Suitability Of Nitisinone In Alkaptonuria 1 (SONIA 1): an international, multicentre, randomised, open-label, no-treatment controlled, parallel-group, dose-response study to investigate the effect of once daily nitisinone on 24-h urinary homogentisic acid excretion in patients with alkaptonuria a... (original) (raw)
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Annals of clinical biochemistry, 2017
Background Alkaptonuria (AKU) is a rare, debilitating autosomal recessive disorder affecting tyrosine metabolism. Deficiency of homogentisate 1,2-dioxygenase leads to increased homogentisic acid (HGA) which is deposited as ochronotic pigment. Clinical sequelae include severe early onset osteoarthritis, increased renal and prostate stone formation and cardiac complications. Treatment has been largely based on analgaesia and arthroplasty. The National AKU Centre in Liverpool has been using 2mg nitisinone (NTBC) off-license for all patients in the United Kingdom with AKU and monitoring the tyrosine metabolite profiles. Methods Patients with confirmed AKU are commenced on 2mg dose (alternative days) of NTBC for three months with daily dose thereafter. Metabolite measurement by LC-MS/MS is performed at baseline, day 4, three-months, six-months and one-year post-commencing nitisinone. Thereafter, monitoring and clinical assessments are performed annually. Results Urine HGA concentration d...
JIMD reports, 2015
Alkaptonuria (AKU) is a serious genetic disease due to a defect in tyrosine metabolism, leading to increased serum levels of homogentisic acid (HGA). Nitisinone decreases HGA in AKU, but the concentration-response relationship has not been previously reported. To determine the relationship between serum concentrations of nitisinone and the effect on both HGA and tyrosine; secondly to determine steady-state pharmacokinetics of nitisinone in AKU patients. Thirty-two patients with AKU received either 1, 2, 4, or 8 mg nitisinone daily. Urine and serum HGA and serum tyrosine and nitisinone were measured during 24 h at baseline (before first dose) and after 4 weeks of treatment. Nitisinone pharmacokinetics (area under the curve [AUC] and maximum concentrations [C max]) were dose proportional. The median oral clearance determined in all patients, irrespective of dose, was 3.18 mL/h·kg (range 1.6-6.7).Nitisinone decreased urinary excretion of HGA in a concentration-dependent manner, with a ...
2015
Lakshminarayan R Ranganath, FRCP(Edin), FRCPath1, Anna M Milan PhD, FRCPath1, Andrew T Hughes MPhil1, John J Dutton FIBMS1, Richard Fitzgerald MRCP2, Michael C Briggs FRCS3, Helen Bygott BSc1, Eftychia E Psarelli MSc4, Trevor F Cox PhD4, James A Gallagher PhD5, Jonathan C Jarvis PhD6, Christa van Kan7, Anthony K Hall MBBS, BSc, AKC8, Dinny Laan MSc7, Birgitta Olsson MSc9, Johan Szamosi MSc9, Mattias Rudebeck MSc, BMedSc9, Torbjörn Kullenberg MD9, Arvid Cronlund MSc9, Lennart Svensson PhD9, Carin Junestrand DDS9, Hana Ayoob BA10, Oliver G Timmis BA10, Nicolas Sireau PhD10, Kim-Hanh Le Quan Sang11, Federica Genovese PhD12, Daniela Braconi PhD13, Annalisa Santucci PhD13, Martina Nemethova MSc14, Andrea Zatkova PhD14, Judith McCaffrey MSc, Peter Christensen PhD, Gordon Ross PhD, Richard Imrich MD, PhD17, Jozef Rovensky17.
Osteoarticular cells tolerate short-term exposure to nitisinone-implications in alkaptonuria
Clinical rheumatology, 2015
Alkaptonuria (AKU) is a rare genetic disease resulting in severe, rapidly progressing, early onset multi-joint osteoarthropathy. A potential therapy, nitisinone, is being trialled that reduces the causative agent; homogentisic acid (HGA) and in a murine model has shown to prevent ochronosis. Little is currently known about the effect nitisinone has on osteoarticular cells; these cells suffer most from the presence of HGA and its polymeric derivatives. This led us to investigate nitisinone's effect on chondrocytes and osteoblast-like cells in an in vitro model. Human C20/A4 immortalized chondrocytes, and osteosarcoma cells MG63 cultured in DMEM, as previously described. Confluent cells were then plated into 24-well plates at 4 × 10(4) cells per well in varying concentrations of nitisinone. Cells were cultured for 7 days with medium changes every third day. Trypan blue assay was used to determine viability and the effect of nitisinone concentration on cells. Statistical analysis w...
Annals of clinical biochemistry, 2015
Alkaptonuria is a rare debilitating autosomal recessive disorder of tyrosine metabolism, where deficiency of homogentisate 1,2-dioxygenase results in increased homogentisic acid. Homogentisic acid is deposited as an ochronotic pigment in connective tissues, especially cartilage, leading to a severe early onset form of osteoarthritis, increased renal and prostatic stone formation and hardening of heart vessels. Treatment with the orphan drug, nitisinone, an inhibitor of 4-hydroxyphenylpyruvate dioxygenase has been shown to reduce urinary excretion of homogentisic acid. A reverse phase liquid chromatography tandem mass spectrometry method has been developed to simultaneously analyse serum homogentisic acid, tyrosine and nitisinone. Using matrix-matched calibration standards, two product ion transitions were identified for each compound (homogentisic acid, tyrosine, nitisinone) and their respective isotopically labelled internal standards ((13)C6-homogentisic acid, d2-tyrosine, (13)C6-...