Efficacy and safety of givosiran for acute hepatic porphyria: 24-month interim analysis of the randomized phase 3 ENVISION study.

BACKGROUND & AIMS: Upregulation of hepatic delta-aminolevulinic acid synthase 1 with accumulation of potentially toxic heme precursors delta-aminolevulinic acid and porphobilinogen is fundamental to the pathogenesis of acute hepatic porphyria. AIMS: evaluate long-term efficacy and safety of givosiran in acute hepatic porphyria. METHODS: Interim analysis of ongoing ENVISION study (NCT03338816), after all active patients completed their Month 24 visit. Patients with acute hepatic porphyria (≥12 years) with recurrent attacks received givosiran (2.5 mg/kg monthly) (n = 48) or placebo (n = 46) for 6 months (double-blind period); 93 received givosiran (2.5 mg or 1.25 mg/kg monthly) in the open-label extension (continuous givosiran, n = 47/48; placebo crossover, n = 46/46). Endpoints included annualized attack rate, urinary delta-aminolevulinic acid and porphobilinogen levels, hemin use, daily worst pain, quality of life, and adverse events. RESULTS: Patients receiving continuous givosiran had sustained annualized attack rate reduction (median 1.0 in double-blind period, 0.0 in open-label extension); in placebo crossover patients, median annualized attack rate decreased from 10.7 to 1.4. Median annualized days of hemin use were 0.0 (double-blind period) and 0.0 (open-label extension) for continuous givosiran patients and reduced from 14.98 to 0.71 for placebo crossover patients. Long-term givosiran led to sustained lowering of delta-aminolevulinic acid and porphobilinogen and improvements in daily worst pain and quality of life. Safety findings were consistent with the double-blind period. CONCLUSIONS: Long-term givosiran has an acceptable safety profile and significantly benefits acute hepatic porphyria patients with recurrent attacks by reducing attack frequency, hemin use, and severity of daily worst pain while improving quality of life.

Systemic lupus erythematosus and hydroxychloroquine-related acute intermittent porphyria.

Porphyrias, particularly acute intermittent porphyria (AIP), are rare disorders which could be associated with systemic lupus erythematosus (SLE). Although the association with AIP has been known since 1952, only 11 cases have been published to date. It is widely known that precipitating causes such as infections, hormonal changes, sunlight exposure, stress and drugs could provoke an AIP crisis. Hydroxychloroquine (HCQ) is usually used in lupus patients, but rarely appears to trigger AIP crises even in SLE patients. The case of a 51-year-old man in whom AIP onset was probably due to hydroxychloroquine use during SLE management is presented. SLE onset was accompanied by fever, pleural, lung and joint involvement with a characteristic SLE autoantibody panel. Although prednisone was given, the joint symptoms did not subside. HCQ was then started; however, some days later the patient suffered anxiety, vomiting and severe abdominal pain refractory to pain-relief drugs and liver function had worsened. No cutaneous lesions were observed. The patient suffered similar episodes accompanied by paralytic ileus and dark-coloured urine, the sediment of which showed no abnormalities. In addition, no myoglobinuria was found. This finding raised the suspicion of AIP and urine tests revealed elevated values of delta-aminolevulinic acid and porphobilinogen. Hydroxychloroquine was preventively suspended and the patient improved notably within a few days. In the following months, the patient suffered no relapse and the prednisone dose could be lowered. Finally, a review of the literature on this topic highlighted the exceptional nature of an API/ SLE association particularly in men. Interestingly, porphyria may present first followed by SLE, or vice versa. The latency period between drug administration and disease onset varies from days to 2 years. Both chloroquine and HCQ may induce PAI in SLE patients. Clinicians should be alerted to a possible association with AIP when a patient with SLE recently put on HCQ presents acute onset of abdominal and/or neurological symptoms and dark urine. Appropriate tests and prompt HCQ cessation are mandatory.

Characterization of the hepatic transcriptome following phenobarbital induction in mice with AIP.

Acute Intermittent Porphyria (AIP), an autosomal dominant hepatic disorder, results from hydroxymethylbilane synthase (HMBS) mutations that decrease the encoded enzymatic activity, thereby predisposing patients to life-threatening acute neurovisceral attacks. The ~1% penetrance of AIP suggests that other genetic factors modulate the onset and severity of the acute attacks. Here, we characterized the hepatic transcriptomic response to phenobarbital (PB) administration in AIP mice, which mimics the biochemical attacks of AIP. At baseline, the mRNA profiles of 14,138 hepatic genes prior to treatment were remarkably similar between AIP and the congenic wild-type (WT) mice. After PB treatment (~120 mg/kg x 3d), 1347 and 1120 genes in AIP mice and 422 and 404 genes in WT mice were uniquely up- and down-regulated, respectively, at a False Discovery Rate < 0.05. As expected, the ALAS1 expression increased 4.5-fold and 15.9-fold in the WT and AIP mice, respectively. ALA-dehydrogenase also was induced ~1.7-fold in PB-induced AIP mice, but was unchanged in PB-induced WT mice. There was no statistically significant difference in the overall expression of 155 hepatic cytochrome P450 enzymes, although Cyp2c40, Cyp2c68, Cyp2c69, Mgst3 were upregulated only in PB-induced AIP mice (>1.9-fold) and Cyp21a1 was upregulated only in PB-induced WT mice (>9-fold). Notably, the genes differentially expressed in induced AIP mice were enriched in circadian rhythm, mitochondria biogenesis and electron transport, suggesting these pathways were involved in AIP mice responding to PB treatment. These results advance our understanding of the hepatic metabolic changes in PB-induced AIP mice and have implications in the pathogenesis of AIP acute attacks.

Computational disease model of phenobarbital-induced acute attacks in an acute intermittent porphyria mouse model.

INTRODUCTION: Acute intermittent porphyria (AIP) is characterized by hepatic over-production of the heme precursors when aminolevulinic acid (ALA)-synthase 1 is induced by endogenous or environmental factors. The aim of this study was to develop a semi-mechanistic computational model to characterize urine accumulation of heme precursors during acute attacks based on experimental pharmacodynamics data and support the development of new therapeutic strategies. METHODS: Male AIP mice received recurrent phenobarbital challenge starting on days 1, 9, 16 and 30. 24-h urine excretion of ALA, porphobilinogen (PBG) and porphyrins from challenges D1, D9 and D30 constituted the training data set to build the mechanistic model using the population approach. In a second study, porphyrin and porphyrin precursor excretion from challenge D16 were used as a validation data set. RESULTS: The computational model presented the following features: (i) urinary excretion of ALA, PBG and porphyrins was governed by unmeasured circulating heme precursor amounts, (ii) the circulating amounts of ALA and PBG were the precursors of circulating amounts of PBG and porphyrins, respectively, and (iii) the phenobarbital effect linearly increased the synthesis of circulating ALA and PBG levels. The model displayed good parameter precision (coefficient of variation below 32% in all parameters), and adequately described the experimental data. Finally, a theoretical hemin effect was implemented to illustrate the applicability of the model to dosage optimization in drug therapies. CONCLUSIONS: A semi-mechanistic disease model was successfully developed to describe the temporal evolution of urinary heme precursor excretion during recurrent biochemical-induced acute attacks in AIP mice. This model represents the first computational approach to explore and optimize current and new therapies.

Sex differences in vascular reactivity in mesenteric arteries from a mouse model of acute intermittent porphyria.

BACKGROUND AND AIMS: Acute intermittent porphyria (AIP) results from a partial deficiency of porphobilinogen deaminase (PBGD). Symptomatic AIP patients, most of whom are women, experience acute attacks characterized by severe abdominal pain and abrupt increases in blood pressure. Here, we characterized the reactivity of mesenteric arteries from male and female AIP mice with ~30% of normal PBGD activity and wild type C57BL/6 mice. METHODS: An acute porphyric attack was induced in AIP mice by treatment with phenobarbital. Vascular responses to K+, phenylephrine (PE), acetylcholine (ACh), and hemin were determined (Wire Multi Myograph). RESULTS: Maximal contraction to PE was increased in arteries from male and female AIP mice (p < .05) during an induced attack of acute porphyria. Female AIP arteries had increased sensitivity to PE (p < .05) even after nitric oxide (NO) blockade with Nω-nitro-L-arginine methyl ester (L-NAME) (p < .05). Maximal relaxation to ACh was similar in males and females with lower sensitivity in female AIP arteries (p < .05). Hemin induced greater relaxation in AIP arteries in both males and females (p < .05). SUMMARY/CONCLUSIONS: Sex differences in this AIP mouse model include a pro-contractile response in females. These alterations may contribute to the increased blood pressure during an acute attack and provide a novel mechanism of action whereby heme ameliorates the attacks.

[Altered orientation and aggressiveness in an 89-year-old woman]. / Wechselnde Vigilanz und Fremdaggressivität bei einer 89­jährigen Patientin.

An 89-year-old woman with Alzheimer's dementia was admitted because of altered orientation, aggressiveness and inability to take care of herself at home. Her patient history indicated that 14 days ago the battery of the pacemaker had be renewed. During that time the patient suffered from psychomotor alterations. Therefore, melperone had been initiated. Inspection of the urine and laboratory findings pointed towards an acute exacerbation of acute intermittent porphyria as a possible cause of the delirium. After discontinuation of melperone with additional parenteral therapy with physiological fluids, the signs of delirium significantly improved.

[The attack of acute porphyria]. / Genetik och metabola förlopp bakom den akuta porfyriattacken - Mer än hundra läkemedel är potentiellt livshotande vid akut porfyri.

The attack of acute porphyria Based on in silico evidence of pharmacokinetic, pharmacodynamic, and physiologic properties, have approximately 1 300 medicinal drugs been assessed with regard to the specific risk to carriers of acute porphyria. The classifications have been published in booklet form, together with prophylactic advice to the carriers and suggestions for doctors in charge of their care. The risk-classifications rest on the behavior of the drug in an extended molecular model of the attack of acute porphyria. In this, symptoms are effects of 5-aminolevulinate (ALA) produced in surplus after acceleration of enzyme-deficient heme biosynthesis, taking place during induction of drug-metabolizing cytochromes P450 and triggered by hepatocellular nuclear receptors, activated by the drug. The process is enhanced by glucagon- and sirtuin-dependent molecular processes activated in stress and cellular energy deficit, and enhanced and prolonged by auto-generating ALA.

Acute intermittent porphyria precipitated by atazanavir/ritonavir.

Porphyrias are a group of metabolic disorders that are relatively uncommon and underdiagnosed. Although the association between HIV infection and antiretrovirals with porphyria cutanea tarda is well established, there are fewer data linking HIV and the acute hepatic porphyrias. We report the first case of acute intermittent porphyria precipitated by the drugs atazanavir and ritonavir, presenting with unexplained abdominal pain.

Porfiria aguda intermitente en población pediátrica de la región de Murcia: fenotipo y prevalencia / Acute intermittent porphyria in a paediatric population in the region of Murcia: Phenotype and prevalence

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[Mitotane as possible cause of acute intermittent porphyria]. / Mitotan som mulig årsag til akut intermitterende porfyri.

A 54 year-old woman with acute intermittent porphyria (AIP) developed an attack of porphyria after 156 days of treatment with mitotane following a non-radical adrenalectomy for adrenocortical carcinoma. Mitotane therapy was discontinued but the attack of porphyria persisted for more than four months and included episodes with severe metabolic and neurologic toxicities. Mitotane is probably porphyrinogenic for patients with AIP.

How porphyrinogenic drugs modeling acute porphyria impair the hormonal status that regulates glucose metabolism. Their relevance in the onset of this disease.

This work deals with the study of how porphyrinogenic drugs modeling acute porphyrias interfere with the status of carbohydrate-regulating hormones in relation to key glucose enzymes and to porphyria, considering that glucose modulates the development of the disease. Female Wistar rats were treated with 2-allyl-2-isopropylacetamide (AIA) and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) using different doses of AIA (100, 250 and 500mg/kg body weight) and a single dose of DDC (50mg DDC/kg body weight). Rats were sacrificed 16h after AIA/DDC administration. In the group treated with the highest dose of AIA (group H), hepatic 5-aminolevulinic acid synthase (ALA-S) increased more than 300%, phosphoenolpyruvate carboxykinase (PEPCK) and glycogen phosphorylase (GP) activities were 43% and 46% lower than the controls, respectively, plasmatic insulin levels exceeded normal values by 617%, and plasmatic glucocorticoids (GC) decreased 20%. GC results are related to a decrease in corticosterone (CORT) adrenal production (33%) and a significant reduction in its metabolization by UDP-glucuronosyltransferase (UGT) (62%). Adrenocorticotropic hormone (ACTH) stimulated adrenal production 3-fold and drugs did not alter this process. Thus, porphyria-inducing drugs AIA and DDC dramatically altered the status of hormones that regulate carbohydrate metabolism increasing insulin levels and reducing GC production, metabolization and plasmatic levels. In this acute porphyria model, gluconeogenic and glycogenolytic blockages caused by PEPCK and GP depressed activities, respectively, would be mainly a consequence of the negative regulatory action of insulin on these enzymes. GC could also contribute to PEPCK blockage both because they were depressed by the treatment and because they are positive effectors on PEPCK. These disturbances in carbohydrates and their regulation, through ALA-S de-repression, would enhance the porphyria state promoted by the drugs on heme synthesis and destruction. This might be the mechanism underlying the "glucose effect" observed in hepatic porphyrias. The statistical correlation study performed showed association between all the variables studied and reinforce these conclusions.

Drugs in porphyria: From observation to a modern algorithm-based system for the prediction of porphyrogenicity.

The acute porphyrias are a group of disorders which result from inherited defects in the enzymes of the heme biosynthetic pathway. Affected patients are prone to potentially fatal acute attacks. These attacks are frequently precipitated by exposure to commonly used drugs. Correctly identifying the safety or otherwise of drugs in porphyria is therefore important. In this review we describe how clinical experience and the findings of experimental systems using whole animal or cell culture models have been interpreted to determine porphyrogenicity, that is the potential of a drug to induce an acute attack in a patient carrying a gene for acute porphyria. It is now well established that induction of delta-aminolevulinic acid synthase, the rate controlling enzyme of the heme biosynthetic pathway, is fundamental to porphyrogenicity, and that drug-induced hepatic heme depletion via induction or suicidal inactivation of cytochrome P450 is central to this process. The process is now sufficiently well understood that prediction of porphyrogenicity from structural and functional information alone would appear to be justified.

Metabolization of porphyrinogenic agents in brain: involvement of the phase I drug metabolizing system. A comparative study in liver and kidney.

(1) We evaluated the involvement of brain mitochondrial and microsomal cytochrome P-450 in the metabolization of known porphyrinogenic agents, with the aim of improving the knowledge on the mechanism leading to porphyric neuropathy. We also compared the response in brain, liver and kidney. To this end, we determined mitochondrial and microsomal cytochrome P-450 levels and the activity of NADPH cytochrome P-450 reductase. (2) Animals were treated with known porphyrinogenic drugs such as volatile anaesthetics, allylisopropylacetamide, veronal, griseofulvin and ethanol or were starved during 24 h. Cytochrome P-450 levels and NADPH cytochrome P-450 reductase activity were measured in mitochondrial and microsomal fractions from the different tissues. (3) Some of the porphyrinogenic agents studied altered mitochondrial cytochrome P-450 brain but not microsomal cytochrome P-450. Oral griseofulvin induced an increase in mitochondrial cytochrome P-450 levels, while chronic Isoflurane produced a reduction on its levels, without alterations on microsomal cytochrome P-450. Allylisopropylacetamide diminished both mitochondrial and microsomal cytochrome P-450 brain levels; a similar pattern was detected in liver. Mitochondria cytochrome P-450 liver levels were only diminished after chronic Isoflurane administration. In kidney only mitochondrial cytochrome P-450 levels were modified by veronal; while in microsomes, only acute anaesthesia with Enflurane diminished cytochrome P-450 content. (4) Taking into account that delta-aminolevulinic acid would be responsible for porphyric neuropathy, we investigated the effect of acute and chronic delta-aminolevulinic acid administration. Acute delta-aminolevulinic acid administration reduced brain and liver cytochrome P-450 levels in both fractions; chronic delta-aminolevulinic acid administration diminished only liver mitochondrial cytochrome P-450. (5) Brain NADPH cytochrome P-450 reductase activity in animals receiving allylisopropylacetamide, dietary griseofulvin and delta-aminolevulinic acid showed a similar profile as that for total cytochrome P-450 levels. The same response was observed for the hepatic enzyme. (6) Results here reported revealed differential tissue responses against the xenobiotics assayed and give evidence on the participation of extrahepatic tissues in porphyrinogenic drug metabolization. These studies have demonstrated the presence of the integral Phase I drug metabolizing system in the brain, thus, total cytochrome P-450 and associated monooxygenases in brain microsomes and mitochondria would be taken into account when considering the xenobiotic metabolizing capability of this organ.

[Acute intermittent porphyria and oral contraception. Case report]. / Ostra przerywana porfiria i doustna antykoncepcja opis przypadku.

BACKGROUND: Acute intermittent porphyria is the most common type of porphyria occurring in Poland. Its characteristic feature is periods of remissions and aggravations. Aggravation or an attack of the disease is caused by many endogenous and exogenous factors, among others by hormonal contraceptives. CASE REPORT: This article describes the case of an acute intermittent porphyria attack in a 28 years old female patient resulting from the use of a few, contraindicated drugs (metamizole, nospa, desogestrel in case of porphyria, urinary tract infection, as well as a spontaneous abortion two months earlier). The attack included abdominal pain, vomiting, reduction in muscle strength in limbs and it was complicated by seizures caused by hyponatraemia. High excess haem precursors in urine was observed. During hospitalization, the patient ceased to take harmful drugs and she was given haem arginate, glucose and symptomatic drugs, and she recovered completely. CONCLUSION: In the described case there were a few porphyrogenous factors whose action was observed, among which the most important was desogestrel. Due to this conclusion, a change in contraceptive therapy that would exclude hormonal contraception was suggested.

Initial presentation of undiagnosed acute intermittent porphyria as a rare complication of ovulation induction.

OBJECTIVE: To discuss the diagnosis and management of acute intermittent porphyria following ovulation induction. DESIGN: Case report. SETTING: Academic IVF center. PATIENT(S): A patient with polycystic ovary syndrome and primary infertility undergoing ovulation induction with clomiphene citrate. INTERVENTION(S): Serial phlebotomy, IV fluid, inpatient observation. MAIN OUTCOME MEASURE(S): Condition at discharge. RESULT(S): The patient was diagnosed with severe hyponatremia caused by acute volume depletion and possible syndrome of inappropriate antidiuretic hormone secretion, secondary to acute intermittent prophyria, and was successfully managed with supportive measures. Neurovisceral symptoms resolved, and severe hyponatremia was corrected with IV saline solution without complications. CONCLUSION(S): Acute intermittent porphyrias are rare complications of ovulation induction, but should be considered in patients who develop unexplained hyponatremia or neurovisceral symptoms.

Response of glucose metabolism enzymes in an acute porphyria model. Role of reactive oxygen species.

Acute hepatic porphyrias are human metabolic diseases characterized by the accumulation of heme precursors, such as 5-aminolevulinic acid (ALA). The administration of glucose can prevent the symptomatology of these diseases. The aim of this work was to study the relationship between glucose metabolism disturbances and the development of experimental acute hepatic porphyria, as well as the role of reactive oxygen species (ROS) through assays on hepatic key gluconeogenic and glycogenolytic enzymes; phosphoenolpyruvate carboxykinase (PEPCK) and glycogen phosphorylase (GP), respectively. Female Wistar rats were treated with three different doses of the porphyrinogenic drug 2-allyl-2-isopropylacetamide (AIA) and with a single dose of 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Thus, rats were divided into the following groups: group L (100 mg AIA + 50 mg DDC/kg body wt.); group M (250 mg AIA + 50 mg DDC/kg body wt.) and group H (500 mg AIA + 50 mg DDC/kg body wt.). The control group (group C) only received vehicles (saline solution and corn oil). Acute hepatic porphyria markers ALA-synthase (ALA-S) and ferrochelatase, heme precursors ALA and porphobilinogen (PBG), and oxidative stress markers superoxide dismutase (SOD) and catalase (CAT) were also measured in hepatic tissue. On the other hand, hepatic cytosolic protein carbonyl content, lipid peroxidation and urinary chemiluminescence were determined as in vivo oxidative damage markers. All these parameters were studied in relation to the different doses of AIA/DDC. Results showed that enzymes were affected in a drug-dose-dependent way. PEPCK activity decreased about 30% in group H with respect to groups C and L, whereas GP activity decreased 53 and 38% in group H when compared to groups C and L, respectively. On the other hand, cytosolic protein carbonyl content increased three-fold in group H with respect to group C. A marked increase in urinary chemiluminescence and a definite increase in lipid peroxidation were also detected. The activity of liver antioxidant enzyme SOD showed an induction of about 235% in group H when compared to group C, whereas CAT activity diminished due to heme depletion caused by both drugs. Based on these results, we can speculate that the alterations observed in glucose metabolism enzymes could be partly related to the damage caused by ROS on their enzymatic protein structures, suggesting that they could be also linked to the beneficial role of glucose administration in acute hepatic porphyria cases.

Acute intermittent porphyria associated with ovarian stimulation. A case report.

BACKGROUND: Induction of ovulation in the course of infertility treatment is increasingly commonplace in the 21st century. As a consequence, it can be expected that previously unrecognized complications of the procedure will be reported. CASE: A 36-year-old woman presented with severe pelvic pain and hyponatremia after ovarian stimulation with gonadotropins. After admission with a presumptive diagnosis of ovarian hyperstimulation syndrome, a further family history revealed acute intermittent porphyria. A 24-hour urine collection confirmed the diagnosis. CONCLUSION: Hormonal therapy for induction of ovulation in the course of infertility treatment may precipitate attacks of acute intermittent porphyria. A careful history must be undertaken prior to administration of such hormonal preparations.