13C-Methacetin Breath Test for the Prediction of Outcome in in ALI or ALF

The importance of identifying the patient with with ALI or ALF who is likely to die without a
liver transplant cannot be overstated and has remained a primary focus of clinical
investigation for 25 years. A recent analysis also conducted by the Acute Liver Failure Study
Group (ALFSG) found that poor outcomes in the ALI patients are less frequent than is observed
in the ALF population. However, in cases where ALI was not related to an acetaminophen (APAP)
overdose, progression to poor outcomes was similar. Traditional scoring systems and
prognostic models, such as King's College Criteria (KCC), Sequential Organ Failure Assessment
(SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II), currently used to
monitor patients with ALF lack individual sensitivity and specificity and do not provide
direct information about the liver's metabolic function, which is a key variable in assessing
liver status and potential disease progression versus recovery in ALF patients. Despite
recent advances used by the ALFSG Prognostic Index (ALFSG-PI), ALI Prognostic Index (ALI-PI)
and Model for End-Stage Liver Disease (MELD), better predictive modalities are still needed.

The 13C-Methacetin breath test is a rapid, reproducible, point-of-care test of liver
metabolic function. After oral or naso-enteric/orogastric tube administration, the 13C
labeled Methacetin is O-demethylated by cytochrome P4501A2 in the liver and further
biotransformed into 13CO2, which is expired in breath. The BreathID® MCS device captures and
quantifies expired 13CO2 and standardizes recovery against expired 12CO2 through a nasal
cannula (in conscious patients) or an adaptor connected to the ventilator line (for intubated
patients). The results obtained from the device are expressed as delta over baseline (DOB),
which expresses the change in 13CO2/12CO2 ratio in comparison to the baseline measurement. It
can be transformed into the percentage of 13C dose recovered over time (PDR) after the
ingestion of Methacetin, and the cumulative PDR (CPRD), the rate at which 13C substrate is
metabolized, derived from the breath 13C/12C ratio.

This is a multicenter, open label, non-randomized study of the MBT to assess functional
trends of liver metabolism in patients diagnosed with severe acute liver injury not related
to acetaminophen overdose (non-APAP ALI) or acute liver failure (ALF). Up to 200 evaluable
patients with non-APAP ALI or ALF present at the time of enrollment into the ALFSG Registry
will be consecutively enrolled. An evaluable patient is one who has completed one or more
Breath Tests measured for a minimum of 30 (and ideally 60) minutes after administration of
the 13C-Methacetin solution. Study sites will include up to 11 of the clinical sites located
in the United States that are involved in the ALFSG.

The Breath Test will be performed up to five times during the study period on all enrolled
subjects. The first Breath Test will be performed as close to the time of study enrollment as
possible upon admission into the study (Day 1). The Breath Test will be repeated on Days 2,
3, 5 and 7 as close as possible to the same time of day as the first Breath Test. If a
subject who is enrolled into the ALFSG-MBT Trial with non-APAP ALI converts to ALF, breath
test collection will continue until a maximum of five Breath Tests have been performed. If an
enrolled non-APAP ALI or ALF subject receives a liver transplant, is discharged/transferred
from the hospital or dies prior to Day 7, no additional Breath Tests will be performed.
Enrolled patients will be contacted for the Day 21 follow up (21 days after the subject's
enrollment into the trial) to determine spontaneous survival, transplantation and occurrence
of serious adverse events since the subject's last study treatment.

Inclusion Criteria:

1. Adult men or women (18-80 years of age)

2. Severe acute liver injury not related to acetaminophen overdose: INR ≥2.0; no evidence
of HE

3. Acute liver failure: INR ≥1.5; presence of any degree of HE

4. Duration of illness <26 weeks

5. Enrolled into the ALFSG Registry.

6. Written informed consent from the patient or patient's legally authorized
representative or family member as defined in the Federal Register Number 21CFR50.3(m)

Exclusion Criteria:

1. Evidence of pre-existing chronic liver disease

2. Pre-existing New York Heart Association stage III/IV heart failure

3. Evidence of pre-existing chronic renal failure

4. Chronic hemodialysis prior to hospital admission

5. Evidence of cirrhosis (unless clinically acute Wilson disease or autoimmune non-APAP
ALI or ALF)

6. Severe obstructive lung disease (FEV1 <50% of predicted on previous spirometry)

7. Severe shock, defined as mean arterial pressure (MAP) <70 mmHg despite >15 µg/kg/min
dopamine, >0.1 µg/kg/min epinephrine, or >0.1 norepinephrine µg/kg/min

8. Extensive small bowel resection (>50 cm)

9. Any evidence of upper GI bleeding at enrollment requiring intervention (endoscopy or
RBC transfusion specifically for upper GI bleeding)

10. Liver transplantation (LT) prior to enrollment. (Note: Listing for LT does not
preclude participation in the trial.)

11. Pregnancy or breastfeeding women (Note: Pregnancy related non-APAP ALI or ALF may be
considered for entry following the delivery of the baby and assuming the mother does
not wish to breastfeed or collect breast milk during the study period.)

12. Allergic to acetaminophen (such as Tylenol® or any other acetaminophen-containing
medications)

13. Participation in other clinical studies evaluating other experimental treatments or
procedures. (Note: Participation in observatory studies is not an exclusion.)

14. Patients in whom enteral drugs or fluids are contra-indicated or the patient either
does not have an appropriately placed naso-enteric/orogastric tube in situ or cannot
tolerate taking the drug preparation orally (200 ml)

15. Budd-Chiari Syndrome

16. Non-APAP ALI or ALF caused by malignancy

17. Moderate and severe adult respiratory distress syndrome (ARDS), as defined by Berlin
Criteria.

18. Subjects who have received amiodarone in the 30 days prior to study enrollment

19. Consumption of any food or beverage that contains caffeine in the 24 hours prior to
enrollment

20. Consumption of any of the following drugs that may interfere with the metabolism of
13C-Methacetin in the 48 hours prior to study enrollment including: allopurinol,
carbamazepine, cimetidine, ciprofloxacin, daidzein, disulfiram, Echinacea, enoxacin,
fluvoxamine, methoxsalen, mexiletine, montelukast, norfloxacin, phenylpropanolamine,
phenytoin, propafenone, rifampin, terbinafine, ticlopidine, thiabendazole, verapamil,
zileuton or oral contraceptives

21. Consumption of alcohol in the 24 hours prior to enrollment

22. Smoking cigarettes in the 8 hours prior to enrollment.