Dosing regimen optimisation for oseltamivir in immunocompromised paediatric patients with influenza: Extrapolation of efficacy.

AIMS: To optimise the dosing regimen of oseltamivir for immunocompromised (IC) paediatric patients (<18 years) with influenza, we used an extrapolation approach alongside clinical data. METHODS: Efficacy was extrapolated from adult IC patients to paediatric IC patients by leveraging existing efficacy, safety, pharmacokinetic (PK)/pharmacodynamic (PD), and disease-progression models of oseltamivir and oseltamivir carboxylate (OC). Data of IC paediatric patients from two studies (NV25719 and NV20234) were included in the population PK (n = 30), PK/PD analysis (n = 22) and disease modelling approach (n = 36). Simulations were performed to identify the optimal dosing regimen. RESULTS: Clearance of oseltamivir (CL) and OC (CLM ) were similar in IC and otherwise-healthy (OwH) patients <10 years, but decreased by 44.4% (95% CI: 26.8-62.0) and 49.1% (95% CI: 34.5-63.8), respectively, in IC patients aged 10-17 years versus OwH patients. There were no notable exposure-response relationships for any of the virologic PD analyses. Thus, no additional benefit was seen with oseltamivir carboxylate exposures higher than achieved with the conventional dose (75 mg twice daily, age- and weight-adjusted for children <13 years). The disease model illustrated that doses above the conventional oseltamivir dose had limited impact on viral kinetics in IC paediatric patients and a prolonged treatment duration of 10 days was favoured to limit potential viral rebound. CONCLUSION: An oseltamivir dosage recommendation (conventional dose, twice daily for 10 days) was established in IC paediatric patients with influenza, based on extrapolation of efficacy from IC adults, leveraging population PK, PK/PD, and disease modelling, whilst taking resistance and safety data into account.

Pharmacologic effects of oseltamivir in immunocompromised adult patients as assessed by population PK/PD analysis and drug-disease modelling for dosing regimen optimization.

AIM: Pharmacologic effects were analysed to determine a dose recommendation for oseltamivir in immunocompromised (IC) adults with influenza. METHODS: Quantitative clinical pharmacology methods were applied to data from 160 adult IC patients (aged 18-78 years) from two studies (NV20234, 150 patients; NV25118, 10 patients) who received oseltamivir 75-200 mg twice daily for up to 10 days. An established population-pharmacokinetic (PK) model with additional effects on oseltamivir and oseltamivir carboxylate (OC) clearance described the PK characteristics of oseltamivir in IC patients versus otherwise healthy (OwH) patients from previous clinical trials. Estimated PK parameters were used to evaluate exposure-response relationships for virologic endpoints (time to cessation of viral shedding, viral load measures and treatment-emergent resistance). A drug-disease model characterized the viral kinetics of influenza accounting for the effect of OC on viral production. RESULTS: Oseltamivir clearance was 32.5% lower (95% confidence interval [CI], 26.1-38.8) and OC clearance was 33.7% lower (95% CI, 23.2-44.1) in IC versus OwH patients. No notable exposure-response relationships were identified for exposures higher than those achieved after conventional dose oseltamivir 75 mg, which appeared to be close to the maximum effect of oseltamivir. Simulations of the drug-disease model predicted that initiating treatment within 48 hours of symptom onset had maximum impact, and a treatment duration of 10 days was favourable over 3-5 days to limit viral rebound. CONCLUSIONS: Our findings support the use of conventional-dose oseltamivir 75 mg twice daily for 10 days in the treatment of IC adult patients with influenza.

Pharmacokinetics and Pharmacodynamics of Conventional-Dose vs Triple-Dose Oseltamivir in Severely Immunocompromised Children With Influenza.

This randomized phase 1b study evaluated the pharmacokinetics/pharmacodynamics of conventional-dose (30-75 mg twice daily [BID]) vs triple-dose (90-225 mg BID; weight-adjusted) oseltamivir for treatment of influenza in severely immunocompromised children <13 years. Oseltamivir carboxylate (OC) Cmax and AUC0-12h were ~2-fold higher with triple-dose vs conventional-dose oseltamivir. Increased dose/exposure of oseltamivir/OC did not improve virological outcomes or reduce viral resistance. Median time to cessation of viral shedding was similar with triple-dose and conventional-dose oseltamivir (150.7 vs 157.1 hours, respectively); median time to alleviation of baseline fever was longer with conventional-dose oseltamivir (28.4 vs 11.3 hours). No new safety signals were identified.

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.

Two-year Efficacy and Safety of Subcutaneous Tocilizumab in Combination with Disease-modifying Antirheumatic Drugs Including Escalation to Weekly Dosing in Rheumatoid Arthritis.

OBJECTIVE: To evaluate the longterm efficacy and safety of subcutaneous tocilizumab (TCZ-SC) every 2 weeks (q2w) over 2 years in patients with rheumatoid arthritis who have an inadequate response to disease-modifying antirheumatic drugs (DMARD). METHODS: Patients (n = 656) were randomized 2:1 to TCZ-SC 162 mg q2w or placebo-SC q2w plus DMARD. After a 24-week double-blind period, patients (n = 457) were rerandomized to open-label TCZ-SC q2w by means of prefilled syringe or autoinjector. Escape therapy with weekly TCZ-SC was available for patients with inadequate efficacy from Week 12. Maintenance of response and safety to 2 years was assessed. Analyses used nonresponder imputation. RESULTS: The American College of Rheumatology (ACR) 20 response after TCZ-SC was maintained beyond Week 24 and was > 70% at each timepoint. ACR50/70, 28-joint Disease Activity Score remission, and ≥ 0.30 decrease from baseline in the Health Assessment Questionnaire-Disability Index response rates were also maintained after Week 24 in the TCZ-SC arm (≥ 50%, > 25%,> 32% and > 56%, respectively). Following escape for inadequate efficacy, many patients achieved ACR20 at the end of the study, 35% after escape from TCZ-SC, and 63% from placebo. The rates of serious adverse events [(11.20/100 patient-years (PY)] including serious infections (3.25/100 PY) were stable through Week 96. No association between anti-TCZ antibody development and loss of efficacy or adverse events was observed. CONCLUSION: Efficacy and safety of TCZ-SC q2w was maintained up to 2 years and remained comparable with previously published data for intravenous TCZ. Dose escalation to weekly TCZ-SC was associated with ACR responses in prior nonresponders and was well tolerated.

Subcutaneous tocilizumab versus placebo in combination with disease-modifying antirheumatic drugs in patients with rheumatoid arthritis.

OBJECTIVE: The efficacy and safety of subcutaneous tocilizumab (TCZ-SC) versus subcutaneous placebo (PBO-SC) was evaluated in patients with rheumatoid arthritis who had an inadequate response to disease-modifying antirheumatic drugs in the BREVACTA study. METHODS: Patients (n = 656) were randomized 2:1 to receive TCZ-SC 162 mg every other week or PBO-SC every other week for 24 weeks; 20% previously received anti-tumor necrosis factor treatment. Escape therapy with TCZ-SC 162 mg weekly was offered from week 12 for inadequate response. The primary end point was the American College of Rheumatology 20% improvement (ACR20) response at week 24. The key secondary outcomes were radiographic progression and safety. RESULTS: TCZ-SC was superior to PBO-SC for ACR20 response at week 24 (60.9% versus 31.5%; P < 0.0001). All secondary end points showed TCZ-SC to be superior to PBO-SC, including ACR50 and ACR70 response (40% and 20% for TCZ-SC, respectively, and 12% and 5% for PBO-SC, respectively; P < 0.0001 for both) and Disease Activity Score in 28 joints (DAS28) remission (DAS28 <2.6; 32% versus 4% [P < 0.0001]). The mean change in modified Sharp/van der Heijde score was significantly lower in the TCZ-SC group than the PBO-SC group (0.62 versus 1.23; P = 0.0149). Adverse events (AEs) and serious AEs (SAEs) were comparable between the TCZ-SC and PBO-SC groups; 4.6% and 3.7% of patients had at least 1 SAE, respectively, and infection was the most common SAE in 2.1% and 1.8% of patients, respectively. More injection site reactions occurred with TCZ-SC than PBO-SC (7.1% versus 4.1%). No anaphylaxis or serious hypersensitivity reactions occurred. There were 3 deaths in the TCZ-SC group and 0 in the PBO-SC group. CONCLUSION: TCZ-SC every other week had significantly greater efficacy, including ACR end points and inhibition of joint damage, compared with PBO-SC. TCZ-SC was well tolerated and its safety profile was comparable with that of previous intravenous TCZ studies.

Association of four DNA polymorphisms with acute rejection after kidney transplantation.

Renal transplant outcomes exhibit large inter-individual variability, possibly on account of genetic variation in immune-response mediators and genes influencing the pharmacodynamics/pharmacokinetics of immunosuppressants. We examined 21 polymorphisms from 10 genes in 237 de novo renal transplant recipients participating in an open-label, multicenter study [Cyclosporine Avoidance Eliminates Serious Adverse Renal-toxicity (CAESAR)] investigating renal function and biopsy-proven acute rejection (BPAR) with different cyclosporine A regimens and mycophenolate mofetil. Genes were selected for their immune response and pharmacodynamic/pharmacokinetic relevance and were tested for association with BPAR. Four polymorphisms were significantly associated with BPAR. The ABCB1 2677T allele tripled the odds of developing BPAR (OR: 3.16, 95% CI [1.50-6.67]; P=0.003), as did the presence of at least one IMPDH2 3757C allele (OR: 3.39, 95% CI [1.42-8.09]; P=0.006). BPAR was almost fivefold more likely in patients homozygous for IL-10 -592A (OR: 4.71, 95% CI [1.52-14.55]; P=0.007) and twice as likely in patients with at least one A allele of TNF-alpha G-308A (OR: 2.18, 95% CI [1.08-4.41]; P=0.029). There were no statistically significant interactions between polymorphisms, or the different treatment regimens. Variation in genes of immune response and pharmacodynamic/pharmacokinetic relevance may be important in understanding acute rejection after renal transplant.