial conducted in patients who were ≥3 months posttransplant. Patients without cirrhosis who were HCV treatment-naive (GT1-6) or treatment-experienced (GT1, 2, 4-6; with interferon-based therapy with or without sofosbuvir, or sofosbuvir plus ribavirin) received glecaprevir/pibrentasvir (300/120 mg) once daily for 12 weeks. The primary endpoint compared the percentage of patients receiving glecaprevir/pibrentasvir with SVR12 to a historic SVR12 rate based on the standard of care. Safety of glecaprevir/pibrentasvir was assessed. In total, 80 liver transplant and 20 kidney transplant patients participated in the trial. Most patients had no or minimal fibrosis (80% had fibrosis scores F0-F1) and were infected with HCV GT1 (57%) or GT3 (24%). The overall SVR12 was 98% (n/N = 98/100; 95% confidence interval, 95.3%-100%), which exceeded the prespecified historic standard-of-care SVR12 threshold of 94%. One patient experienced virologic failure. One patient discontinued because of an adverse event considered to be unrelated to treatment; this patient achieved SVR12. Adverse events were mostly mild in severity, and laboratory abnormalities were infrequent. CONCLUSION: Once-daily glecaprevir/pibrentasvir for 12 weeks is a well-tolerated and efficacious, ribavirin-free treatment for patients with chronic HCV GT1-6 infection who have received a liver or kidney transplant. (ClinicalTrials.gov NCT02692703.) (Hepatology 2018; 00:000-000).

A Phase-I pharmacokinetic, safety and food-effect study on flubentylosin, a novel analog of Tylosin-A having potent anti-Wolbachia and antifilarial activity.

BACKGROUND: The parasitic filariae responsible for onchocerciasis and lymphatic filariasis are host to an endosymbiotic bacterium, Wolbachia, which is essential to the fertility and development of the parasites. We performed a Phase-I pharmacokinetic, safety and food-effect study on single and multiple ascending doses of flubentylosin (ABBV-4083), a macrolide antibacterial with activity against Wolbachia, intended to sterilize and eliminate the parasites. METHODS: Seventy-eight healthy adults were exposed to flubentylosin; 36 were exposed to single ascending 40, 100, 200, 400 or 1000 mg doses; 12 received 1000 mg in the food-effect part; and 30 received multiple ascending daily doses of 100 mg for 7 days, 200 mg for 7 or 14 days, or 400 mg for 7 or 14 days. Twenty-two subjects received placebo. RESULTS: Maximum concentrations (Cmax) of flubentylosin were reached after 1-2 hours, with a half-life < 4 hours at doses ≤ 400 mg. Cmax and AUC increased in a more than dose-proportional manner, with similar exposure after multiple dose administration. The most frequently reported adverse events were nausea (8/78, 10%) and headache (6/78, 8%). Two subjects given a single dose of flubentylosin 1000 mg in the food-effect part experienced reversible asymptomatic ALT and AST elevations at Grade 2 or Grade 4, with no elevation in bilirubin, deemed related to study drug. The effect of food on exposure parameters was minimal. No treatment-related serious adverse events were reported. DISCUSSION: Flubentylosin 400 mg for 14 days was the maximum tolerated dose in this first-in-human, Phase-I study in healthy adults. Based on preclinical pharmacokinetic/pharmacodynamic modeling, flubentylosin 400 mg once daily for 7 or 14 days is expected to be an effective dose. A Phase-II, proof-of-concept study with flubentylosin using these regimens is currently ongoing in patients with onchocerciasis in Africa.

Extrapolation as a Default Strategy in Pediatric Drug Development.

Pediatric drug development lags adult development by about 8 years (Mulugeta et al. in Pediatr Clin 64(6):1185-1196, 2017). In such context, many incentives, regulations, and innovative techniques have been proposed to address the disparity for pediatric patients. One such strategy is extrapolation of efficacy from a reference population. Extrapolation is currently justified by providing evidence in support of the effective use of drugs in children when the course of the disease and the expected treatment response would be sufficiently similar in the pediatric and reference population. This paper's position is that, despite uncertainties, pediatric drug development programs should initially assume some degree of extrapolation. The degree to which extrapolation can be used lies along a continuum representing the uncertainties to be addressed through generation of new pediatric evidence. In addressing these uncertainties, the extrapolation strategy should reflect the level of tolerable uncertainty concerning the decision to expose a child to the risks of a new drug. This judgment about the level of tolerable uncertainty should vary with the context (e.g., disease severity, existing therapeutic options) and can be embedded into pediatric drug development archetypes to ascertain the extent of studies needed and whether simultaneous development for adults and adolescents be considered.

Efficacy and Safety of 8 Weeks of Glecaprevir/Pibrentasvir in Treatment-Naïve, HCV-Infected Patients with APRI ≤ 1 in a Single-Arm, Open-Label, Multicenter Study.

INTRODUCTION: The presence or absence of cirrhosis in patients with chronic hepatitis C virus (HCV) infection influences the type and duration of antiviral therapy. Non-invasive markers, like serum aspartate aminotransferase (AST) to platelet ratio index (APRI), may help identify appropriate HCV treatment-naive patients for 8-week treatment with the pangenotypic regimen of glecaprevir/pibrentasvir. METHODS: This single-arm, open-label, international, prospective study (NCT03212521) evaluated the efficacy and safety of 8-week glecaprevir/pibrentasvir regimen in HCV treatment-naïve adults with chronic HCV genotypes 1-6 infection, APRI ≤ 1, and no prior evidence of cirrhosis. The primary and secondary outcomes were sustained virologic response at 12 weeks post-treatment (SVR12) by modified intent-to-treat (mITT) and intent-to-treat (ITT) analyses, respectively. Additional endpoints included virologic failures, treatment adherence, and genotype-specific SVR12 rates. RESULTS: Among the 230 patients enrolled, most were less than 65 years old (90%); 37% and 43% had a history of injection drug use or psychiatric disorders, respectively. SVR12 rates were 100% (222/222; 95% CI 98.3-100%) and 96.5% (222/230; 95% CI 94.2-98.9%) by mITT and ITT analyses, respectively. There were no virologic failures. ITT SVR12 rates were greater than 94% for all HCV genotypes. In patients with available data, treatment adherence was 99% (202/204). There were no grade 3 or higher laboratory abnormalities in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin, and low rates of serious adverse events (2%). CONCLUSIONS: Glecaprevir/pibrentasvir was highly efficacious and well tolerated in HCV treatment-naïve patients with APRI ≤ 1 and no prior evidence of cirrhosis. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT03212521. FUNDING: AbbVie. Plain language summary available for this article.

Efficacy and safety of glecaprevir/pibrentasvir in patients with chronic hepatitis C virus genotype 5 or 6 infection (ENDURANCE-5,6): an open-label, multicentre, phase 3b trial.

BACKGROUND: The pangenotypic direct-acting antiviral regimen of glecaprevir coformulated with pibrentasvir is approved to treat chronic hepatitis C virus (HCV) genotype 1-6 infection in adults. In registrational studies, 84 (99%) of 85 patients with HCV genotype 5 or 6 infection achieved a sustained virological response (SVR) with glecaprevir/pibrentasvir, with no virological failures. To increase the body of data for these less prevalent genotypes, ENDURANCE-5,6 evaluated the efficacy and safety of glecaprevir/pibrentasvir exclusively in patients infected with HCV genotype 5 or 6. METHODS: ENDURANCE-5,6 was a phase 3b, single-arm, open-label, multicentre trial done in 24 hospitals or clinics in Europe, Oceania, North America, South Africa, and southeast Asia. Adults with chronic HCV genotype 5 or 6 infection who were previously untreated or treatment-experienced were eligible to be enrolled. Glecaprevir/pibrentasvir (300 mg/120 mg) was given orally once daily for 8 weeks (for patients without cirrhosis) or 12 weeks (for patients with compensated cirrhosis). The primary efficacy endpoint was SVR12 (ie, HCV RNA <15 IU/mL at 12 weeks post-treatment), assessed within each HCV genotype, and analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02966795. FINDINGS: Between Feb 9, 2017, and Aug 28, 2018, 84 patients were enrolled: 23 with genotype 5 infection and 61 with genotype 6 infection. Overall, 82 (97·6%, 95% CI 94·4-100·0) of the 84 patients achieved SVR12. 22 (95·7%, 95% CI 87·3-100·0) of 23 patients with genotype 5 infection achieved SVR12, as did 60 (98·4%, CI 95·2-100·0) of 61 with genotype 6 infection. One patient with an HCV genotype 6f infection and cirrhosis had on-treatment virological failure at treatment week 12, and one patient with HCV genotype 5a without cirrhosis who had achieved SVR at post-treatment week 4 relapsed at post-treatment week 12. Five (6%) patients had serious adverse events, none of which were deemed related to glecaprevir/pibrentsavir or led to discontinuation. Fatigue (11 [13%] patients) and headache (11 [13%]) were the only adverse events that occurred in 10% or more of patients. No post-baseline grade 3 or higher increases in aminotransferase concentrations were reported. INTERPRETATION: Glecaprevir/pibrentasvir achieved high SVR12 rates, comparable with data reported in registrational studies, and was well tolerated in patients with HCV genotype 5 or 6 infection with compensated liver disease. FUNDING: AbbVie.

An Innovative, Collaborative, and Strategic Approach to Proactively Evaluate and Update Drug Interactions Based on Prescribing Information of Newly Approved Medicinal Products.

BACKGROUND: Drug-drug interaction (DDIs) are evaluated using pharmacokinetic (PK) simulation models, clinical studies, and scientific publications throughout drug development. DDIs with Norvir (ritonavir) and combination products (eg, Kaletra [lopinavir/ritonavir]) containing ritonavir as a PK enhancer are relevant, because these drugs could affect exposures of CYP3A4 substrates. Application of algorithms proactively identified recently approved drugs, which potentially cause adverse outcomes when given with drugs containing ritonavir. METHODS: An evidence-based medicine technology platform was used to identify newly approved products. PK-related information from the products' prescribing information was reviewed to identify DDIs with ritonavir. Algorithms were used to further evaluate PK, clinical, and postmarketing information pertinent to the interaction to determine if prescribing information required revision. RESULTS: From January 1, 2014, through December 31, 2015, 39 newly approved drugs were identified as having potential interactions with Norvir and/or Kaletra. Ten drugs were excluded, 19 drugs went through initial screening, and 10 drugs underwent in-depth algorithm-based analyses for DDIs. No changes to prescribing information for Norvir or Kaletra were recommended from evaluation of the DDIs. Regulatory concurrence with AbbVie decisions was 93.1% (27/29, 93.1%); in 6.9% (2/29, 6.9%) of the evaluated interactions, at least 1 local regulatory authority disagreed with recommendations, requiring label changes to incorporate the DDI information. CONCLUSIONS: This proactive algorithmic approach identifies and complements existing methods used to detect DDIs with newly approved products. Additionally, this approach facilitates timely communication of risks to patients and healthcare providers via label revisions, publications, or other regulatory communications.

Towards early inclusion of children in tuberculosis drugs trials: a consensus statement.

Children younger than 18 years account for a substantial proportion of patients with tuberculosis worldwide. Available treatments for paediatric drug-susceptible and drug-resistant tuberculosis, albeit generally effective, are hampered by high pill burden, long duration of treatment, coexistent toxic effects, and an overall scarcity of suitable child-friendly formulations. Several new drugs and regimens with promising activity against both drug-susceptible and drug-resistant strains have entered clinical development and are either in various phases of clinical investigation or have received marketing authorisation for adults; however, none have data on their use in children. This consensus statement, generated from an international panel of opinion leaders on childhood tuberculosis and incorporating reviews of published literature from January, 2004, to May, 2014, addressed four key questions: what drugs or regimens should be prioritised for clinical trials in children? Which populations of children are high priorities for study? When can phase 1 or 2 studies be initiated in children? What are the relevant elements of clinical trial design? The consensus panel found that children can be included in studies at the early phases of drug development and should be an integral part of the clinical development plan, rather than studied after regulatory approval in adults is obtained.