Category Archives: Pediatric Gastroenterology Liver Disease

Phase 3 Trial of Sebelipase Alfa for Lysosomal Acid Lipase Deficiency

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A recent report (BK Burton et al. NEJM 2015; 373: 1010-20, editorial 1071-1) provides preliminary evidence of efficacy of Sebeliplase Alfa for lysosomal acid lipase deficiency.

In this multicenter, randomized, double-blind, placebo-controlled study of 66 patients, enzyme replacement therapy with Sebelipase alfa was examined (1 mg intravenously every other week).  After 20 weeks, all patients were treated by open-label. Of the 32 patients who had had liver biopsies, 10 (31%) were noted to have cirrhosis.

Findings:

  • Alanine aminotransferase normalized in 11 (36%) of treated patients compared with 2 (7%) of controls
  • Improvement in lipid levels and reduction in hepatic fat content were evident in treated patients (P<0.001 for all comparisons, except P-0.04 for triglycerides

The editorial provides a schematic explaining how sebelipase alfa targets the hepatocyte (Figure 1).  The authors note that “longer-term follow-up in a larger number of patients will be required for confirmation.”

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Antivirals Reduce Vertical Transmission of Hepatitis B

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Chelsea Market, NYC

Chelsea Market, NYC

The latest study that shows antivirals interrupt hepatitis B viral (HBV) transmission from mother-to-infant: H-L Chen et al. Hepatology 2015; 62: 375-86.

In this open-label, non-randomized controlled study from Taiwan, the researchers recruited women to receive tenofovir (TDF) at a dose of 300 mg once a day (n=62), initiated from gestational age 30-32 weeks until 1 month following delivery, and compared them to a control group (n=56).  There were high levels of viremia with HBV DNA ≥7.5 log10 IU/mL. All infants received HBV vaccination and HBIG within 24 hours of birth.

Key findings:

  • Infant transmission of HBV was reduced: at 6 months of age, infant HBsAg positivity was 1.54% versus 10.71%, P=0.0481).  At delivery, HBV DNA positivity was noted in 6.15% compared with 31.48% of the control group.
  • Maternal ALT was improved in the TDF group. ALT elevation more than two times the upper limit of normal for ≥3 months occurred in 3.23% compared with 14.29% of controls.
  • Adverse effects: only mild to moderate (self-limited) gastrointestinal and skin symptoms were noted. No fetal abnormalities were identified.

Bottomline: Antivirals, including both tenofovir and telbivudine, reduce vertical HBV transmission with a favorable safety profile.  The use of antivirals is complementary to standard prevention which consists of providing Hepatitis B immune globulin and Hepatitis B vaccine to infants of HBV-infected pregnant women within 12 hours of birth.

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Pediatric Entecavir Data

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While entecavir and tenofovir have been in use for many years in adult hepatology for hepatitis B virus (HBV) infection, a well-designed study supporting their use in pediatrics has been lacking until now.  Recently, a study (M Jonas et al. Hepatology 2015; DOI: 10.1002/hep.28015)  has shown that entecavir is effective for pediatric HBV

Link to full study. Randomized Controlled Trial of Entecavir Versus Placebo in Children with HBeAg-positive Chronic Hepatitis B

Here’s the abstract:

This ongoing, randomized phase III study assesses the safety and efficacy of entecavir versus placebo in nucleos(t)ide-naive children (2 to <18 years) with HBeAg-positive chronic hepatitis B (CHB). Blinded treatment was administered for a minimum of 48 weeks. After Week 48, patients with HBeAg seroconversion continued blinded treatment; those without, switched to open-label entecavir. The primary endpoint was HBeAg seroconversion and HBV DNA <50 IU/mL at Week 48. A total of 180 patients were randomized (2:1) and treated. Baseline median age was 12 years, with approximately 50% of children aged >12 to <18, and 25% each aged ≥2 to ≤6 and >6 to ≤12. Rates for the primary endpoint at Week 48 were significantly higher with entecavir than placebo (24.2% [29/120] versus 3.3% [2/60]; P=0.0008). Furthermore, higher response rates were observed with entecavir compared with placebo for the key Week 48 secondary endpoints: HBV DNA <50 IU/mL (49.2% [59/120] versus 3.3% [2/60]; P < 0.0001), alanine aminotransferase normalization (67.5% [81/120] versus 23.3% [14/60]; P < 0.0001), and HBeAg seroconversion (24.2% [29/120] versus 10.0% [6/60]; P = 0.0210). Among entecavir-randomized patients there was an increase in all efficacy endpoints between Weeks 48 and 96, including an increase from 49% to 64% in virologic suppression. The cumulative probability of emergent entecavir resistance through Years 1 and 2 of entecavir was 0.6 and 2.6%, respectively. Entecavir was well tolerated with no observed differences in adverse events or changes in growth compared with placebo. Conclusion: In childhood CHB, entecavir demonstrated superior antiviral efficacy to placebo with a favorable safety profile. These results support the use of entecavir as a therapeutic option in children and adolescents with CHB.

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From Brooklyn Bridge

From Brooklyn Bridge

 

Helpful Review on Biliary Atresia

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Biliary atresia (BA) remains the leading cause of pediatric liver transplantation and a frequent cause of cholestasis in newborns.  A recent review (AG Feldman, CL Mack. JPGN 2015; 61: 167-75) provides a helpful update. The article begins with a review on pathogenesis, though this remains unknown and continues to be an area of speculation.

The section on evaluation includes a suggested diagnostic algorithm for neonatal cholestasis.  In short, for a 2 week old with jaundice , the authors recommend (STEP 1) fractionating the bilirubin.  The infant is considered cholestasis if the direct bilirubin is ≥1 mg/dL (if total bilirubin is <5 mg/dL) or if direct bilirubin ≥20% of total bilirubin (if total bilirubin is >5 mg/dL).

Among cholestatic infants, the authors recommend (STEP 2) next checking ultrasound and alpha-one antitrypsin (A1AT) (level & phenotype).  The text implies that the authors would check a GGTP.  While this is not in their algorithm, many would suggest checking urine reducing substances, coags, serum glucose, and consideration of sepsis evaluation; these tests can identify issues that are more urgent than identifying biliary atresia.

STEP 3: If U/S and A1AT, are not diagnostic, consider urine culture, urine reducing substances, urine succinylacetone, and additional infectious studies.

STEP 4: Proceed with liver biopsy. If findings of biliary atresia (eg. bile plugs, bile duct proliferation, portal fibrosis), proceed with intraoperative cholangiogram.

Other points:

  • “It is rare for an infant with BA to have a GGTP level <200 U/L.” If low GGTP, consider PFIC, inborn error of bile acid metabolism, and panhypopituitarism.
  • Extensive differential diagnosis table given ((Table 1)
  • “Late diagnosis of BA remains a problem in the United States. The average age of HPE [hepatoportoenterostomy] is 61 days and 44% of patients still undergo HPE after 60 days of life.”  The authors indicate a goal for HPE of taking place  at <45 days of life.
  • Successful HPE can occur even with late diagnosis. 10% to 20% of children who undergo HPE after 100 to 120 days of life still have success in restoring bile flow.”
  • Early/successful HPE is helpful in increasing 10-year transplant-free rate.  Early on, 3 months after HPE, those with a total bilirubin <2 mg/dL compared with those with a total bilirubin of >6 mg/dL have a much lower likelihood of liver transplantation by 2 years of age: 84% vs. 16%.
  • Recommends checking a pulse oximetry at routine followup visits following HPE to look for the possibility of hepatopulmonary syndrome.
  • The article reviews complications including ascites, portal hypertension/GI bleeding, cholangitis, malignancy, and hepatopulmonary syndrome/portopulmonary hypertension.
  • Outcomes: With HPE, “up to two-thirds of patients with BA have short-term clearance of jaundice.” Yet, “80% of patients with biliary atresia will require liver transplantation during childhood.”

Also noted:

“Biliary Atresia is Associated with Hypertension” JPGN 2015; 61: 182-86.

“Pathogenesis of biliary atresia: defining biology to understand clinical phenotypes” A Asai, A Miethke, JA Bezerra. Nat Rev Gastroenterol Hepatol 2015; 12: 343-52.  This review provides in-depth review examines more precise phenotyping, influencing factors (eg. cytomegalovirus), and potential mechanisms.

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From Mt Washburn, Yellowstone

From Mt Washburn, Yellowstone

Impact of Kasai Portoenterostomy on Liver Transplantation

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Briefly noted: JS Neto, et al. Liver Transpl 2015; 21: 922-7.

This retrospective cohort study of 347 biliary atresia patients who underwent liver transplantation )LT) (1995-2013) divided patients into eraly Kasai failures (K-EF) (27%), late Kasai failures (K-LF) (33%), and no Kasai portenterostomy (No-K) (40%). K-EF was defined by patients who underwent LT before 12 months of age.

Key findings:

  • After adjustment of confounding factors, the K-LF group had an 84% less probability of dying and 55% less chance to undergo retransplantation.
  • Having a K-EF did not have an effect on patient or graft survival compared to No-K.
  • Both the K-LF and K-EF had more post-LT biliary complications.

Bottomline: This retrospective study suggests that if a Kasai portoenterostomy helps postpone LT then this results in improved outcomes; whereas if it is ineffective, it does not impact survival compared to those who did not undergo a Kasai.

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From Cascade Canyon, Grand Tetons

From Cascade Canyon, Grand Tetons

What HBV Testing is Needed Before Tumor Necrosis Factor Inhibitor Therapy

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As noted in a previous blog post (What’s Going on with Hepatitis A and Hepatitis B?):

Hepatitis B Reactivation risk & recommendation: (For all of the specifics — Full text article link)

  • High risk of reactivation (>10%): B cell depleting agents (eg. rituximab, ofatumumab), anthracycline derivatives (eg. doxorubicin, epirubicin), and daily moderate to high dose steroids (>10 mg) for at least 4 weeks. Recommendation: Use HBV prophylaxis
  • Moderate risk of reactivation (1-10%): anti-TNF therapy, integrin inhibitors (eg. ustekinimab, vedolizumab), tyrosine kinase inhibitors, low-dose steroids daily (<10 mg/day) for at least 4 weeks.  Recommendation: Use HBV prophylaxis if HBsAg-positive but not if only anti-HBc-positive
  • Low risk of reactivation (<1%): azathiopurine, 6-mercaptopurine, methotrexate. Recommendation: No antiviral prophylaxis required.

For those interested in a more detailed summary of the recommendations: AGA Website HBV Reactivation Recommendations

In line with the reactivation risk, a new study (and editorial) (M Barone et al. Hepatology 2015; 62: 40-6; editorial BP Perillo. Hepatology 2105; 62: 16-8) indicates that for those receiving tumor necrosis inhibitor (anti-TNF) monotherapy, hepatitis B screening requires only checking HBsAg. The study examined a total of 1218 Caucasian rheumatologic patients (receiving biologic agents) between 2001-12. In this cohort, the authors identified 179 patients who had a previously resolved HBV infection; 146 treated with anti-TNF, 14 with rituximab, and 19 with other biologic therapy. Key finding: HBV reactivation was not seen in these patients.

Bottomline: For most pediatric patients receiving anti-TNF monotherapy (eg. infliximab, adalimumab), screening with HBsAg alone should suffice.

Disclaimer: These blog posts are for educational purposes only. Specific dosing of medications/diets (along with potential adverse effects) should be confirmed by prescribing physician/nutritionist.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Grand Tetons from Jackson Lodge

Grand Tetons from Jackson Lodge

“What Causes Biliary Atresia?”

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Deceptive Tweet or Great ‘Hook?’

Deceptive Tweet or Great 'Hook?'

The title was tweeted by the AGA and definitely piqued my interest.  The link that was provided connects to a full-text article (Mack C, CMGH 2015; 1: 267-74) on the potential immunopathogeneis of biliary atresia in the neonatal period.  While the article provides a lot of information, it really does not come close to answering the title question.  In my view, this article reminds me of many other articles on other enigmatic liver diseases in which the clues on pathogenesis led in the wrong direction (eg. antioxidants for gestational alloimmune liver disease)

Here’s from the abstract and the summary:

From abstract:

The neonatal presentation of BA prompts the question of what potential modifications of unique aspects of the neonatal immune system set the stage for the progressive biliary disease. This review also discusses the characteristics of neonatal immune response and the theories on how alterations of this response could contribute to the pathogenesis of BA. These include aberrant type 1 helper T-cell (TH1) and TH17 responses, deficiencies in regulatory T cells, activation of humoral immunity, and autoimmunity. To advance our understanding of the etiology of BA, future studies should focus on the unique aspects of the neonatal immune system that have gone awry.

From summary:

Biliary atresia is a devastating disease wherein the vast majority of patients require liver transplantation for survival. It is critical to grasp the immunopathogenesis of BA in order to provide future therapies that control the intrahepatic biliary inflammation and prevent subsequent fibrosis. Evidence exists for a key role of both arms of the adaptive immune response in bile duct injury. The neonatal presentation of BA provides a clue to disease pathogenesis. Early events that impact the neonatal immune system (ie, perinatal virus infection) may alter the immune response and promote a progressive inflammatory or biliary autoimmune disease. To advance our understanding of the etiology of BA, future studies should focus on those unique aspects of the neonatal immune system that have gone awry, as detailed throughout this review.

Bottomline: Clues are important but do not answer the question of what causes biliary atresia.

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Preventing Vertical Transmission of Hepatitis B with Telbivudine

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Briefly noted:

Wu Q et al. Clin Gastroenterol Hepatol 2015; 13: 1170-76.  This was a prospective study of 450 Hepatitis B e antigen-positive pregnant women with HBV DNA levels greater than 10 to the 6th IU/mL.  279 women received telbivudine 600 mg daily starting between 24 to 32 weeks of gestation until delivery or up to a month thereafter; this treatment group was compared to 171 controls women unwilling to take the medication. All infants received vaccinations after birth along with hepatitis B immune globulin. None of the infants in the treatment arm acquired hepatitis B (negative HBsAg at 6 months) compared with 14.7% of infants in the control arm who were positive for infection.  no serious adverse effects were noted in the women receiving telbivudine or their infants.

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When Will MRI Obviate the Need for a Liver Biopsy in Pediatric NAFLD?

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A recent study (JB Schwimmer et al. Hepatology 2015; 1887-95, editorial Vos MB, pages 1779-80) examines the accuracy of magnetic resonance imaging (MRI) compared with liver histology in children with nonalcoholic fatty liver disease.

This prospective validation study enrolled 174 children with a mean age of 14 years.  The MRI estimated the liver proton density fat fraction (PDFF).

Key findings:

  • Liver MRI-PDFF correlated with steatosis grade; the correlation was particularly strong at high and low end values.  Thus, a very low MRI-PDFF was highly likely to predict a steatosis grade 0 or 1 while a very high value corresponded to high steatosis levels.
  • Liver MRI-PDFF was weaker in children with stage 2-4 fibrosis than in children with no fibrosis

The editorial notes that this study “is one of hundreds now published in the literature on MRI and NAFLD…The superiority of MR-based methods…over ultrasound is clear.  The question is why are we still ordering abdominal ultrasounds to diagnose NAFLD in children?”  The barriers for usage of MRI include cost, potential sedation, and nonuniform methods for MRI usage.

The paper conclude that “MRI is not yet sufficient to replace liver biopsy in children.”  The editorial also indicates that the MRI era is fast approaching but not viable today.

Take-home point: Due to the huge numbers of patients with pediatric NAFLD, MRI remains a terrific area for research but remains problematic in clinical practice.  Given the expense of MRI, until its use can reduce liver biopsies or improve management, its role is likely to remain limited.

Turner Field

Turner Field

 

Understanding the Reasons for Abnormal Liver Enzymes in Pediatric Inflammatory Bowel Disease

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A recent large single center study (Pusateri AJ et al. JPGN 2015; 60: 592-97) provides some very practical information regarding elevated liver enzymes in the setting of inflammatory bowel disease (IBD).  Because there are some serious liver diseases associated with IBD and due to the potential for liver toxicity from many of the medications, bumps in liver enzymes need to be carefully considered.

This retrospective study with 514 patients indicates that 77% of these elevations are transient. Table 1 lists the definitions (chronicity, severity) and patterns that were analyzed.  Transient elevations were broken down into brief (<30 days), prolonged <180 days, chronic >180 days and either intermittent or continuously abnormal. The three types were the following:

  • Hepatic: elevated ALT and/or AST; normal alkaline phosphatase (AP), GGT, and direct bilirubin (DB)
  • Cholestatic: elevated AP, GGT, and/or DB; normal ALT and AST
  • Mixed

Severity or degree was classified as follows:

  • 1 –peak liver enzyme 0-1 x ULN
  • 2 –peak liver enzyme >1-2 x ULN
  • 3 –peak liver enzyme >2-4 x ULN
  • 4 –peak liver enzyme >4 x ULN

Key findings:

  • 219 of 514 patients had 1 or more episode of abnormal liver enzymes; five patients with preexisting liver disease were excluded from the analysis.
  • Of 214 patients (152 with Crohn’s disease [CD], 62 with Ulcerative colitis [UC]) with abnormalities, 69% had a hepatitic pattern, 8% had a cholestatic pattern, and 23% had a mixed pattern. There was no association between the pattern and the final diagnosis (eg. idiopathic vs defined etiology)
  • Only 128 had adequate data to assess chronicity.  In this group, 77% had transient elevations (CD 75%, UC 80%)
  • 87% of elevations were considered idiopathic.  65% of patients with idiopathic elevation had levels < 2 times ULN.
  • Among patients with levels <2 times ULN, 95.3% had an idiopathic etiology.
  • Among patients with levels >4 times ULN, 63% had a benign idiopathic etiology
  • Figure 1 provides a pie chart of diagnoses.  Among the 12.6% with a specific etiology for elevated liver tests, drug toxicity was the most common reason: 51.9% were considered due to 6-MP therapy, 3.7% due to methotrexate, 3.7% due to acetaminophen.
  • Other identified causes among the 12.6% with a defined etiology included NAFLD in 11.1%, infections (CMV,EBV, Histoplasmosis) in 14.8%, cholelithiasis in 3.7%, autoimmune hepatitis in 3.7%, primary sclerosing cholangitis/overlap in 3.7%, and vascular malformation in 3.7%.

As with any retrospective study, there are a number of limitations, especially underdiagnosis given a lack of uniform approach to evaluation.  That being said, all patients had a minimum follow-up of at least nine months and most patients with prolonged liver enzyme elevation would have been examined closely.

Bottomline: This study provides reassurance that liver enzyme elevations are common in children with IBD, occurring in >40% of patients over 3 years at this center; most often these elevations are benign and transient.

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