Odevixibat: A Novel Bile Salt Inhibitor Treatment for Pruritus in Progressive Familial Intrahepatic Cholestasis.

Chronic pruritus is defined as an itch lasting greater than six weeks. It can manifest from a wide variety of etiologies, as many different substances can act as pruritogens, such as steroids, histamine, progesterone, endogenous opioids, and serotonin. In the setting of cholestatic liver disease, increased bile acids play a major role in chronic pruritus. The itching in cholestatic liver disease is worsened in intensity at night and localized frequently to the palms, soles, knees, and other pressure sites. It can be hard to manage, affecting the quality of sleep and causing irritability, poor attention, and, in some cases, depression. One such disease that results from chronic pruritus is progressive familial intrahepatic cholestasis (PFIC), a group of uncommon hereditary disorders that affects the formation of bile and its outflow from the liver. Previously, the drug ursodeoxycholic acid was used to help manage pruritus or surgical procedures, e.g., partial external biliary diversion or partial internal biliary diversion, to help control complications of the disease. This literature review will discuss three clinical studies covering the effectiveness of odevixibat in treating pruritus in patients with PFIC. Odevixibat (Bylvay) is an oral drug that has been FDA-approved to treat pruritus in patients three months of age and older with PFIC. Odevixibat prevents the reabsorption of bile salts in the intestines, resulting in decreased levels of bile salts via their excretion in stool. Several studies have determined that the drug is well tolerated and provides a nonsurgical, pharmacological treatment alternative for those with PFIC.

Progressive Familial Intrahepatic Cholestasis-2 Mimicking Non-accidental Injury.

Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of disorders characterized by defective secretion of bile acids or transport defects resulting in progressive cholestasis. These disorders usually present during infancy or childhood and are associated with progressive liver disease. PFIC is estimated to affect 1 in 50,000-100,000 births, with PFIC-2 representing half of PFIC cases. PFIC-2 presents with hepatosplenomegaly, jaundice, pruritus, fat-soluble vitamin deficiencies, and growth failure. Laboratory findings include low/normal gamma glutamyl transpeptidase levels and elevated bilirubin, transaminases, and alpha-fetoprotein levels. In this report, we present a case of PFIC-2 presenting with severe coagulopathy, bruising, subcutaneous hematomas, and acute-onset anemia.

Emerging drugs for the treatment of progressive familial intrahepatic cholestasis: a focus on phase II and III trials.

INTRODUCTION: Progressive familial intrahepatic cholestasis (PFIC) is a group of disorders characterized by inappropriate bile formation, causing hepatic accumulation of bile acids and, subsequently, liver injury. Until recently, no approved treatments were available for these patients. AREAS COVERED: Recent clinical trials for PFIC treatment have focused on intestine-restricted ileal bile acid transporter (IBAT) inhibitors. These compounds aim to reduce the pool size of bile acids by interrupting their enterohepatic circulation. Other emerging treatments in the pipeline include systemic IBAT inhibitors, synthetic bile acid derivatives, compounds targeting bile acid synthesis via the FXR/FGF axis, and chaperones/potentiators that aim to enhance the residual activity of the mutated transporters. EXPERT OPINION: Substantial progress has been made in drug development for PFIC patients during the last couple of years. Although data concerning long-term efficacy are as yet only scarcely available, new therapies have demonstrated robust efficacy in a considerable fraction of patients at least on the shorter term. However, a substantial fraction of PFIC patients do not respond to these novel therapies and thus still requires surgical treatment, including liver transplantation before adulthood. Hence, there is still an unmet medical need for long-term effective medical, preferably non-surgical, treatment for all PFIC patients.

Normally, the liver produces bile which is a route of secretion of waste products from the body and also helps in the intestinal absorption of fats from the diet. The bile goes from the liver, through the bile duct to the intestines and components are taken up again at the end of the intestine and transported back to the liver. However, progressive familial intrahepatic cholestasis (PFIC in short) is a group of diseases where bile stays in the liver and damages it. PFIC often causes symptoms already in very young children, like itch and jaundice (getting a slight yellow color). Patients get more and worse symptoms over time and may eventually need a liver transplantation. This review discusses what drugs have been developed for PFIC recently and what drugs are in development now. Two new drugs for PFIC have been developed and approved in the last few years: odevixibat and maralixibat. These drugs help bile in the intestines leave the body via the stool and prevent bile from going back to the liver instead. Drugs in development aim to either 1) do the same, 2) make the bile less toxic, 3) reduce the production of bile, or 4) help bile go from the liver into the bile ducts. There has been a lot of progress in drug development for PFIC in the last few years. The new drugs have helped a considerable number of patients, but many patients still do not respond to these new drugs, keep having symptoms and may need surgery. Therefore, despite considerable progress, research needs to continue for an effective treatment for all PFIC patients.

Molecular Insights of Cholestasis in MDR2 Knockout Murine Liver Organoids.

MDR3 (multidrug resistance 3) deficiency in humans (MDR2 in mice) causes progressive familial intrahepatic cholestasis type 3 (PFIC3). PFIC3 is a lethal disease characterized by an early onset of intrahepatic cholestasis progressing to liver cirrhosis, a preneoplastic condition, putting individuals at risk of hepatocellular carcinoma (HCC). Hepatocyte-like organoids from MDR2-deficient mice (MDR2KO) were used in this work to study the molecular alterations caused by the deficiency of this transporter. Proteomic analysis by mass spectrometry allowed characterization of 279 proteins that were differentially expressed in MDR2KO compared with wild-type organoids. Functional enrichment analysis indicated alterations in three main cellular functions: (1) interaction with the extracellular matrix, (2) remodeling intermediary metabolism, and (3) cell proliferation and differentiation. The affected cellular processes were validated by orthogonal molecular biology techniques. Our results point to molecular mechanisms associated with PFIC3 that may drive the progression to liver cirrhosis and HCC and suggest proteins and cellular processes that could be targeted for the development of early detection strategies for these severe liver diseases.

Uncovering the Relationship Between Genes and Phenotypes Beyond the Gut in Microvillus Inclusion Disease.

Microvillus inclusion disease (MVID) is a rare condition that is present from birth and affects the digestive system. People with MVID experience severe diarrhea that is difficult to control, cannot absorb dietary nutrients, and struggle to grow and thrive. In addition, diverse clinical manifestations, some of which are life-threatening, have been reported in cases of MVID. MVID can be caused by variants in the MYO5B, STX3, STXBP2, or UNC45A gene. These genes produce proteins that have been functionally linked to each other in intestinal epithelial cells. MVID associated with STXBP2 variants presents in a subset of patients diagnosed with familial hemophagocytic lymphohistiocytosis type 5. MVID associated with UNC45A variants presents in most patients diagnosed with osteo-oto-hepato-enteric syndrome. Furthermore, variants in MYO5B or STX3 can also cause other diseases that are characterized by phenotypes that can co-occur in subsets of patients diagnosed with MVID. Recent studies involving clinical data and experiments with cells and animals revealed connections between specific phenotypes occurring outside of the digestive system and the type of gene variants that cause MVID. Here, we have reviewed these patterns and correlations, which are expected to be valuable for healthcare professionals in managing the disease and providing personalized care for patients and their families.

Clinical outcomes of ABCB4 heterozygosity in infants and children with cholestatic liver disease.

OBJECTIVES: Biallelic variants in the adenosine triphosphate binding cassette subfamily B member 4 (ABCB4) gene which encodes the multidrug resistance 3 protein (MDR3) leads to progressive familiar intrahepatic cholestasis type 3. However, monoallelic variants are increasingly recognized as contributing to liver disease in adults. Our aim was to describe the clinical characteristics of MDR3 heterozygous variants in a large cohort of infants and children with cholestatic liver disease. METHODS: The clinical and genotypic data on pediatric patients seen at King's College Hospital, London, between 2004 and 2022 and found to harbour heterozygous variants in ABCB4 were reviewed. RESULTS: Ninety-two patients amongst 1568 tested were identified with a monoallelic variant (5.9%). The most common presenting problem was conjugated hyperbilirubinemia (n = 46; 50%) followed by cholelithiasis (n = 12; 13%) and cholestatic hepatitis (n = 10; 11%). The median values of liver biochemistry at presentation were: GGT 105 IU/L and total bilirubin 86 µmol/L. Thirty-two genetic variants were identified including 22 missense (69%), 4 deletions (13%), 5 splice site (16%) and 1 termination (3%). At a median follow up of 1 year there was resolution of liver disease. CONCLUSIONS: Rare variants in ABCB4 were found amongst infants and children with cholestatic liver disease. The presenting problems were variable and abnormalities tended to normalize over time. Those with severe mutations could develop liver disease later in life when exposed to further insult and should be counseled appropriately.

Comprehensive Bile Acid Profiling of ABCB4-mutated Patients and the Prognostic Role of Taurine-conjugated 3α,6α,7α,12α-Tetrahydroxylated Bile Acid in Cholestasis.

Background and Aims: We asked if comprehensive bile acid profiling could provide insights into the physiopathology of ABCB4-mutated patients and evaluated the prognostic value of taurine-conjugated tetrahydroxylated bile acid (tauro-THBA) in cholestasis. Methods: Serum bile acid profiles were evaluated in 13 ABCB4-mutated patients with 65 healthy controls by ultra-high-performance liquid chromatography/multiple-reaction monitoring-mass spectrometry (UPLC/MRM-MS). The concentration of tauro-THBA was compared between ABCB4-mutated patients with different prognoses. The areas under the curve (AUCs) of tauro-THBA were compared between ABCB11-mutated patients with native liver survival and those who died or underwent liver transplantation before 3 years of age by receiver operating characteristic curve (ROC), with another patient cohort for further verification. Results: The overall hydrophobicity indices of bile acids in ABCB4-mutated patients (12.99±3.25 m) were significantly lower than those of healthy controls (14.02±1.74 m, p<0.000). That was due to markedly increased bile acid modifications including conjugation, sulfation, and ketonization. Differences in the tauro-THBA concentration in ABCB4-mutated patients with different prognoses were not significant. ROC analysis indicated that levels of tauro-THBA of <60 nM yielded an AUC of 0.900 with a sensitivity of 80% and specificity of 87.5% for ABCB11-mutated patients with different prognoses (p=0.0192). Of the 15 patients with good prognosis, 14 were classified correctly and four of the five patients with a poor prognosis were classified correctly (14:15 vs. 1:5, p=0.005) with tauro-THBA as a classifier. Conclusions: Tauro-THBA concentration may be a biomarker for predicting the clinical outcome in low gamma-glutamyl transferase intrahepatic cholestasis patients.

NR1H4 mutation and rapid progressive intrahepatic cholestasis in infancy: A case report and literature review.

Farnesoid X receptor (FXR) is a nuclear bile acid receptor encoded by the NR1H4 gene, a vital regulator of bile acid homeostasis. Pathogenic mutations of NR1H4 manifest as low gamma-glutamyl transferase (GGT) cholestasis with rapid progression to liver failure, which is referred to as progressive familial intrahepatic cholestasis 5 (PFIC-5). Herein, we present a case with rapid progressive cholestasis, liver failure in early infancy with the NR1H4 termination mutation.

Opinion paper on the diagnosis and treatment of progressive familial intrahepatic cholestasis.

Background & Aims: Progressive familial intrahepatic cholestasis (PFIC) relates to a group of rare, debilitating, liver disorders which typically present in early childhood, but have also been reported in adults. Without early detection and effective treatment, PFIC can result in end-stage liver disease. The aim of the paper was to put forward recommendations that promote standardisation of the management of PFIC in clinical practice. Methods: A committee of six specialists came together to discuss the challenges faced by physicians in the management of PFIC. The committee agreed on two key areas where expert guidance is required to optimise care: (1) how to diagnose and treat patients with a clinical presentation of PFIC in the absence of clear genetic test results/whilst awaiting results, and (2) how to monitor disease progression and response to treatment. A systematic literature review was undertaken to contextualise and inform the recommendations. Results: An algorithm was developed for the diagnosis and treatment of children with suspected PFIC. The algorithm recommends the use of licensed inhibitors of ileal bile acid transporters as the first-line treatment for patients with PFIC and suggests that genetic testing be used to confirm genotype whilst treatment is initiated in patients in whom PFIC is suspected. The authors recommend referring patients to an experienced centre, and ensuring that monitoring includes measurements of pruritus, serum bile acid levels, growth, and quality of life following diagnosis and during treatment. Conclusions: The algorithm presented within this paper offers guidance to optimise the management of paediatric PFIC. The authors hope that these recommendations will help to standardise the management of PFIC in the absence of clear clinical guidelines. Impact and implications: This opinion paper outlines a consistent approach to the contemporaneous diagnosis, monitoring, referral and management of children with progressive familial intrahepatic cholestasis. This should assist physicians given the recent developments in genetic diagnosis and the availability of effective drug therapy. This manuscript will also help to raise awareness of current developments and educate health planners on the place for new drug therapies in progressive familial intrahepatic cholestasis.

Successful Use of Bortezomib for Recurrent Progressive Familial Intrahepatic Cholestasis Type II After Liver Transplantation: A Pediatric Case with a 9-Year Follow-Up.

Recurrence of progressive familial intrahepatic cholestasis (PFIC) type II poses challenges during postoperative liver transplant care. Posttransplant patients with PFIC type II risk developing recurrent cholestasis with normal gamma-glutamyl transferase activity, which mimics the original bile salt export pump (BSEP) protein deficiency and is related to a form of immunoglobulin G antibody (anti-BSEP)-mediated rejection. Bortezomib effectively induces apoptosis of actively antibody-producing plasma cells that may have a role in antibody-mediated rejection. In this case, we used bortezomib to treat PFIC type II recurrence after liver transplantation in a child.

Expression of miR-let7b and miR-19b in progressive familial intrahepatic cholestasis (PFIC) children.

BACKGROUND: MicroRNAs (miRNAs) are a group of small non-coding RNAs that bind to the target mRNA and regulate gene expression. Recently circulating microRNAs were investigated as markers of diseases and therapeutic targets. Although various studies analyze the miRNA expression in liver disease, these studies on PFIC are few. Progressive familial intrahepatic cholestasis (PFIC) is a rare liver disease with autosomal recessive inheritance. Most children with PFIC progress to cirrhosis and liver failure and consequently need to have a liver transplant. The aim of this study is the investigation of the miR-19b and miR-let7b expression levels in Iranian PFIC children. METHODS: 25 PFIC patients, 25 healthy children and 25 Biliary Atresia patients were considered as case and two control groups respectively. Blood samples were obtained and Liver function tests (LFTs) were measured. After RNA extraction and cDNA synthesis, quantitative PCR was performed using specific primers for miR-19b and miR-let7b. The U6 gene is used as an internal control. RESULTS: qPCR on PFIC patients' samples demonstrated that the miR-19b and the miR-let7b expression were significantly decreased in patients compared to the control groups, with a p-value<0.0001 and p-value=0.0006 receptively. CONCLUSION: In conclusion, circulating micro-RNA like miR-19b and miR-let7b have a potential opportunity to be a non-invasive diagnostic marker or therapeutic target for PFIC in the future.

Molecular and computational characterization of ABCB11 and ABCG5 variants in Tunisian patients with neonatal/infantile low-GGT intrahepatic cholestasis: Genetic diagnosis and genotype-phenotype correlation assessment.

Many inherited conditions cause hepatocellular cholestasis in infancy, including progressive familial intrahepatic cholestasis (PFIC), a heterogeneous group of diseases with highly overlapping symptoms. In our study, six unrelated Tunisian infants with PFIC suspicion were the subject of a panel-target sequencing followed by an exhaustive bioinformatic and modeling investigations. Results revealed five disease-causative variants including known ones: (the p.Asp482Gly and p.Tyr354 * in the ABCB11 gene and the p.Arg446 * in the ABCC2 gene), a novel p.Ala98Cys variant in the ATP-binding cassette subfamily G member 5 (ABCG5) gene and a first homozygous description of the p.Gln312His in the ABCB11 gene. The p.Gln312His disrupts the interaction pattern of the bile salt export pump as well as the flexibility of the second intracellular loop domain harboring this residue. As for the p.Ala98Cys, it modulates both the interactions within the first nucleotide-binding domain of the bile transporter and its accessibility. Two additional potentially modifier variants in cholestasis-associated genes were retained based on their pathogenicity (p.Gly758Val in the ABCC2 gene) and functionality (p.Asp19His in the ABCG8 gene). Molecular findings allowed a PFIC2 diagnosis in five patients and an unexpected diagnosis of sisterolemia in one case. The absence of genotype/phenotype correlation suggests the implication of environmental and epigenetic factors as well as modifier variants involved directly or indirectly in the bile composition, which could explain the cholestasis phenotypic variability.

Differentiating biliary atresia from other causes of infantile cholestasis: An appraisal of the histomorphological changes on liver biopsy.

Background: Cholestatic disorders are a significant cause of morbidity and mortality in infants. Characterization of these disorders and differentiating biliary atresia (BA) from other causes of intrahepatic cholestasis is an age-old problem. Objectives: To study the spectrum of different infantile cholestatic disorders in our population, to differentiate BA from other causes of neonatal cholestasis (NC) on a liver biopsy, and validation of the available scoring system for the characterization of these disorders. Materials and Methods: This is an observational cross-sectional study performed over a period of 3 years between 2018 and 2021, done on neonates and infants presenting with cholestatic jaundice. The changes on liver biopsy were evaluated by different histological parameters and available scoring systems to differentiate BA from non-BA causes. Correlation with clinical, biochemical, and imaging findings was done in all cases. Results: This study included 87 cases of NC, of which BA comprised 28 cases (32%), whereas idiopathic neonatal hepatitis (INH) comprised only 12 cases (14%). Portal neutrophilic inflammation (P = 0.000053), ductal cholestasis (P < 0.001), neoductular bile plugs (P < 0.001) and bile ductular proliferation (P < 0.0001) were significantly more in BA, whereas lobular lymphocytic inflammation (P = 0.001) and giant cell transformation of hepatocytes (P = 0.0024) were more frequent in the non-BA group. Using the Lee and Looi scoring system, a histologic score ≥7 was helpful in identifying BA with 85.7% sensitivity, 92.6% specificity, and 90.6% accuracy. Conclusion: BA is the commonest cause of NC in neonates, whereas the frequency of INH is declining. Detailed histomorphologic analysis of liver biopsy, aided with IHC, is the cornerstone for the diagnosis of these disorders.

A Rare Case of Progressive Familial Intrahepatic Cholestasis Type 4: A Case Report and Literature Review.

Progressive familial intrahepatic cholestasis (PFIC) is a group of genetic disorders characterized by progressive intrahepatic cholestasis. Different mutations in hepatocellular transport genes result in distinct PFIC subtypes with unique clinical manifestations, laboratory findings, and histopathological characteristics. Three PFIC genotypes have been commonly described (PFIC 1, 2, and 3), but in recent years, PFIC 4, 5, and 6 genetic mutations have been identified. Here, we report the first PFIC 4 case in the Middle East in a 46-day-old male infant who was successfully treated with a liver transplant. A 46-day-old, male, full-term infant presented with persistent jaundice and obstructive liver pathology suggested by liver profile and biopsy. Whole exome sequencing confirmed the diagnosis of PFIC 4. Medical treatment failed to improve the patient's symptoms. Therefore, the patient underwent hepatectomy and an unrelated liver transplant. He is currently exhibiting significant clinical improvements and is free of active complaints. PFIC is a rare disease that poses diagnostic and therapeutic challenges for clinicians. Infants presenting with unexplained cholestasis should have PFIC 4 as a differential diagnosis. Early recognition and treatment of PFIC 4 with liver transplantation may result in a more favorable prognosis.

Evaluation of Clinical Outcomes in Children with Intrahepatic Cholestasis Postpartial External Biliary Diversion: A Single-Center Experience.

Background: Severe pruritus caused by progressive familial intrahepatic cholestasis (PFIC) and Alagille syndrome (AGS) is refractory to medical treatment. Surgical interruption of the enterohepatic circulation is considered the mainstay of alleviating distressing symptoms and delaying cirrhosis. Aim and Objectives: This study aims to evaluate the short-term effect of partial external biliary diversion (PEBD) on pruritus, liver disease progression, patient's growth, and quality of life. Material and Methods: This prospective cohort study enrolled children with PFIC and AGS from July 2019 to July 2021, whose guardians consented to the PEBD procedure. A standard surgical approach was performed by a single surgeon. Outcomes were measured subjectively and objectively pre- and post-procedure using the pruritus 5-D itching score, Paediatric Quality of Life Inventory scale (PedsQL), growth parameters, bile acids level, and liver function tests. Patients' follow-up period ranged from 6 to 12 months. Results: Seven patients had PEBD procedure; five with PFIC and two with AGS. A significant improvement was detected in the 5-D itching score (p-value < 0.001), PedsQL (p-value < 0.001), and bile acids level (p-value 0.013). The preexisting growth failure was ameliorated. The downward trend in the bilirubin level was not significant. No influential difference in the other liver function tests occurred. No intra-operative complications encountered. Only one case had a post-operative stoma prolapse which was managed surgically. Conclusion: PEBD procedure could be considered as an effective and safe treatment options for intractable pruritus in patients with PFIC or AGS, providing preserved synthetic liver functions.

A female of progressive familial intrahepatic cholestasis type 3 caused by heterozygous mutations of ABCB4 gene and her cirrhosis improved after treatment of ursodeoxycholic acid: a case report.

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a group of rapidly progressive autosomal recessive disorders characterized by intrahepatic cholestasis. PFIC-3 is caused by mutations in the ATP-binding cassette subfamily B member 4 gene (ABCB4), which encodes multidrug resistance protein 3 (MDR3/ABCB4). Patients are usually in infancy or childhood, but cirrhosis and portal hypertension may be the first manifestation in older children or young adults. CASE PRESENTATION: A 25-year-old young woman with recurrent abnormal hepatic function was mainly characterized by increased gamma glutamyl transpeptidase (GGT) and bile acid with cryptogenic cirrhosis. After 7 months of treatment with ursodeoxycholic acid (UDCA), her hepatic pathology suggested there were also obvious widening and venous fibrosis around the portal vein, and slight bile duct hyperplasia at the edge of the portal area. Infiltration of inflammatory cells around the portal vein and hepatocyte ABCB4/MDR3 protein was basically normal. Sequencing indicated the patient had heterozygous mutations in the ABCB4 gene: c.2696C > G and wes [hg19]7q21.12(87032513-87033422) × 1. Through SWISS-MODEL Predict for protein structures, the missense mutation results in protein side chain missing a methyl group (-CH3), and the deletion mutation results in the serious damage to the structure of MDR3 protein which lead to phosphatidylcholine deficiency of bile in the capillary bile ducts. The toxic effect of bile salts then damages the bile ducts, causing cholestasis and cholangitis, which can then develop into biliary cirrhosis. Through the analysis of pathogenicity prediction software, the mutations led to PFIC3. After treatment of UDCA for 29 months, her cirrhosis was improved, hepatic function was close to normal. CONCLUSION: Novel heterozygous mutations are the molecular pathological cause of PFIC3 in this patient. All young adult patients with occult cirrhosis should be tested for ABCB4. Early diagnosis of PFIC3 and continued treatment with UDCA are key to improving prognosis and delaying the onset of end-stage liver disease.

Treatment with an ileal bile acid transporter inhibitor in patients with TJP2 deficiency.

There are no published data on the use of odevixibat, a selective ileal bile acid transporter (IBAT) inhibitor, in children with tight junction protein 2 (TJP2) deficiency (also named as PFIC-4). We describe a case series of five children treated with odevixibat. After treatment, serum bile acids (sBA) decreased compared to baseline [mean value: 244 (±125), vs 38 (±34) µmol/L; p = 0.007]; reduction in sBA was >70% from baseline (or <70 µmol/L) in all. Improvements in pruritus were reported in all patients. The drug was well tolerated. IBAT inhibitors should be considered a valuable treatment option in patients with TJP2 deficiency.

Progressive familial intrahepatic cholestasis-outcome and time to transplant after biliary diversion according to genetic subtypes.

Background: Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous disease characterized by progressive cholestasis in early childhood. Surgical therapy aims at preventing bile absorption either by external or internal biliary diversion (BD). Several different genetic subtypes encode for defects in bile transport proteins, and new subtypes are being discovered ongoingly. Overall, the literature is scarce, however, accumulating evidence points to PFIC 2 having a more aggressive course and to respond less favorable to BD. With this knowledge, we aimed to retrospectively analyze the long-term outcome of PFIC 2 compared to PFIC 1 following BD in children at our center. Methods: Clinical data and laboratory findings of all children with PFIC, who were treated and managed in our hospital between 1993 and 2022, were analyzed retrospectively. Results: Overall, we treated 40 children with PFIC 1 (n = 10), PFIC 2 (n = 20) and PFIC 3 (n = 10). Biliary diversion was performed in 13 children (PFIC 1, n = 6 and 2, n = 7). Following BD, bile acids (BA) (p = 0.0002), cholesterol (p < 0.0001) and triglyceride (p < 0.0001) levels significantly decreased only in children with PFIC 1 but not in PFIC 2. Three out of 6 children (50%) with PFIC 1 and 4 out of 7 children (57%) with PFIC 2 required liver transplantation despite undergoing BD. On an individual case basis, BA reduction following BD predicted this outcome. Of the 10 children who had PFIC 3, none had biliary diversion and 7 (70%) required liver transplantation. Conclusion: In our cohort, biliary diversion was effective in decreasing bile acids, cholesterol levels as well as triglycerides in the serum only in children with PFIC 1 but not PFIC 2. On an individual case level, a decrease in BA following BD predicted the need for liver transplantation.

Iterative antibody-induced bile salt export pump deficiency after successive liver transplantations successfully treated with plasmapheresis and rituximab.

Post-transplantation evolution of progressive familial intrahepatic cholestasis type 2 patients can be complicated by antibody-induced bile salt export pump deficiency (AIBD). There is no consensus on its management. We describe a patient who presented two episodes, 9 years apart. The first episode was refractory to plasmapheresis and intravenous immunoglobulin (IVIG) started 2 months after AIBD onset, leading to graft loss. The second episode responded to plasmapheresis, IVIG and rituximab initiated less than 2 weeks after the beginning of symptoms, allowing for long-term recovery. This case suggests that intensive treatment with minimum delay after symptoms onset could sponsor a better evolution.

Case Report: Add-on treatment with odevixibat in a new subtype of progressive familial intrahepatic cholestasis broadens the therapeutic horizon of genetic cholestasis.

Odevixibat, an ileal bile acid transporter (IBAT) inhibitor, is effective for the treatment of pruritus in children diagnosed with progressive familial intrahepatic cholestasis (PFIC) type 1 and 2. There are no studies showing the efficacy of Odevixibat in children with different subtypes of PFIC. We describe the case of a 6-year-old girl with chronic cholestatic jaundice. In the last 12 months laboratory data showed high serum levels of bilirubin (total bilirubin x 2.5 ULN; direct bilirubin x 1.7 ULN) and bile acids (sBA x 70 ULN), elevated transaminases (x 3-4 ULN), and preserved synthetic liver function. Genetic testing showed homozygous mutation in ZFYVE19 gene, which is not included among the classic causative genes of PFIC and determined a new non-syndromic phenotype recently classified as PFIC9 (OMIM # 619849). Due to the persistent intensity of itching [score of 5 (very severe) at the Caregiver Global Impression of Severity (CaGIS)] and sleep disturbances not responsive to rifampicin and ursodeoxycholic acid (UDCA), Odevixibat treatment was started. After treatment with odevixibat we observed: (i) reduction in sBA from 458 to 71 µmol/L (absolute change from baseline: -387 µmol/L), (ii) reduction in CaGIS from 5 to 1, and (iii) resolution of sleep disturbances. The BMI z-score progressively increased from -0.98 to +0.56 after 3 months of treatment. No adverse drug events were recorded. Treatment with IBAT inhibitor was effective and safe in our patient suggesting that Odevixibat may be potentially considered for the treatment of cholestatic pruritus also in children with rare subtypes of PFIC. Further studies on a larger scale could lead to the increasing of patients eligible for this treatment.