Antibiotic Safety and Effectiveness in Premature Infants With Complicated Intraabdominal Infections.

BACKGROUND: In premature infants, complicated intraabdominal infections (cIAIs) are a leading cause of morbidity and mortality. Although universally prescribed, the safety and effectiveness of commonly used antibiotic regimens have not been established in this population. METHODS: Infants ≤33 weeks gestational age and <121 days postnatal age with cIAI were randomized to ≤10 days of ampicillin, gentamicin, and metronidazole (group 1); ampicillin, gentamicin, and clindamycin (group 2); or piperacillin-tazobactam and gentamicin (group 3) at doses stratified by postmenstrual age. Due to slow enrollment, a protocol amendment allowed eligible infants already receiving study regimens to enroll without randomization. The primary outcome was mortality within 30 days of study drug completion. Secondary outcomes included adverse events, outcomes of special interest, and therapeutic success (absence of death, negative cultures, and clinical cure score >4) 30 days after study drug completion. RESULTS: One hundred eighty infants [128 randomized (R), 52 nonrandomized (NR)] were enrolled: 63 in group 1 (45 R, 18 NR), 47 in group 2 (41 R, 6 NR), and 70 in group 3 (42 R, 28 NR). Thirty-day mortality was 8%, 7%, and 9% in groups 1, 2, and 3, respectively. There were no differences in safety outcomes between antibiotic regimens. After adjusting for treatment group and gestational age, mortality rates through end of follow-up were 4.22 [95% confidence interval (CI): 1.39-12.13], 4.53 (95% CI: 1.21-15.50), and 4.07 (95% CI: 1.22-12.70) for groups 1, 2, and 3, respectively. CONCLUSIONS: Each of the antibiotic regimens are safe in premature infants with cIAI. CLINICAL TRIAL REGISTRATION: NCT0199499.

Population pharmacokinetics of olanzapine in children.

AIMS: The aim of this study was to evaluate the population pharmacokinetics (PopPK) of olanzapine in children and devise a model-informed paediatric dosing scheme. METHODS: The PopPK of olanzapine was characterized using opportunistically collected plasma samples from children receiving olanzapine per standard of care for any indication. A nonlinear mixed effect modelling approach was employed for model development using the software NONMEM (v7.4). Simulations from the developed PopPK model were used to devise a paediatric dosing scheme that targeted comparable plasma exposures to adolescents and adults. RESULTS: Forty-five participants contributed 83 plasma samples towards the analysis. The median (range) postnatal age and body weight of participants were 3.8 years (0.2-19.2) and 14.1 kg (4.2-111.7), respectively. The analysis was restricted to pharmacokinetic (PK) samples collected following enteral administration (oral and feeding tube). A one-compartment model with linear elimination provided an appropriate fit to the data. The final model included the covariates body weight and postmenstrual age (PMA) on apparent olanzapine clearance (CL/F). Typical CL/F and apparent volume of distribution (scaled to 70 kg) were 16.8 L/h (21% RSE) and 663 L (13% RSE), respectively. Developed dosing schemes used weight-normalized doses for children ≤6 months postnatal age or <15 kg and fixed doses for children ≥15 kg. CONCLUSION: We developed a paediatric PopPK model for enterally-administered olanzapine. To our knowledge, this analysis is the first study to characterize the PK of olanzapine in participants ranging from infants to adolescents. Body weight and PMA were identified as influential covariates for characterizing developmental changes in olanzapine apparent clearance.

Approaches to Research Determination of Late Acute Cellular Rejection in Pediatric Liver Transplant Recipients.

A central pathology or site reading of biopsy slides is used in liver transplant clinical trials to determine rejection. We evaluated interrater reliability of readings of "rejection or not" using digitized slides from the Medication Adherence in Children who had a Liver Transplant (MALT) study. Four masked experienced pathologists read the digitized slides and then reread them after a study-specific histologic endpoint development program. Agreement was expressed throughout as a Kappa or Fleiss Kappa statistic (Ò¡). A Ò¡ > 0.6 was predefined as desirable. Readings were correlated with immunosuppressant adherence (the Medication Level Variability Index, [MLVI]), and maximal liver enzyme levels during the study period. Interrater agreement between site and central review in MALT, and between 4 pathologists later on, was low (Ò¡ = 0.44, Fleiss Ò¡ = 0.41, respectively). Following the endpoint development program, agreement improved and became acceptable (Ò¡ = 0.71). The final reading was better-aligned with maximal gamma-glutamyl transferase levels and MLVI as compared with the original central reading. We found substantial disagreement between experienced pathologists reading the same slides. A unique study-specific procedure improved interrater reliability to the point it was acceptable. Such a procedure may be indicated to increase reliability of histopathologic determinations in future research, and perhaps also clinically.

Safety of Metronidazole in Late Pre-term and Term Infants with Complicated Intra-abdominal Infections.

BACKGROUND: Metronidazole is frequently used off-label in infants with complicated intra-abdominal infections (cIAI) to provide coverage against anaerobic organisms, but its safety and efficacy in this indication are unknown. METHODS: In the Antibiotic Safety in Infants with Complicated Intra-Abdominal Infections open-label multicenter trial infants ≥34 weeks gestation at birth and <121 days postnatal age with cIAIs were administered metronidazole as part of multimodal therapy. Metronidazole safety was evaluated by reporting of adverse events (AEs) and safety events of special interest. Cure from disease was determined by blood cultures and a clinical cure score >4. A blinded adjudication committee reviewed all safety events of special interest. RESULTS: Fifty-five infants were included, median gestational age was 36 weeks (range: 34-41) and postnatal age was 7 days (0-63). The most common additional antibiotics received included gentamicin, piperacillin-tazobactam, ampicillin and vancomycin. Only one AE, a candidal rash, was identified to be potentially caused by metronidazole administration. One infant died of cardiopulmonary failure, which was deemed unrelated to metronidazole. The most common events of special interest included feeding intolerance in 18 (33%) infants, and exploratory laparotomy in 10 (18%) requiring intestinal anastomosis in 7 (13%) infants. There was 1 (2%) intestinal stricture. Fifty-three infants (96%) achieved overall therapeutic success, 54 (98%) were alive through 30 days post-study therapy, and 54 (98%) had 30-day clinical cure score >4. CONCLUSIONS: In a cohort of late pre-term and term infants with cIAIs, combination antibiotic therapy that included metronidazole was safe, and therapeutic success was high.

Population Pharmacokinetics of Metoclopramide in Infants, Children, and Adolescents.

Metoclopramide is commonly used for gastroesophageal reflux. The aims of the present study were to develop a pediatric population pharmacokinetic (PopPK) model, which was applied to simulate the metoclopramide exposure following dosing used in clinical practice. Opportunistic pharmacokinetic data were collected from pediatric patients receiving enteral or parenteral metoclopramide per standard of care and these data were simultaneously fitted using NONMEM. Allometric scaling with body weight was included a priori in the model. Using the final model, the steady-state maximum concentrations (Css,max ) and the area under the metoclopramide plasma concentration-time curve at steady state from 0 to 6 hours (AUCss,0-6h ) were simulated following 0.1 or 0.15 mg/kg orally every 6 hours in virtual patients, and compared with previously reported ranges associated with toxicity or the efficacy for gastroesophageal reflux in infants. A two-compartment model with first-order absorption best characterized 87 concentration measurements from 50 patients (median [range] postnatal age of 8.89 years [0.01-19.13]). There were 20 infants (≤ 2 years), 9 children (2 years to age ≤ 12 years), and 21 adolescents (> 12 years). Body weight was the only covariate included in the final model. For > 75% of virtual patients, simulated Css,max and AUCss,0-6h estimates were within the range associated with efficacy for gastroesophageal reflux in infants; however, slightly lower exposures were predicted in virtual patients < 2 years. Our study suggests that a metoclopramide enteral dose of 0.1 mg/kg every 6 hours, which was previously recommended for pediatric patients, results in simulated exposure generally within suggested ranges for the treatment of gastroesophageal reflux.

Improved Outcomes for Liver Transplantation in Patients with Biliary Atresia Since Pediatric End-Stage Liver Disease Implementation: Analysis of the Society of Pediatric Liver Transplantation Registry.

OBJECTIVE: To identify changes in demographics, outcomes, and risk factors for patient and graft loss in patients with biliary atresia undergoing liver transplantation since Pediatric End-Stage Liver Disease implementation (2002). STUDY DESIGN: Demographics and outcomes were compared between patients enrolled in the Society of Pediatric Liver Transplantation registry before (n = 547) and after (n = 1477) 2002. Kruskal-and χ2 Wallis tests identified significant differences between eras. Risk factors for patient and graft loss after 2002 were determined by Cox regression model analysis of time to event data. RESULTS: Significant patient differences after 2002 support increasing disease severity including more status 1 patients and those with a derived Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease score of greater than 30 awaiting transplant. Both patient and graft survival improved after 2002 from 90% to 97% and 81% to 90%, respectively (primary transplant; P < .0001). Significant differences in complications within 30 days included reduced relisting for transplant, rejection, culture-positive infection, repeat operation, hepatic artery thrombosis, portal vein thrombosis, and death/transplant before discharge. Multivariable analysis identified deceased technical variant vs whole graft and retransplantation predictive for patient death, hazard ratios of 4.041 and 8.308, respectively. Deceased technical variant vs whole graft (hazard ratio, 1.963) and donor age 0-5 months vs 1-17 years (hazard ratio, 5.525) were risk factors for graft loss. CONCLUSIONS: The overall outcomes of patients receiving liver transplantation for patients with biliary atresia have improved since 2002 despite evidence of increased disease severity at the time of transplant. Risk factors impacting post-transplant morbidity and mortality in patients with biliary atresia are now mainly surgical including donor variables.

The impact of caregiver post-traumatic stress and depressive symptoms on pediatric transplant outcomes.

PTSS as well as symptoms of depression have been reported in children who experience a serious medical adversity as well as their caretakers. The adverse effects of PTSS, when experienced by the patients, on medical outcomes have been clearly documented. However, the impact of those symptoms, if any, when experienced by the caretakers on child outcomes has not been investigated prospectively. We evaluated whether caregiver PTSS and depression symptoms predict adherence to medications and medical outcomes in a prospective multisite study. Four hundred children participated in MALT. Caretaker PTSS were assessed by the IES and depressive symptoms by CES-D. During 2 years of follow-up, the MLVI was used to determine adherence. Centrally read, biopsy-confirmed organ rejection was the primary medical outcome. IES scores were not associated with either adherence or rejection outcomes. In contrast, there were significant correlations between CES-D (depression) scores and lower adherence, r = .13, P < .001, and a trend toward higher scores on the CES-D among those whose children had experienced rejection, 12.4 (SD = 10.9) versus 9.1 (SD = 8.6), P = .077. Caregivers' PTSS were not a risk factor for poor child outcomes in this cohort, whereas depression symptoms were associated with non-adherence and possibly increased rates of rejection. Further study can validate if caregivers' depression as opposed to PTSS confers greater risk and should be a focus during the clinical care of medically ill children.

Dosing of Continuous Fentanyl Infusions in Obese Children: A Population Pharmacokinetic Analysis.

Differences in fentanyl pharmacokinetics (PK) between obese and nonobese adults have previously been reported; however, the impact of childhood obesity on fentanyl PK is relatively unknown. We developed a population pharmacokinetic (PopPK) model using opportunistically collected samples from a cohort of predominately obese children receiving fentanyl per the standard of care. Using a probability-based approach, we evaluated the ability of different continuous infusion strategies to provide steady-state concentrations (Css ) within an analgesic concentration range (1-3 ng/mL). Fifty-three samples from 32 children were used for PopPK model development. Median (range) age and body weight of study participants were 13 years (2-19 years) and 52 kg (16-164 kg), respectively. The majority of children (94%) were obese. A 2-compartment model allometrically scaled by total body weight provided an appropriate fit to the data. Estimated typical clearance was 32.5 L/h (scaled to 70 kg). A fixed dose rate infusion of 1 µg/kg/h was associated with probabilities between 49% and 58% for achieving Css within target; however, the risk of achieving Css > 3 ng/mL increased with increasing body weight (15% at 16 kg vs 43% at 164 kg). A proposed model-based infusion strategy maintained consistent probabilities across the examined weight range for achieving Css within (58%) and above (20%) target. Use of an allometric relationship between weight and clearance was appropriate for describing the PK of intravenous fentanyl in our cohort of predominately obese children. Our proposed model-derived continuous infusion strategy maximized the probability of achieving target Css in children of varying weights.

Society of pediatric liver transplantation: Current registry status 2011-2018.

BACKGROUND: SPLIT was founded in 1995 in order to collect comprehensive prospective data on pediatric liver transplantation, including waiting list data, transplant, and early and late outcomes. Since 2011, data collection of the current registry has been refined to focus on prospective data and outcomes only after transplant to serve as a foundation for the future development of targeted clinical studies. OBJECTIVE: To report the outcomes of the SPLIT registry from 2011 to 2018. METHODS: This is a multicenter, cross-sectional analysis characterizing patients transplanted and enrolled in the SPLIT registry between 2011 and 2018. All patients, <18 years of age, received a first liver-only, a combined liver-kidney, or a combined liver-pancreas transplant during this study period. RESULTS: A total of 1911 recipients from 39 participating centers in North America were registered. Indications included biliary atresia (38.5%), metabolic disease (19.1%), tumors (11.7%), and fulminant liver failure (11.5%). Greater than 50% of recipients were transplanted as either Status 1A/1B or with a MELD/PELD exception score. Incompatible transplants were performed in 4.1%. Kaplan-Meier estimates of 1-year patient and graft survival were 97.3% and 96.6%. First 30 days of surgical complications included reoperation (31.7%), hepatic artery thrombosis (6.3%), and portal vein thrombosis (3.2%). In the first 90 days, biliary tract complications were reported in 13.6%. Acute cellular rejection during first year was 34.7%. At 1 and 2 years of follow-up, 39.2% and 50.6% had normal liver tests on monotherapy (tacrolimus or sirolimus). Further surgical, survival, allograft function, and complications are detailed.

Population Pharmacokinetics of Doxycycline in Children.

Doxycycline is a tetracycline-class antimicrobial labeled by the United States (U.S.) Food and Drug Administration for children >8 years of age for many common childhood infections. Doxycycline is not labeled for children ≤8 years of age, due to the association between tetracycline class antibiotics and tooth staining, although doxycycline may be used off-label in severe conditions. Accordingly, there is a paucity of pharmacokinetic (PK) data to guide dosing in children 8 years and younger. We leveraged opportunistically-collected plasma samples after intravenous (IV) and oral doxycycline doses received per standard of care to characterize the PK of doxycycline in children of different ages, and evaluated the effect of obesity and fasting status on PK parameters.We developed a population PK model of doxycycline using data collected from 47 patients 0-18 years of age, including 14 participants ≤8 years. We developed a 1 compartment PK model and found doxycycline clearance to be 3.32 L/h/70 kg and volume to be 96.8 L/70kg for all patients; comparable to values reported in adults. We estimated a bioavailability of 89.6%, also consistent with adult data. Allometrically scaled clearance and volume of distribution did not differ between children 2 to ≤8 years of age and children >8 to ≤18 years of age, suggesting that younger children may be given the same per kg dosing. Obese and fasting status were not selected for inclusion in the final model. Additional doxycycline PK samples collected in future studies may be used to improve model performance and maximize its clinical value.