Long-term comparative effectiveness of pegvaliase versus medical nutrition therapy with and without sapropterin in adults with phenylketonuria.

Phenylketonuria is characterized by intellectual disability and behavioral, psychiatric, and movement disorders resulting from phenylalanine (Phe) accumulation. Standard-of-care treatment involves a Phe-restricted diet plus medical nutrition therapy (MNT), with or without sapropterin dihydrochloride, to reduce blood Phe levels. Pegvaliase is an injectable enzyme substitution treatment approved for adult patients with blood Phe >600 µmol/L despite ongoing management. A previous comparative effectiveness analysis using data from the Phase 3 PRISM trials of pegvaliase (NCT01819727 and NCT01889862) and the Phenylketonuria Demographics, Outcomes and Safety Registry (PKUDOS; NCT00778206) suggested that pegvaliase was more effective at lowering mean blood Phe levels than sapropterin + MNT or MNT alone at 1 and 2 years of treatment. The current work augments and complements the previous analysis by including additional follow-up from the completed studies, robust methods reflecting careful consideration of issues with the distribution of Phe, and alternative methods for adjustment that are important for control of potential confounding in comparative effectiveness. Median blood Phe levels were lower, and median intact protein intakes were higher, in the pegvaliase group (n = 183) than in the sapropterin + MNT (n = 82) and MNT (n = 67) groups at Years 1, 2, and 3. In the pegvaliase group, median blood Phe levels decreased from baseline (1244 µmol/L) to Year 1 (535 µmol/L), Year 2 (142 µmol/L), and Year 3 (167 µmol/L). In the sapropterin + MNT group, median blood Phe levels decreased from baseline (900 µmol/L) to Year 1 (588 µmol/L) and Year 2 (592 µmol/L), and increased at Year 3 (660 µmol/L). In the MNT group, median blood Phe levels decreased slightly from baseline (984 µmol/L) to Year 1 (939 µmol/L) and Year 2 (941 µmol/L), and exceeded baseline levels at Year 3 (1157 µmol/L). The model-estimated proportions of participants achieving blood Phe ≤600 µmol/L were 41%, 100%, and 100% in the pegvaliase group at Years 1, 2, and 3, respectively, compared with 55%, 58%, and 38% in the sapropterin + MNT group and 5%, 16%, and 0% in the MNT group. The estimated proportions of participants achieving more stringent blood Phe targets of ≤360 µmol/L and ≤120 µmol/L were also higher in the pegvaliase group than in the other groups at Years 2 and 3. Overall, our results indicate that, compared with standard therapy, pegvaliase induces a substantial, progressive, and sustained decrease in blood Phe levels - to a much greater extent than sapropterin + MNT or MNT alone - which is expected to improve long-term outcomes in patients with phenylketonuria.

Expert Consensus on the Long-Term Effectiveness of Medical Nutrition Therapy and Its Impact on the Outcomes of Adults with Phenylketonuria.

Many adults with phenylketonuria (PKU) rely on medical nutrition therapy (MNT; low phenylalanine (Phe) diet with protein substitutes/medical foods) to maintain blood Phe concentrations within recommended ranges and prevent PKU-associated comorbidities. Despite disease detection through newborn screening and introduction of MNT as early as birth, adherence to MNT often deteriorates from childhood onwards, complicating the assessment of its effectiveness in the long term. Via a modified Delphi process, consensus (≥70% agreement) was sought on 19 statements among an international, multidisciplinary 13-member expert panel. After three iterative voting rounds, the panel achieved consensus on 17 statements related to the limitations of the long-term effectiveness of MNT (7), the burden of long-term reliance on MNT (4), and its potential long-term detrimental health effects (6). According to the expert panel, the effectiveness of MNT is limited in the long term, is associated with a high treatment burden, and demonstrates that adults with PKU are often unable to achieve metabolic control through dietary management alone, creating an unmet need in the adult PKU population.

Recommendations on phenylketonuria in Turkey.

BACKGROUND: Phenylketonuria (PKU), is an autosomal recessive disease leading to the conversion defect of phenylalanine (Phe) into tyrosine. Severe neurocognitive and behavioral outcomes are observed in untreated cases. The present paper aims to review clinical experiences and expert recommendations in diagnosis, treatment, and follow-up of pediatric PKU patients in Turkey. METHODS: Two advisory board meetings were held in the year 2016 and 2017 with contributions of four leading experts in this field, and an online update meeting was held for final decisions about statements, and conclusions in January 2021. Considering management gaps in diagnosis, treatment, and follow-up of PKU, discussion points are defined. The Committee members then reviewed the Turkish and general literature and the final statements were formulated. RESULTS: The diagnostic cut-off for dried blood spots should remain at 2 mg/dl. Treatment cut-off value is acceptable at 6 mg/dl. Compliance with an ideal follow-up list is strongly recommended. Total protein intake should not be limited. Age-related safe levels of protein intake should be encouraged with an additional 40% from L-amino acids supplements, a 20% compensatory factor to account for the digestibility and utilization of amino acids from the supplement, and a further 20% compensation to optimize Phe control. Cognitive impairment and intelligence quotient evaluations should be performed at least twice before 3 years of age. In pregnant women, the target Phe level should be < 5 mg/dl, and they should be followed-up weekly in the first trimester, then every 2 weeks after organogenesis. Novel pharmacological treatments are promising, but some of them have limitations for our country. CONCLUSIONS: Early diagnosis and treatment initiation; determination and standardization of diagnostic and treatment thresholds; treatment modalities and follow-up parameters are significant steps in treating PKU in the long term. PKU follow-up is a dynamic process with uncertainties and differences in clinical practice.

Genetic etiology and clinical challenges of phenylketonuria.

This review discusses the epidemiology, pathophysiology, genetic etiology, and management of phenylketonuria (PKU). PKU, an autosomal recessive disease, is an inborn error of phenylalanine (Phe) metabolism caused by pathogenic variants in the phenylalanine hydroxylase (PAH) gene. The prevalence of PKU varies widely among ethnicities and geographic regions, affecting approximately 1 in 24,000 individuals worldwide. Deficiency in the PAH enzyme or, in rare cases, the cofactor tetrahydrobiopterin results in high blood Phe concentrations, causing brain dysfunction. Untreated PKU, also known as PAH deficiency, results in severe and irreversible intellectual disability, epilepsy, behavioral disorders, and clinical features such as acquired microcephaly, seizures, psychological signs, and generalized hypopigmentation of skin (including hair and eyes). Severe phenotypes are classic PKU, and less severe forms of PAH deficiency are moderate PKU, mild PKU, mild hyperphenylalaninaemia (HPA), or benign HPA. Early diagnosis and intervention must start shortly after birth to prevent major cognitive and neurological effects. Dietary treatment, including natural protein restriction and Phe-free supplements, must be used to maintain blood Phe concentrations of 120-360 µmol/L throughout the life span. Additional treatments include the casein glycomacropeptide (GMP), which contains very limited aromatic amino acids and may improve immunological function, and large neutral amino acid (LNAA) supplementation to prevent plasma Phe transport into the brain. The synthetic BH4 analog, sapropterin hydrochloride (i.e., Kuvan®, BioMarin), is another potential treatment that activates residual PAH, thus decreasing Phe concentrations in the blood of PKU patients. Moreover, daily subcutaneous injection of pegylated Phe ammonia-lyase (i.e., pegvaliase; PALYNZIQ®, BioMarin) has promised gene therapy in recent clinical trials, and mRNA approaches are also being studied.

Preliminary Investigation of Microbiome and Dietary Differences in Patients with Phenylketonuria on Enzyme Substitution Therapy Compared to Traditional Therapies.

BACKGROUND: Phenylketonuria (PKU) is an inborn error of metabolism that impairs the function of the enzyme phenylalanine hydroxylase. Historical treatment includes limiting dietary phenylalanine (Phe) consumption while supplementing with medical food; however, this treatment has been associated with complications, such as nutritional deficiencies and disruptions in the gut microbiota. OBJECTIVE: The study aim was to compare dietary and gut microbiome differences between adult patients on a traditional PKU diet with those receiving the enzyme substitution therapy Palynziq on a liberalized diet while controlling blood Phe levels to <600 µmol/L (to convert to mg/dL divide by 60.5). DESIGN: A cross-sectional study was conducted comparing patients on a traditional Phe-restricted diet with patients receiving Palynziq eating a liberalized diet. PARTICIPANTS/SETTING: Six patients eating a traditional Phe-restricted diet with medical food and 6 patients on Palynziq eating a liberalized diet without medical food intake for more than 3 years were selected from the University of Kentucky Metabolic Clinic from August to December 2019. MAIN OUTCOME MEASURES: Nutrient intake from 3-day diet records and fecal microbiome taxonomic abundances were analyzed. STATISTICAL ANALYSIS: Mann-Whitney U tests were used for dietary data analysis. Differential abundance analysis for microbiome taxa and pathway data was done using DESeq2 analysis. RESULTS: Dietary data showed patients receiving Palynziq consumed a lower percent of kilocalories from total protein and lower amounts of most micronutrients, but consumed greater amounts of intact protein and cholesterol (P < .05). Microbiome data revealed a greater abundance of the phylum Verrucomicrobia and genus Lachnobacterium in the Traditional group and a greater abundance of the genus Prevotella in the Palynziq group (P < .05). Pathway analysis depicted greater enrichment in carotenoid and amino acid metabolism pathways in the Traditional group (P < .05). Protein (% kcal), dietary fiber (g), fat (% kcal), linolenic acid (% Dietary Reference Intakes), and age were correlated with the underlying microbial community structure for both groups combined. CONCLUSIONS: Patients with PKU treated with Palynziq on a liberalized diet manifest significant differences in diet composition compared with those treated with traditional Phe-restricted diets. Several of these dietary differences may affect the microbiome architecture.

A clínica da similitude / The clinical practice of similarity

Agradecemos a gentileza do convite para proferir esta conferência no interessante momento em que, por iniciativa da comissão organizadora deste XXII Congresso Brasileiro de Homeopatia, são convidados observadores e palestrantes da área não homeopática com a intencionalidade de nos questionar e quebrar a assim chamada auto referência. Trazemos aqui algumas considerações sobre a Clínica da Similitude, que esperamos possam contribuir para a compreensão do nosso modelo e levantar questionamentos sobre a nossa prática. Foi-nos ensinado que a ciência começa na filosofia clássica como um projeto de conhecimento do homem, valendo-se inicialmente apenas da razão, incorporando posteriormente o trabalho experimental para a sua evolução e aperfeiçoamento. Nesse contexto observamos que, como consequência do resgate acidental de Hahnemann, a Homeopatia nasce bem dentro da proposta de experimentação buscando, a seguir, valer-se da razão para tentar compreender o conhecimento que ali se mostrava. (AU)

Improvement of a synthetic live bacterial therapeutic for phenylketonuria with biosensor-enabled enzyme engineering.

In phenylketonuria (PKU) patients, a genetic defect in the enzyme phenylalanine hydroxylase (PAH) leads to elevated systemic phenylalanine (Phe), which can result in severe neurological impairment. As a treatment for PKU, Escherichia coli Nissle (EcN) strain SYNB1618 was developed under Synlogic's Synthetic Biotic™ platform to degrade Phe from within the gastrointestinal (GI) tract. This clinical-stage engineered strain expresses the Phe-metabolizing enzyme phenylalanine ammonia lyase (PAL), catalyzing the deamination of Phe to the non-toxic product trans-cinnamate (TCA). In the present work, we generate a more potent EcN-based PKU strain through optimization of whole cell PAL activity, using biosensor-based high-throughput screening of mutant PAL libraries. A lead enzyme candidate from this screen is used in the construction of SYNB1934, a chromosomally integrated strain containing the additional Phe-metabolizing and biosafety features found in SYNB1618. Head-to-head, SYNB1934 demonstrates an approximate two-fold increase in in vivo PAL activity compared to SYNB1618.

Safety and pharmacodynamics of an engineered E. coli Nissle for the treatment of phenylketonuria: a first-in-human phase 1/2a study.

Phenylketonuria (PKU) is a rare disease caused by biallelic mutations in the PAH gene that result in an inability to convert phenylalanine (Phe) to tyrosine, elevated blood Phe levels and severe neurological complications if untreated. Most patients are unable to adhere to the protein-restricted diet, and thus do not achieve target blood Phe levels. We engineered a strain of E. coli Nissle 1917, designated SYNB1618, through insertion of the genes encoding phenylalanine ammonia lyase and L-amino acid deaminase into the genome, which allow for bacterial consumption of Phe within the gastrointestinal tract. SYNB1618 was studied in a phase 1/2a randomized, placebo-controlled, double-blind, multi-centre, in-patient study ( NCT03516487 ) in adult healthy volunteers (n = 56) and patients with PKU and blood Phe level ≥600 mmol l-1 (n = 14). Participants were randomized to receive a single dose of SYNB1618 or placebo (part 1) or up to three times per day for up to 7 days (part 2). The primary outcome of this study was safety and tolerability, and the secondary outcome was microbial kinetics. A D5-Phe tracer (15 mg kg-1) was used to study exploratory pharmacodynamic effects. SYNB1618 was safe and well tolerated with a maximum tolerated dose of 2 × 1011 colony-forming units. Adverse events were mostly gastrointestinal and of mild to moderate severity. All participants cleared the bacteria within 4 days of the last dose. Dose-responsive increases in strain-specific Phe metabolites in plasma (trans-cinnamic acid) and urine (hippuric acid) were observed, providing a proof of mechanism for the potential to use engineered bacteria in the treatment of rare metabolic disorders.

Characterization of an engineered live bacterial therapeutic for the treatment of phenylketonuria in a human gut-on-a-chip.

Engineered bacteria (synthetic biotics) represent a new class of therapeutics that leverage the tools of synthetic biology. Translational testing strategies are required to predict synthetic biotic function in the human body. Gut-on-a-chip microfluidics technology presents an opportunity to characterize strain function within a simulated human gastrointestinal tract. Here, we apply a human gut-chip model and a synthetic biotic designed for the treatment of phenylketonuria to demonstrate dose-dependent production of a strain-specific biomarker, to describe human tissue responses to the engineered strain, and to show reduced blood phenylalanine accumulation after administration of the engineered strain. Lastly, we show how in vitro gut-chip models can be used to construct mechanistic models of strain activity and recapitulate the behavior of the engineered strain in a non-human primate model. These data demonstrate that gut-chip models, together with mechanistic models, provide a framework to predict the function of candidate strains in vivo.

Psychosocial functioning in children with phenylketonuria: Relationships between quality of life and parenting indicators.

OBJECTIVE: This study aimed to assess the impact of phenylketonuria (PKU) and its treatment on parent and child health-related quality of life (HRQoL) and to identify the parenting-related correlates of parent and child HRQoL, as well as metabolic control. METHODS: Eighteen mothers of 2- to 12-year-old children with PKU participated and completed a series of self-report questionnaires including the PKU Impact and Treatment Quality of Life Questionnaire (PKU-QOL). RESULTS: Mothers reported that the most significant impact of PKU on HRQoL was in relation to the impact of their child's anxiety during blood tests on their own HRQoL and guilt related to poor adherence to dietary restrictions and supplementation regimens. Higher reported intensity of child emotional and behavioural difficulties and parenting stress were associated with higher scores for PKU symptoms on the PKU-QOL, higher scores for emotional, social, and overall impact of PKU, and higher scores for the impact of dietary restriction. Where mothers reported greater use of overreactivity as a parenting strategy, children tended to have better lifetime phenylalanine levels; however, the overall impact of PKU and the impact of supplement administration on mothers' HRQoL were worse for these families. CONCLUSIONS: These findings have implications for a holistic family-centred approach to the care of children with PKU and their families.

A series of three case reports in patients with phenylketonuria performing regular exercise: first steps in dietary adjustment.

Background Phenylketonuria (PKU), a rare, inherited metabolic condition, is treated with a strict low-phenylalanine (Phe) diet, supplemented with Phe-free protein substitute. The optimal nutritional management of a sporting individual with PKU has not been described. Therefore, guidelines for the general athlete have to be adapted. Case presentation Three clinical scenarios of sporting patients with PKU are given, illustrating dietary adaptations to usual management and challenges to attain optimal sporting performance. Therefore, the main objectives of sports nutrition in PKU are to (1) maintain a high carbohydrate diet; (2) carefully monitor hydration status; and (3) give attention to the timing of protein substitute intake in the immediate post-exercise recovery phase. Optimal energy intake should be given prior to, during and post exercise training sessions or competition. Fortunately, a usual low-Phe diet is rich in carbohydrate, but attention is required on the types of special low-protein foods chosen. Acute exercise does not seem to influence blood Phe concentrations, but further evidence is needed. Summary Well-treated PKU patients should be able to participate in sports activities, but this is associated with increased nutritional requirements and dietary adjustments. Conclusions It should be the goal of all sporting patients with PKU to maintain good metabolic Phe control and attain maximal athletic performance.

Adherence to tetrahydrobiopterin therapy in patients with phenylketonuria.

Phenylketonuria (PKU) is an inborn error in phenylalanine metabolism due to deficiency of the enzyme, phenylalanine hydroxylase (PAH). Treatment includes restriction of dietary phenylalanine, and in some individuals, supplementation with the PAH cofactor, tetrahydrobiopterin (sapropterin dihydrochloride). A survey was conducted among patients with PKU who had been prescribed sapropterin to assess reasons for continuing or discontinuing the drug. The primary reason that sapropterin responders discontinued the drug was because of side effects, followed by insufficient reduction of blood phenylalanine and insurance issues. Conversely, those who remained on therapy cited increased tolerance for dietary protein as the main reason for continuation, along with lower blood phenylalanine concentrations and feeling better. This study suggests that adherence to sapropterin therapy is mainly dependent upon the increase in dietary protein allowed when on the drug.

Treatment of phenylketonuria using minicircle-based naked-DNA gene transfer to murine liver.

UNLABELLED: Host immune response to viral vectors, persistence of nonintegrating vectors, and sustained transgene expression are among the major challenges in gene therapy. To overcome these hurdles, we successfully used minicircle (MC) naked-DNA vectors devoid of any viral or bacterial sequences for the long-term treatment of murine phenylketonuria, a model for a genetic liver defect. MC-DNA vectors expressed the murine phenylalanine hydroxylase (Pah) complementary DNA (cDNA) from a liver-specific promoter coupled to a de novo designed hepatocyte-specific regulatory element, designated P3, which is a cluster of evolutionary conserved transcription factor binding sites. MC-DNA vectors were subsequently delivered to the liver by a single hydrodynamic tail vein (HTV) injection. The MC-DNA vector normalized blood phenylalanine concomitant with reversion of hypopigmentation in a dose-dependent manner for more than 1 year, whereas the corresponding parental plasmid did not result in any phenylalanine clearance. MC vectors persisted in an episomal state in the liver consistent with sustained transgene expression and hepatic PAH enzyme activity without any apparent adverse effects. Moreover, 14-20% of all hepatocytes expressed transgenic PAH, and the expression was observed exclusively in the liver and predominately around pericentral areas of the hepatic lobule, while there was no transgene expression in periportal areas. CONCLUSION: This study demonstrates that MC technology offers an improved safety profile and has the potential for the genetic treatment of liver diseases.

Early replacement therapy in a first Japanese case with autosomal recessive guanosine triphosphate cyclohydrolase I deficiency with a novel point mutation.

Autosomal recessive guanosine triphosphate cyclohydrolase I (GTPCH) deficiency is an inborn error of tetrahydrobiopterin (BH4) synthesis from GTP. GTPCH deficiency causes severe reduction of BH4, resulting in hyperphenylalaninemia (HPA) and decreased dopamine and serotonin synthesis. Without treatment, a patient with GTPCH deficiency develops complex neurological dysfunctions, including dystonia and developmental delays. The first Japanese patient with GTPCH deficiency was discovered by HPA during asymptomatic newborn screening. The phenylalanine level at the age of 5days was 1273µmol/L (cutoff value, 180.0µmol/L). The high serum phenylalanine level was decreased to normal after adequate BH4 oral supplementation. Serum and urinary pteridine examination revealed very low levels of neopterin and biopterin. Sequence analysis of GCH1 revealed compound heterozygous point mutations, including a novel point mutation (p.R235W). Replacement therapy with BH4 and L-dopa/carbidopa were started at the age of 1month, and 5-hydroxytryptophan (5-HTP) was started at the age of 5months. At 10months of age, the patient showed slight dystonia but no obvious developmental delay. Cerebrospinal fluid should be examined to determine the appropriate dosage of supplement drugs. In conclusion, it is important to control the serum phenylalanine level and perform early replacement of neurotransmitters to prevent neurological dysfunction.

[Phenylketonuria: new treatments]. / La phénylcétonurie : nouveaux traitements.

Low phenylalanine diet has been the key treatment of phenylketonuria for more than 50years, allowing efficient management of thousands of PKU patients to date. However, non-compliance exists, mainly after adolescence. A medication for PKU received approval in Europe in 2009 (sapropterine dihydrochloride or Kuvan(®)) and can benefit to patients responsive to this drug. Other treatment options are available in some countries (glycomacropeptides, large neutral amino acids) or are currently under investigation (phenylalanine ammonia lyase, chaperones molecules, gene therapy).

Sapropterina no tratamento da hiperfenilalaninemia com deficiência de BH4 / Sapropterin in the treatment of hyperphenylalaninemia with BH4 deficiency

Fenilcetonúria (FNC) é uma doença genética, autossômica recessiva, causada por mutações no gene localizado no cromossomo 12q22-q24, o qual codifica a enzima hepática fenilalanina-hidroxilase (FAH). Sua ausência ou deficiência impede a conversão hepática de fenilalanina (FAL), um dos aminoácidos essenciais e mais comuns do organismo, em tirosina, causando acúmulo de FAL no sangue e em outros tecidos. O aumento de fenilalanina no sangue em 98% dos casos é devido a mutações na codificação genética para a enzima fenilalanina-hidroxilase, enquanto 2% são devidos a defeitos no metabolismo da tetrahidrobiopterina (BH4), que é um cofator essencial para a atividade da fenilalanina-hidroxilase. A principal característica da doença não tratada é retardo mental, com piora durante a fase de desenvolvimento do cérebro e que se estabilizaria com a maturação completa deste órgão. O quociente de inteligência (QI) mede a extensão deste retardo e varia de leve a gravemente prejudicado. A HFA não tratada resulta em progressivo retardo mental, com QI < 50. A piora está relacionada aos níveis sanguíneos de FAL. Caso a doença seja diagnosticada logo após o nascimento e o paciente for mantido em dieta restrita em FAL, os sintomas podem ser prevenidos e a criança pode ter desenvolvimento e expectativa de vidas normais. Nesse sentido, o rastreamento no Brasil é realizado pelo teste do pezinho, cuja necessidade consta no Estatuto da Criança e do Adolescente, e está regulamentado pela portaria que estabeleceu o Programa Nacional de Triagem Neonatal para diagnóstico precoce de fenilcetonúria. No Protocolo Clínico e Diretrizes Terapêuticas do Ministério da Saúde para Fenilcetonúria foram incluídos os pacientes com níveis de FAL≥ 10mg/dl (600 µmol/l) em dieta normal 1,14 e todos os que apresentarem níveis de FAL entre 8 e 10 mg/dl persistentes (pelo menos em 3 dosagens consecutivas, semanais, em dieta normal). Dieta restrita em FAL é eficaz em reduzir os níveis sanguíneos de FAL e melhorar o QI e o prognóstico neuropsicológico dos pacientes com HFA. O tratamento deve ser iniciado tão cedo quanto possível, idealmente até o 10º dia de vida. O aleitamento materno deve ser encorajado e associado ao uso de fórmula isenta de FAL. Os níveis de FAL devem ser diminuídos rapidamente. Além da dieta, o tratamento clínico recomendado pelo PCDT do Ministério da Saúde para o controle metabólico dos pacientes é a utilização de fórmulas alimentares especiais. As fórmulas são medicamentos que devem conter as quantidades recomendadas de vitaminas e sais minerais adequadas à faixa etária do paciente. Sapropterina é uma forma sintética oral de BH4 (BH4 supplementation sapropterin dihydrochloride). Há relatos de casos de pessoas com FCN que apresentaram boa resposta após o uso de doses farmacológicas de BH4, com redução dos níveis de FAL. Todos tinham mutação no gene FAH. Pessoas com resposta ao BH4 são identificadas inicialmente por um teste com teste de tolerância a BH4. Resposta positiva é considerada como uma redução de 30% ou mais na concentração de FAL, 24 horas após a administração de BH4. A variação na intensidade da resposta é independente da gravidade da FCN, da dose de BH4 empregada no teste de tolerância, duração do teste e genótipo. Pessoas com mesmo genótipo mostram respostas diferentes. Há poucos resultados de uso de longa duração de BH4 que mostram que pode haver relaxamento da restrição dietética sem efeitos adversos. A maioria dos indivíduos dos estudos apresentava doença moderada ou leve. A Secretaria-Executiva da CONITEC realizou busca na literatura por artigos científicos, com o objetivo de localizar a melhor evidência científica disponível sobre o tema. A CONITEC em sua 14ª reunião ordinária realizada no dia 04 de abril de 2013, recomendou a não incorporação no SUS da sapropterina para o tratamento de hiperfenilalaninemia (HFA) com deficiência em tetrahidrobiopterina (BH4). Considerou-se que os estudos, a maioria de baixa qualidade metodológica, não conseguiram comprovar a superioridade do tratamento, principalmente no que diz respeito à ausência de dados específicos para o subgrupo com deficiência de BH4. Os membros da CONITEC presentes na 15ª reunião do plenário do dia 09/05/2013 deliberaram, por unanimidade, por não recomendar a sapropterina para o tratamento de hiperfenilalaninemia (HFA) com deficiência em tetrahidrobiopterina (BH4). A Portaria nº 34, de 6 de agosto de 2013 - Torna pública a decisão de não incorporar o medicamento sapropterina no tratamento da hiperfenilalaninemia com deficiência de BH4 no Sistema Único de Saúde (SUS).

[Complications due to receiving incorrect amino acid preparations]. / Complicaties door verwisseling aminozuurpreparaten.

Due to improved diagnostics and care there is an increasing number of adults with inherited metabolic diseases. The best-known example is phenylketonuria. Treatment consists of a disease-specific diet, for example protein restriction supplemented with essential amino acids. However, like prescription drugs, diet preparations can have side effects. This implies that a description of the indications and contra-indications, an assessment of the efficacy and a definition of the desired duration of treatment are required. Mistakes in the delivery of these disease-specific diet preparations by the pharmacy can have severe consequences, as illustrated by three case reports.

Terapias nutricionales novedosas y otros enfoques utilizados en el tratamiento de pacientes con fenilcetonuria / Novel nutritional therapies and others approaches used in the treatment of patients with phenylketonuria / Terapias nutricionais inovadoras e outros enfoques utilizados no tratamento de pacientes com fenilcetonúria

El tratamiento dietético tradicional de los pacientes con fenilcetonuria (PKU) ha constituido, desde sus inicios, ungran éxito para la prevención del retraso mental generado por la acumulación de fenilalanina en la sangre. Sin embargo, la dieta baja en fenilalanina representa una carga que muchas veces dificulta su seguimiento y, a su vez, se le atribuye a estos pacientes cierta deficiencia nutricional. Todo ello constituye uno de los motivos por los cuales se hace necesaria la búsqueda de terapias alternativas que mejoren el pronóstico y la calidad de vida de los pacientes con PKU. Se han desarrollado actualmente diversos enfoques novedosos, tanto desde el punto de vista nutricional como no nutricional. Un ejemplo de ello lo constituye la suplementación de la dieta con amino-ácidos neutros grandes y la utilización de glicomacropéptidos en el desarrollo de alimentos nutricionalmente completos, por el rol que desempeñan en el restablecimiento de los niveles de fenilalanina. Asimismo, la implementación de ácidos grasos polinsaturados de cadena larga tiene un papel importante en el desarrollo neurológico de los pacientes. Adicionalmente, se han desarrollado terapias encaminadas a aumentar o suplantar la actividad de la fenilalanina hidroxilasa, como es el caso de la administración de tetrabiopterina o fenilalanina amonioliasa que representan, para algunos pacientes, una solución alejada de una dieta estricta. Además, investigaciones preclínicas de terapias génicas y celulares para PKU están en curso. El presente trabajo tiene la finalidade de revisar el conocimiento actual sobre las terapias nutricionales novedosas y otros enfoques utilizados en el tratamiento de pacientes con PKU.

The traditional dietary treatment of Phenylketonuria (PKU) has resulted in great success in the prevention of mental retardation caused by the accumulation ofPhenylalanine in the blood. However, patients often find it difficult to follow the low-Phenylalanine diet, which still carries risk of associated nutritional deficiencies. Thisis one of the reasons why it is necessary to seek alternativetherapies that improve the prognosis and quality of life of PKU patients. Several new approaches have recently been developed, both from a dietary and no-dietary point of view. An example of these is the dietary supplementationof large neutral amino acids and the use of glycomacropeptide in the production of nutritionally complete foods, because of the role they play in the restoration of Phenylalanine levels. Furthermore, the introduction of long-chain polyunsaturated fatty acids plays an important role in the patients’ neurological development. Further therapies have been developed that increase or replace the activityof Phenylalanine hydroxylase, such as the administration of Phenylalanine ammonia-lya se or tetrabiopterin, which may offer some patients a solution to a strict diet. In addition, preclinical research of gene and cell-based therapies for the treatment of PKU are underway. The aim of this paper is to review current knowledge about new nutritional therapies and other new approachesused in the treatment of PKU patients.

O tratamento dietético tradicional dos pacientes com fenilcetonúria (PKU) tem constituído, desde o seu começo, um grande sucesso para a prevenção do atraso mental gerado pela acumulação de fenilalanina no sangue. Noentanto, a dieta baixa em fenilalamina representa uma carga que muias vezesdificulta o seu acompanhamento, e por sua vez, atribui-se a estes pacientes certa deficiência nutricional. Tudo isto constitui um dos motivos pelos quais se faz necessária a busca de terapias alternativas que melhorem o prognóstico e a qualidade de vida dos pacientes com PKU. Foram desenvolvidos atualmentediversos enfoques inovadores, tanto a partir do ponto de vista nutricional quanto não nutricional. Um exemplo disso é suplementação da dieta com aminoácidos neuro grandes e a utilização de glimacropéptidos no desenvolvimento de alimentos nutricionalmente completos, pela função que desempanham no restabelecimento dos níveis de fenilalanina. Além disso, a implementação de ácidos graxos polinsaturados de cadeia longa tem um papel importanteno desenvolvimento neurológico dos pacientes. Adicionalmente, foram desenvolvidas terapias encaminhadas para aumentar ou substituit a atividade da fenilalanina hidroxilase, como é o caso da administração de tetrabiopterinaou fenilalanina amonioliasa que representam, para alguns pacientes, uma solução distante de uma dieta estrita. Além disso, pesquisas pré-clínicas de terapias gênicas e celulares para PKU estão em curso. O presentetrabalho tem a finalidade de revisar o conhecimento atual sobre as terapias nutricionais inovadoras e outros enfoques utilizados no tratamento de pacientes com PKU.

Reversal of metabolic and neurological symptoms of phenylketonuric mice treated with a PAH containing helper-dependent adenoviral vector.

Phenylketonuria (PKU) is one of the most common inborn errors of metabolism and is due to a deficit of phenylalanine hydroxylase, the enzyme that converts phenylalanine (Phe) into tyrosine (Tyr). The resultant hyperphenylalaninemia (HPA) leads to severe neurological impairment, whose pathogenesis has not been entirely elucidated. Treatment of PKU consists essentially in lifelong protein restriction and, in mild cases, in tetrahydrobiopterin supplementation. However, compliance to both strategies, particularly to the long-term diet, is low and therefore other therapies are desirable. We explored a gene therapy approach aimed at long-term correction of the pathologic phenotype of BTBR-PahEnu2 mice, a mouse model of PKU. To this aim, we developed a helper-dependent adenoviral (HD-Ad) vector expressing phenylalanine hydroxylase and administered it to 3-week-old PKU mice. This resulted in complete normalization of Phe and Tyr levels and reversal of coat hypopigmentation that lasted throughout the observation period of six months. The spatial learning deficits observed in PKU mice were also reversed and hippocampus levels of the N-methyl-D-Aspartate and 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl) propanoic acid receptor subunits returned to normal. Long-term potentiation, which is impaired in PKU mice, was also restored by treatment. Therefore, HD-Ad vector-mediated gene therapy is a promising approach to PKU treatment.