Gene Replacement Therapy for Spinal Muscular Atrophy and Subacute Liver Failure

A recent study (AG Feldman et al. J Pediatr 2020; 225: 252-258. Subacute Liver Failure Following Gene Replacement Therapy for Spinal Muscular Atrophy Type 1) describes two children who developed subacute liver failure after treatment with onasemnogene (AVXS-101). This gene therapy was approved by the FDA in 2019 and more than 335 children have been treated. Both children presented about 3-8 weeks after their AVXS-101 infusion (despite steroid therapy), at 6 months of age and 20 months of age respectively, with ALT values above 1600 and INR of at least 1.5 (despite Vitamin K). Both had liver biospies and then were treated with methylprednisolone, starting at 20 mg/kg/day.

Key points:

  • The authors speculate that subacute liver failure was due to a systemic hyperinflammatory reaction
  • The authors recommend screening prior to AVXS-101 therapy with LFTs, GGT, and INR; if baseline labs are elevated, further workup is recommended (eg. A1AT, HBV, HCV, ANA, anti-SMA, anti-LKM, and ultraound)
  • While this reaction has been with AVXS-101, there are other gene therapies with adenovirus-vector which could trigger similar reactions
  • The authors note that the “package insert for onasemnogene recommends prednisolone (1 mg/kg/day) should be given in the 24 hours before infusion and should be continued for 30 days after infusion.”
  • After infusion, it is “necessary to monitor liver tests frequently in the first 2 months”

My take: This new therapy’s risks are substantial; however, the benefits from treatment can be life-altering as well.

Related blog post: Understanding the New Therapies for Spinal Muscular Atrophy

Word of Caution with New Hepatitis C Medications

From NY Times: Are New Drugs for Hepatitis C Safe? A Report Raises Concerns

An excerpt:

Drugs approved in recent years that can cure hepatitis C may have severe side effects, including liver failure, a new report suggests. The number of adverse events appears relatively small, and the findings are not conclusive. But experts said the report was a warning that should not be ignored…

The report will be published online on Wednesday [1/25/17] by the Institute for Safe Medication Practices, a nonprofit in Horsham, Pa., that studies drug safety. Its findings are based on the group’s analysis of the Food and Drug Administration’s database of reports from doctors around the world of adverse events that might be related to medications.

In October, the F.D.A. identified the first major safety problem caused by the nine antiviral drugs. In 24 patients, the drugs wiped out hepatitis C — but also reactivated hepatitis B infections that had been dormant. Two of those patients died, and one needed a liver transplant. The agency said there were probably additional cases that had not been reported.

As a result, the agency required that a boxed warning, its most prominent advisory, be added to the labeling of the newer antivirals, telling doctors to screen and monitor for hepatitis B in all patients taking the drugs for hepatitis C. Infection with both viruses is not common, and how the reactivation occurs is not known. The problem was not detected during premarket testing of the drugs because patients who currently had hepatitis B or who had a history of it were not allowed into the studies…

The other cases of liver failure are a separate problem. He said it was important for doctors prescribing the newer drugs to test patients’ liver function thoroughly first, because liver disease can be deceptive

My take: Overall, these newer Hepatitis C medications represent a tremendous achievement.  However, as with most medications, rare serious problems can occur and in some cases may be preventable.

Related blog posts:

From Twitter Feed-Funny Church Signs

From Twitter Feed-Funny Church Signs

When death is on the line

“Never go against a Sicilian when death is on the line“! –from The Princess Bride

With acetaminophen-induced hepatic failure, King’s College Hospital (KCH) Criteria have been helpful for predicting death.  While the Sequential Organ Failure Assessment (SOFA) was not designed by a Sicilian (to the best of my knowledge), it is more sensitive at predicting death than KCH Criteria (Liver Transplantation 2012; 18: 405-412, & editorial 384-86) .

SOFA measures organ dysfunction by evaluating each of the following on a 0-4 scale: respiratory, hepatic, coagulation, cardiovascular, neurologic, and renal.

In the cited study, 125 consecutive adult patients (mean age 38 years) with acetaminophen-induced acute liver failure were evaluated.  KCH criteria had highest specificity (83%) and lowest sensitivity (47%).  The SOFA score had the best discriminative ability.  A SOFA score >7 during the first 96 hours predicted death or transplantation with a 95% sensitivity and 70.5% specificity.  Other specific predictors of poor outcome included higher lactate levels, worsened coagulation parameters, and need for mechanical ventilation.  In this cohort, 67 (54%) survived with medical management, 35 (28%) died and 23 (18%) received a liver transplant.

While sensitivity and specificity will vary based on pretest probability/specific population, what is clear is that relying on KCH criteria alone would be unwise.

Additional references:

  • -J Pediatr 2011; 159: 813.  Study of ALF in young infants.  38% were indeterminate, ~14% NH, 12% herpes.  n=148. 60% survived w/o OLT, 24% died, 16% OLT
  • -Hepatology 2010; 53: 567.  18% of indeterminate ALF may be due to acetaminophen toxicity.
  • The King’s College Criteria identify two groups of patients that have a poor prognosis with acetaminophen induced liver failure (’s_College_Criteria)
  • -J Pediatr 2009; 155:801.  Diagnostic evaluation in ALF  –wide variation.  Often not tested for AIH, wilson’s, HAV, HBV
  • -NEJM 2009; 361: 2105.  Changes in FDA labeling of analgesics.  ~30,000 hospitalizations /yr due to acetaminophen overdose in U.S.  –1/2 inadvertent overdose.  Maximum dose -650mg.
  • -Hepatology 2007; 46: 966.  AASLD public policy.  It is leading cause of acute liver failure in U.S –50% of cases with 30% mortality rate.  500 deaths annually.  10% of cases may occur in those receiving the proper doses. In single year, acetaminophen causes more deaths than all the years of statins.
  • -JAMA 2006; 296: 87-93.  Prospective study of daily 4gm acetaminophen in healthy volunteers.  (stayed at research facility).  ALT >3 ULN in 38%.  Resolved over 6 days.
  • -Liver Transplantation 2006; 12: 682.
    -Hepatology 2005; 42: 1364-72.  74 pts died & 23 needed Tx during  6 yr period at 22 tertiary care centers.  48% of cases were unintentional overdoses.
  • -J Pediatr 2002; 140: 522.  Predictors of outcome p acetaminophen ingestion.

The more you know the more you see

And the more you see, the more you know.  Case in point: gestational alloimmune liver disease (GALD), also referred to as congenital alloimmune hepatitis (CAH) which itself is often referred to as neonatal hemochromatosis (NH).  Now, GALD is more readily identifiable and has better treatments to prevent progression to liver-related complications.  A recent study (J Pediatr 2011; 159: 612-16) shows that GALD can result in fetal death; this finding is a relatively logical extension from the work in this area over the last decade but would not have been feasible without the prior recognition that most cases of neonatal hemochromatosis stem from GALD.

GALD is mediated by fetal complement via activation of the terminal complement cascade.  The presence of C5b-9 complex, an antigen that is part of this cascade, is unique to cases of NH and allows diagnosis, particularly in case in which extrahepatic siderosis is not present. In the reference above, a retrospective study enabled autopsies of six stillborn fetuses and two extreme premature infants who had family histories compatible with NH (along with appropriate controls); the autopsy cases were identified as having GALD– based on liver immunostains with C5b-9 complex.  The implications of this study for pediatricians:

  • When faced with a newborn with coagulopathy or liver failure with family history of stillbirth, consider linking the events immediately & evaluate for NH.  However, this clue has limited utility as NH is the most frequent reason for liver failure in newborns; though, many  newborns with liver failure are often treated for sepsis prior to consideration of NH.
  • Establishing a proper diagnosis, allows management of subsequent pregnancies.  GALD is extremely likely to recur in subsequent pregnancies & can be treated by administration of IVIG to expectant at-risk mothers.

Additional references:

  • -J Pediatr 2011; 159: 813.  Study of ALF in young infants.  38% were indeterminate, ~14% NH, 12% herpes.  n=148. 60% survived w/o OLT, 24% died, 16% OLT
  • -Hepatology 2010; 51: 2061 (edit 1888). Fetal hepatocyte injury involves terminal complement cascade –very good article from Whittington et al. NH being renamed ‘congenital alloimmune hepatitis’
  • -J Pediatr 2009; 155: 566-71. n=16. 75% with good outcome –Rx’d with IVIG (1gm/kg) and exchange transfusion (7 had double volume ET and 6 had less). Appeared to reduce need for liver transplant. Some response with regard to hypoglycemia was fairly quick but most parameters like coagulopathy improved slowly ~2 weeks. Previous historical survival ~36%. (5 of 10 w transplant and 2 of 9 w/o transplant).
  • -Pediatrics 2008; 121: e1615. Weekly IVIG during pregnancy after 18th week of gestation very effective in preventing severe NH
  • -Hepatology 2006; 43: 654. Review by Whitington. MRI detects disease in ~90%. Mucosal biopsy abnl in about 2/3rds of patients. Explains iron homeostasis and alloimmunity.
  • -Liver Tx 2005; 11: 1323 (ed), 1417. Medical treatment ineffective, try transplant. “All who drink of this remedy recover in a short time except those whom it does not help, who all die. It is obvious, therefore, that it fails only in incurable cases.” –Galen, circa 100AD
  • -JPGN 2005; 40: 544. NH is probably an alloimmune dz.
  • -Lancet 2004; 364: 1690-8.