The cerebro-hepato-renal syndrome of Zellweger is a fatal inherited disease caused by deficient import of peroxisomal matrix proteins. The pathogenic mechanisms leading to extreme hypotonia, severe mental retardation and early death are unknown. We generated a Zellweger animal model through inactivation of the murine Pxr1 gene (formally known as Pex5) that encodes the import receptor for most peroxisomal matrix proteins. Pxr1-/- mice lacked morphologically identifiable peroxisomes and exhibited the typical biochemical abnormalities of Zellweger patients. They displayed intrauterine growth retardation, were severely hypotonic at birth and died within 72 hours. Analysis of the neocortex revealed impaired neuronal migration and maturation and extensive apoptotic death of neurons.

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Objectives: The aim of this study is to conduct an analysis on the regulation and application of managed entry agreements (MEA) for oncology drugs across different European countries.Methods: Literature search and document analysis were performed between September 2015 and June 2016 to collect information on the regulatory framework and practice of MEA in Belgium, The Netherlands, Scotland, England and Wales, Sweden, Italy, Czech Republic and France. An overview of the content and typology of MEA applied for oncology drugs between 2008 and 2015 was generated based on publically available sources and contributions by national health authorities. Semi-structured interviews were conducted with representatives of national health authorities involved in the management or negotiation of MEA.Results: The application of MEA differs across countries and across different indications for the same drug. Financial based agreements are prevailing due to their simplicity compared to performance-based agreements. Performance-based agreements are less commonly applied in the European countries except for Italy. In the Netherlands, application of performance-based agreements was stopped due to their inability to deal with dynamics in the market, which is highly relevant for oncology drugs.Conclusions: MEA constitute a common policy tool that public payers in European countries use to ensure early access to highly priced oncology drugs. In light of strengths and weaknesses observed for MEA and the expected developments in the oncology area, the importance of MEA is likely to grow in the future.

Peroxisomal beta-oxidation is involved in the degradation of long chain and very long chain fatty acyl-(coenzyme A)CoAs, long chain dicarboxylyl-CoAs, the CoA esters of eicosanoids, 2-methyl-branched fatty acyl-CoAs (e.g. pristanoyl-CoA), and the CoA esters of the bile acid intermediates di- and trihydroxycoprostanic acids (side chain of cholesterol). In the rat, straight chain acyl-CoAs (including the CoA esters of dicarboxylic fatty acids and eicosanoids) are beta-oxidized via palmitoyl-CoA oxidase, multifunctional protein-1 (which displays 2-enoyl-CoA hydratase and L-3-hydroxyacyl-CoA dehydrogenase activities) and peroxisomal thiolase. 2-Methyl-branched acyl-CoAs are degraded via pristanoyl-CoA oxidase, multifunctional protein-2 (MFP-2) (which displays 2-enoyl-CoA hydratase and D-3-hydroxyacyl-CoA dehydrogenase activities) and sterol carrier protein-X (SCPX; displaying 2-methyl-3-oxoacyl-CoA thiolase activity). The side chain of the bile acid intermediates is shortened via one cycle of beta-oxidation catalyzed by trihydroxycoprostanoyl-CoA oxidase, MFP-2 and SCPX. In the human, straight chain acyl-CoAs are oxidized via palmitoyl-CoA oxidase, multifunctional protein-1, and peroxisomal thiolase, as is the case in the rat. The CoA esters of 2-methyl-branched acyl-CoAs and the bile acid intermediates, which also possess a 2-methyl substitution in their side chain, are shortened via branched chain acyl-CoA oxidase (which is the human homolog of trihydroxycoprostanoyl-CoA oxidase), multifunctional protein-2, and SCPX. The rat and the human enzymes have been purified, cloned, and kinetically and stereochemically characterized. 3-Methyl-branched fatty acids such as phytanic acid are not directly beta-oxidizable because of the position of the methyl-branch. They are first shortened by one carbon atom through the a-oxidation process to a 2-methyl-branched fatty acid (pristanic acid in the case of phytanic acid), which is then degraded via peroxisomal beta-oxidation. In the human and the rat, alpha-oxidation is catalyzed by an acyl-CoA synthetase (producing a 3-methylacyl-CoA), a 3-methylacyl-CoA 2-hydroxylase (resulting in a 2-hydroxy-3-methylacyl-CoA), and a 2-hydroxy-3-methylacyl-CoA lyase that cleaves the 2-hydroxy-3-methylacyl-CoA into a 2-methyl-branched fatty aldehyde and formyl-CoA. The fatty aldehyde is dehydrogenated by an aldehyde dehydrogenase to a 2-methyl-branched fatty acid while formyl-CoA is hydrolyzed to formate, which is then converted to CO2. The activation, hydroxylation and cleavage reactions, and the hydrolysis of formyl-CoA are performed by peroxisomal enzymes; the aldehyde dehydrogenation remains to be localized whereas the conversion of formate to CO2 occurs mainly in the cytosol.

In the third step of the ␣-oxidation of 3-methyl-branched fatty acids such as phytanic acid, a 2-hydroxy-3-methylacyl-CoA is cleaved into formyl-CoA and a 2-methyl-branched fatty aldehyde. The cleavage enzyme was purified from the matrix protein fraction of rat liver peroxisomes and identified as a protein made up of four identical subunits of 63 kDa. Its activity proved to depend on Mg 2؉ and thiamine pyrophosphate, a hitherto unrecognized cofactor of ␣-oxidation. Formyl-CoA and 2-methylpentadecanal were identified as reaction products when the purified enzyme was incubated with 2-hydroxy-3-methylhexadecanoyl-CoA as the substrate. Hence the enzyme catalyzes a carbon-carbon cleavage, and we propose calling it 2-hydroxyphytanoyl-CoA lyase. Sequences derived from tryptic peptides of the purified rat protein were used as queries to recover human expressed sequence tags from the databases. The composite cDNA sequence of the human lyase contained an ORF of 1,734 bases that encodes a polypeptide with a calculated molecular mass of 63,732 Da. Recombinant human protein, expressed in mammalian cells, exhibited lyase activity. The lyase displayed homology to a putative Caenorhabditis elegans protein that resembles bacterial oxalyl-CoA decarboxylases. Similarly to the decarboxylases, a thiamine pyrophosphate-binding consensus domain was present in the C-terminal part of the lyase.