Etude de la relation concentration - effet de l'infliximab et de la conséquence de l'arrêt d'une immunosuppression dans une cohorte de patients pédiatriques avec maladie inflammatoire chronique intestinale

TOURS-BU Médecine (372612103) / SudocSudocFranceF

Efficacy and safety of BH4 before the age of 4 years in patients with mild phenylketonuria.

International audienceBACKGROUND: Sapropterin dihydrochloride, an EMEA-approved synthetic formulation of BH4, has been available in Europe since 2009 for PKU patients older than 4 years, but its use with younger children is allowed in France based on an expert recommendation. We report the cases of 15 patients treated under the age of 4 years and demonstrate the safety and efficacy of this treatment for patients in this age group. PATIENTS AND METHOD: We report the use of BH4 in 15 PKU patients treated before the age of 4 years. RESULTS: Fifteen patients were enrolled in this retrospective study. Mean phenylalaninemia at diagnosis was 542±164 μM and all patients had mild PKU (maximal phenylalaninemia: 600-1200 μM). BH4 responsiveness was assessed using a 24-hour BH4 loading test (20 mg/kg), performed during the neonatal period (n = 11) or before 18 months of age (n = 4). During the test, these patients exhibited an 80±12% decrease in phenylalaninemia. Long-term BH4 therapy was initiated during the neonatal period (n = 7) or at the age of 13±12 months (n = 8). The median duration of treatment was 23 months [min 7; max 80]. BH4 therapy drastically improved dietary phenylalanine tolerance (456±181 vs 1683±627 mg/day, p < 0.0001) and allowed a phenylalanine-free amino acid mixture to be discontinued or not introduced in 14 patients. Additionally, in the eight patients treated after a few months of diet therapy, BH4 treatment significantly decreased mean phenylalaninemia (352±85 vs 254±64μM, p < 0.05), raised the percentage of phenylalaninemia tests within therapeutic targets [120-300 μM] (35±25 vs 64±16%, p < 0.05), and reduced phenylalaninemia variance (130±21 vs 93±27μM, p < 0.05). No side effects were reported. CONCLUSION: BH4-therapy is efficient and safe before the age of 4 years in mild PKU, BH4-responsive patients

Modeling Immunization To Infliximab in Children With Crohn’s Disease Using Population Pharmacokinetics: A Pilot Study

International audienceBackground - Antidrug antibodies (ADAs) dramatically increase infliximab clearance and are responsible for underexposure to the drug, leading to treatment failure. This pilot study aimed at developing a population pharmacokinetic model to detect and describe an early increase in infliximab clearance due to ADA. Methods - Twenty children with Crohn's disease (CD) were followed for 1 year or until treatment failure. Infliximab trough concentration, ADA, C-reactive protein (CRP), and Paediatric Crohn's Disease Activity Index (PCDAI) were recorded at each visit. A time-varying clearance population pharmacokinetic model was built to detect and describe an increase in infliximab clearance, independent from ADA testing. Factors associated with clearance variation and the relationships between infliximab concentrations, clearance variation, and clinical response were investigated. Results - The model detected important increases in clearance in 4 patients. These patients had suboptimal early response, with higher mean PCDAI (P = 0.0086) and CRP (P = 0.028) compared with other patients. Two of them had detectable ADA. Clearance increase as described by the model and lower infliximab trough concentration at week 2 were associated with poorer outcomes in a multivariate Cox model (P = 0.001 and P = 0.0048, respectively). Conclusions - Being able to detect an increase in infliximab clearance, this model could allow the early detection of immunization to infliximab and therefore could help with dose adjustment in patients with CD. Moreover, the results suggest that clearance variations could be used as a predictive marker of clinical response. These findings need to be confirmed in a larger cohort, however, and predictive factors of clearance increase have to be investigated