In a twenty-eighth embodiment, provided is a pharmaceutical composition according to the twenty-sixth or twenty-seventh embodiment, wherein the microcrystalline cellulose is present in an amount from about 49 wt % to about 51 wt %. Alternatively, provided is a pharmaceutical composition according to the twenty-sixth or twenty-seventh embodiment, wherein the microcrystalline cellulose is present in an amount of about 51 wt %.

In a twenty-ninth embodiment, provided is a pharmaceutical composition according to the twenty-sixth embodiment, wherein the croscarmellose sodium is present in an amount from about 4 wt % to about 6 wt %. Alternatively, provided is a pharmaceutical composition according to the twenty-sixth embodiment, wherein the croscarmellose sodium is present in an amount of about 5 wt %.

In a thirtieth embodiment, provided is a pharmaceutical composition according to the twenty-sixth or twenty-ninth embodiment, wherein the microcrystalline cellulose is present in an amount from about 53 wt % to about 55 wt %. Alternatively, provided is a pharmaceutical composition according to the twenty-sixth or twenty-ninth embodiment, wherein the microcrystalline cellulose is present in an amount of about 54 wt %.

In a thirty-first embodiment, provided is a pharmaceutical composition according to the twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, or thirtieth embodiment, wherein colloidal silicon dioxide is present in an amount of about 0.20 wt %.

In a thirty-second embodiment, provided is a pharmaceutical composition according to the twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth, or thirty-first embodiment, wherein the magnesium stearate is present in an amount of about 0.50 wt %.

In a thirty-third embodiment, provided is a pharmaceutical composition according to the twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth, thirty-first, or thirty-second embodiment, wherein the rifaximin is present in an amount of about 17 wt %.

In a thirty-fourth embodiment, provided is a pharmaceutical composition according to the twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth, thirty-first, thirty-second, or thirty-third embodiment, wherein the HMPC-AS is present in an amount of about 17 wt %.

In a thirty-fifth embodiment, provided is a pharmaceutical composition according to the twenty-sixth, twenty-seventh, twenty-eighth, twenty-ninth, thirtieth, thirty-first, thirty-second, thirty-third, or thirty-fourth embodiment, wherein the total amount of rifaximin is 40 mg.

In a thirty-sixth embodiment, the pharmaceutical compositions described herein are in the form of a tablet.

In a thirty-seventh embodiment, the pharmaceutical compositions described herein are in the form of a tablet, and are immediate release or sustained extended release. In one alternative, the pharmaceutical composition is a sustained extended release tablet.

In a thirty-eighth embodiment, the pharmaceutical compositions described herein are film coated. Coatings are known to those of skill in the art and may immediate release or sustained release coatings. An example of a film coating is Opadry II Blue 85F90614 by Colorcon®.

Other solid dispersions and pharmaceutical compositions included in the present disclosure are described in the Exemplification section below.

Uses, Formulation and Administration Dosage Forms

According to other embodiments, the present disclosure relates to a method of using the disclosed solid dispersions pharmaceutical compositions thereof to prevent complications of liver cirrhosis such as e.g., in subjects with early decompensation.

Also provided herein are methods of using the solid dispersions and pharmaceutical compositions thereof to prevent all-cause mortality e.g., in subjects with liver cirrhosis who may also have early decompensation.

Also provided herein are methods of using the solid dispersions and pharmaceutical compositions thereof to reduce the time to hospitalization that is associated with complications of liver disease (e.g., liver cirrhosis complications) such as e.g., reducing the time to hospitalization from one or more of hepatic encephalopathy (HE), esophageal variceal bleeding (EVB), spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome (HRS).

Also provided herein are methods of using the solid dispersions and

pharmaceutical compositions thereof to prevent hospitalization that is associated with complications of liver disease (e.g., liver cirrhosis complications) such as e.g., reducing the time to hospitalization from one or more of hepatic encephalopathy (HE), esophageal variceal bleeding (EVB), spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome (HRS).

Also provided herein are methods of using the solid dispersions and pharmaceutical compositions thereof to reduce the time to all-cause mortality that is associated with complications of liver disease (e.g., liver cirrhosis complications) such as e.g., reducing the time to all-cause mortality from one or more of hepatic encephalopathy (HE), esophageal variceal bleeding (EVB), spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome (HRS).

Also provided herein are methods of using the solid dispersions and pharmaceutical compositions thereof to prevent all-cause mortality that is associated with complications of liver disease (e.g., liver cirrhosis complications) such as e.g., reducing the time to all-cause mortality from one or more of hepatic encephalopathy (HE), esophageal variceal bleeding (EVB), spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome (HRS).

Further provided are methods of using the solid dispersions and pharmaceutical compositions thereof to reduce the time to development of refractory ascites in e.g., subjects having early decompensated liver cirrhosis or liver cirrhosis complications such as HE, EVB, SBP, or HRS.

Suitable dosage forms that can be used with the solid dispersions and compositions herein include, but are not limited to, capsules, tablets, mini-tablets, beads, beadlets, pellets, granules, granulates, and powder. Suitable dosage forms may be coated, for example using an enteric coating. In some embodiments, the solid dispersions and compositions are formulated as tablets, caplets, or capsules. In one embodiment, the solid dispersions and compositions are formulated as a tablet.

Provided compositions may be formulated such that a dosage of between 0.001-100 mg/kg body weight/day of the inhibitor can be administered to a patient receiving these compositions. It should also be understood that a specific dosage and treatment regimen for any particular patient will depend upon a variety of factors, including age, body weight, general health, sex, diet, time of administration, rate of excretion, drug combination, the judgment of the treating physician, and the severity of the particular disease being treated. The amount of a provided dispersion in the composition will also depend upon the particular compound in the composition. In one aspect, the dosage amount of rifaximin in a provided composition is 40 mg. In another aspect, the dosage amount of rifaximin in a provided composition is 80 mg.

EXEMPLIFICATION
General Preparation of Solid Dispersions

The solid dispersions described herein can be prepared by a number of methods, including by melting and solvent evaporation. The solid dispersions of the present invention can also be prepared according to the procedures described in: Chiou WL, Riegelman S: “Pharmaceutical applications of solid dispersion systems”, J. Pharm. Sci. 1971; 60:1281-1302; Serajuddin ATM: “Solid dispersion of poorly water-soluble drugs: early promises, subsequent problems, and recent breakthroughs”, J. Pharm. Sci. 1999; 88:1058-1066; Leuner C, Dressman J: “Improving drug solubility for oral delivery using solid dispersions”, Eur. J. Pharm. Biopharm. 2000; 50:47-60; and Vasconcelos T, Sarmento B, Costa P: “Solid dispersions as strategy to improve oral bioavailability of poor water soluble drugs”, Drug Discovery Today 2007; 12:1068-1075, all of which are incorporated herein by reference in their entireties.

In one aspect, the components, e.g., rifaximin, polymer and methanol are mixed and then spray dried. Exemplary conditions are summarized in Table 1 below.

Exemplary Spray Drying Process Parameters, include for example:

- Spray Dryer—e.g., PSD 1;
- Single or multi-fluid nozzle: e.g., a two Fluid Niro Nozzle;
- Nozzle orifice—0.1-10 mm;
- Inlet gas temperature—75-150+5 deg C;
- Process gas flow (mmH2O)—20-70, preferred 44;
- Atomizing gas pressure—0.7-1 bar;
- Feed rate—2-7 kg/Hr;
- Outlet temperature—30-70±3 deg C;
- Solution temperature—20-50 deg C; and
  
  Post spray drying vacuum dry at 20-60 deg C, for between about 2 and 72 hrs.

TABLE 1

Inlet
Aspir-

Inlet temp.
Outlet temp.
Spray

Description
temp.
ator
Pump
(measured,
(measured,
rate (b)

(a)
(set, ° C.)
%
%
° C.)
° C.)
mL/min

(50:50)
120
95
40-30
120-119
60-45
9.6

HPMC-AS:

rifaximin,

~10 g scale

(a): approximate ratio of rifaximin to HPMC-AS, by weight.

(b): flow rates are estimated at 30% pump.

A representative batch formula is provided in Table 2.

TABLE 2

Theoretical

Quantity

Ingredient
Function
% w/w
(kg/batch)

Rifaximin
Active
47.20
22.18

HPMC-AS
Polymer
47.20
22.18

Poloxamer 407
Surfactant
5.60
2.64

Methanol^a
Solvent
—
(438.0)

Nitrogen^b
Process gas
—
—

Total Theoretical Weight
100.00
47.00

^aRemoved during drying process; process gas for drying and atomization; not incorporated in product

Blending/Encapsulation Procedure

The components and composition of an 80 mg and 40 mg immediate and sustained extended release tables are proved in Table 3 below.

TABLE 3

Theoretical Quantity (mg/tablet)

80 mg-
80 mg-
40 mg-
40 mg-

Ingredient
Function
IR
SER
IR
SER

Rifaximin
Active
80
80
40
40

HPMC-AS
Polymer
80
80
40
40

Poloxamer 407
Surfactant
9.49
9.49
4.75
4.75

Croscarmellose
Dissolution
30.15
11.33
20.74
11.33

sodium
enhancer

Microcrystalline
Filler
25.28
44.10
119.43
128.84

cellulose

Colloidal silicon
Glidant
0.45
0.45
0.45
0.45

dioxide

Magnesium
Lubricant
1.13
1.13
1.13
1.13

stearate

(non-bovine)

Opadry II Blue
Coating
11.92
11.92
11.92
11.92

85F90614

(PVA coating)

Purified Water
Solvent for
—
—
—
—

coating

solution

Total Theoretical Weight
238.42
238.42
238.42
238.42

Clinical Data

The following data was obtained using the compositions described in Table 3.

A Phase 2, randomized, double-blind, placebo-controlled, parallel multicenter study evaluation of the efficacy (prevention of hospitalization for complications of liver cirrhosis or all-cause mortality in subjects with early decompensation) and safety of rifaximin SSD tablets in subjects with early decompensated liver cirrhosis was conducted. Subjects with documented ascites who had not previously experienced SBP, EVB, or HRS were enrolled in the study. Subjects completed a 1 to 21-day Screening Period, a 24-week Treatment Period, and a 2-week Follow-up Period. Approximately 420 subjects who successfully completed the Screening Period were randomized in a 1:1:1:1:1:1 allocation to 1 of 6 treatment groups and entered the Treatment Period. All treatments were administered once daily at bedtime. Assessments of efficacy and safety were performed during clinic visits at Day 1 (baseline), Weeks 2, 4, 8, 12, 16, 20, and 24 (End of Treatment [EOT]). All subjects completed an End of Study (EOS) visit at Week 26 (or early termination if applicable) for final safety assessments.

Inclusion Criteria

A subject was eligible for inclusion in this study if he/she met all of the following criteria:

- 1. Subject was ≥18 years of age.
- 2. Subject was male or female.
  - Females of childbearing (reproductive) potential had to have a negative serum pregnancy test at Screening and had to agree to use an acceptable method of contraception throughout their participation in the study. Acceptable methods of contraception included double barrier methods (condom with spermicidal jelly or a diaphragm with spermicide), hormonal methods (eg, oral contraceptives, patches or medroxyprogesterone acetate), or an intrauterine device (IUD) with a documented failure rate of less than 1% per year. Abstinence or partner(s) with a vasectomy could be considered an acceptable method of contraception at the discretion of the investigator. Note: Females who had been surgically sterilized (eg, hysterectomy or bilateral tubal ligation) or who were postmenopausal (total cessation of menses for >1 year) were not considered “females of childbearing potential.”
- 3. Subject had a diagnosis of liver cirrhosis and documented ascites, either by imaging study or physical exam (Note: Subjects with Grade 1 ascites were permitted in the study), but had not yet experienced any of the following complications of cirrhosis:
  - EVB—clinically significant gastrointestinal bleed
  - SBP—greater than 250 polymorphonuclear (PMN) cells/mm3 and/or positive monomicrobial culture in the ascitic fluid
  - Renal failure in the presence of ascites-rise in the serum creatinine by 0.5 mg/dL (to greater than 1.5 mg/dL), with ascites documented on physical examination, imaging, and/or admitted on diuretics for the treatment of ascites
  - Development of medically refractory ascites.
- 4. Subject had a MELD score of ≥12, a MELDNa score of ≥12, or a Child-Pugh B Classification (score=7-9).
- 5. Subject was capable of understanding the requirements of the study, and was willing to comply with all study procedures.
- 6. Subject understood the language of the informed consent form, and was capable and willing to sign the informed consent form.
- 7. If applicable, subject had a close family member or other personal contact that could provide continuing oversight to the subject and was available to the subject during the conduct of the trial.

Exclusion Criteria

A subject was not eligible for inclusion in this study if any of the following criteria applied:

- 1. Subject had a history of a major psychiatric disorder, including uncontrolled major depression or controlled or uncontrolled psychoses within the past 24 months prior to signing the informed consent (Diagnostic and Statistical Manual of Mental Disorders, 4th.) that, in the opinion of the investigator, would prevent completion of the study, interfere with analysis of study results, or negatively impact the subject's participation in the study.
- 2. Subject had history of alcohol abuse or substance abuse within the past 3 months prior to signing the informed consent (Diagnostic and Statistical Manual of Mental Disorders, 4th.).
- 3. Subject had documented primary sclerosing cholangitis (Note: subjects with primary biliary cirrhosis were allowed in the study).
- 4. Subject had undergone prophylactic variceal banding within 2 weeks of Screening or was scheduled to undergo prophylactic variceal banding during the study (Note: subjects with previous prophylactic variceal banding were allowed to participate in the study).
- 5. Subject had been diagnosed with an infection for which they are currently taking oral or parenteral antibiotics.
- 6. Subject had significant hypovolemia, or any electrolyte abnormality that could affect mental function (eg, serum sodium<125 mEq/L, serum calcium>10 mg/dL).
- 7. Subject had severe hypokalemia as defined by a serum potassium concentration<2.5 mEq/L.
- 8. Subject was anemic, as defined by a hemoglobin concentration of ≤8 g/dL.
- 9. Subject had renal insufficiency with a creatinine of ≥1.5 mg/dL.
  - Note: Laboratory tests related to Inclusion/Exclusion criteria could be repeated once, before considering subject as a Screening Failure (given all other Inclusion/Exclusion criteria are met/not met respectively) at the discretion of the Investigator.
- 10. Subject showed presence of intestinal obstruction or has inflammatory bowel disease.
- 11. Subject had Type 1 or Type 2 diabetes that was poorly controlled in the opinion of the investigator or had had an HbAlc>12% within the past 3 months prior to Screening or at the Screening visit.
- 12. Subject had a history of seizure disorders.
- 13. Subject had unstable cardiovascular or pulmonary disease, categorized by a worsening in the disease condition that required a change in treatment or medical care within 30 days of randomization.
- 14. Subject had an active malignancy within the last 5 years (exceptions: basal cell carcinomas of the skin, or if female, in situ cervical carcinoma that had been surgically excised).
- 15. Subject had hepatocellular carcinoma (HCC). Note: Alpha-fetoprotein (AFP) concentration was measured at Screening. If the AFP was greater than 200 ng/ml, the subject was excluded from participation in the study. If the AFP was above the upper limit of normal and ≤200 ng/mL, cross-sectional imaging or ultrasonography techniques had to be used to rule out HCC.
- 16. Subject had any condition or circumstance that adversely affected the subject or could cause noncompliance with treatment or visits, could affect the interpretation of clinical data, or could otherwise contraindicate the subject's participation in the study.
- 17. If female, subject was pregnant or at risk of pregnancy, or was lactating.
- 18. Known varicella, herpes zoster, or other severe viral infection within 6 weeks of randomization.
- 19. Known human immunodeficiency virus (HIV) infection.
- 20. Subject had a positive stool test for Yersinia enterocolitica, Campylobacter jejuni, Salmonella, Shigella, ovum and parasites, and/or Clostridium difficile.
  
  NOTE: Results of stool tests had to be confirmed as negative prior to randomization.
- 21. Subject had a history of tuberculosis infection and/or had received treatment for a tuberculosis infection. If subject had a previous positive skin test for tuberculosis antigen then they were to have a current negative chest X-ray to be eligible and could not have received previous treatment.
- 22. Subject was an employee of the site that was directly involved in the management, administration, or support of this study or was an immediate family member of the same.
- 23. Subject had a history of hypersensitivity to rifaximin, rifampin, rifamycin antimicrobial agents, or any of the components of rifaximin SSD.
- 24. Subject used any investigational product or device, or participated in another research study within 30 days prior to randomization.
- 25. Subject had a documented overt HE episode (Conn score≥2) that had not resolved within 30 days of Visit 1 (Screening).

Treatments Administered

There were 6 treatment groups as listed below. The compositional components are presented above in Table 3. All treatments were to be administered orally qhs (at every bedtime). The duration of the treatment was 24 weeks.

- Treatment A: rifaximin SSD 40 mg qhs (IR (immediate release) tablet)
- Treatment B: rifaximin SSD 80 mg qhs (IR tablet)
- Treatment C: rifaximin SSD 40 mg qhs (SER (sustained extended release) tablet)
- Treatment D: rifaximin SSD 80 mg qhs (SER tablet)
- Treatment E: rifaximin SSD 80 mg qhs (IR tablet)+rifaximin 80 mg qhs (SER tablet)
- Treatment F: Placebo qhs

Primary Efficacy Endpoints

Over the 24-week treatment period, the primary efficacy endpoint for the study was time to:

- All-cause mortality, or
- Hospitalization that was associated with 1 of the following complications of liver disease:
  - HE—altered mental status diagnosed as HE, and defined as an increase of the Conn score to Grade≥2 (ie, 0 or 1 to ≥2).
  - EVB—occurrence of a clinically significant gastrointestinal bleed was defined as:
    - Bleeding from an esophageal or gastric varix at the time of endoscopy, or.
    - The presence of large varices with blood evident in the stomach, and no other identifiable cause of bleeding observed during endoscopy.
      - In addition, 1 or more of the following criteria had to be present:
      - Drop in hemoglobin of greater than 2 g/dL over the first 48 hours post hospital admission,
      - Transfusion requirement of 2 units of blood or more within 24 hours of hospital admission,
      - A systolic blood pressure of less than 100 mm Hg, or
      - Pulse rate greater than 100 beat/min at the time of admission.
- Note: Baveno IV criteria was also used to further define variceal bleeding episodes.
  - SBP-greater than 250 PMNcells/mm³and/or positive monomicrobial culture in the ascitic fluid.
  - HRS was defined as:
    - Progressive rise in serum creatinine (>1.5 mg/dL) with no improvement after at least 2 days with diuretic withdrawal and volume expansion with albumin;
    - Absence of parenchymal kidney disease;
    - Oliguria;
    - Absence of shock; and
    - No current or recent (within 3 months prior randomization) treatment with nephrotoxic drugs.

Key Secondary Efficacy Endpoints

The key secondary efficacy endpoints of this study were overall hospitalization rate for each of the individual component of the primary endpoint or all-cause mortality over the 24-week treatment period.

Other Secondary Endpoints

Other secondary endpoints of this study were the following:

- Time to first hospitalization or all-cause mortality for each individual component of the primary endpoint.
- All-cause hospitalization rate over the 24-week Treatment Period.
- Liver cirrhosis mortality over the 24-week Treatment Period.
- Time to development of medically refractory ascites, defined as ascites which could either no longer be effectively managed by:
  - A low sodium diet and maximal doses of diuretics (up to 400 mg spironolactone and 160 mg furosemide per day), or
  - Diuretics, due to the inability to tolerate side effects of maximal doses of diuretics.
- Hospitalizations over the 24-week treatment period for all other infections.
- Hospitalization as the result of Acute Kidney Injury (AKI) that was not attributable to HRS and was defined by a rapid reduction (over less than 48 hours) of kidney function as evidenced by:
  - A rise in serum creatinine, (with either an absolute increase in serum creatinine of ≥0.3 mg/dL (≥26.4 μmol/L) or percentage increase in serum creatinine of ≥50%), and
  - A reduction in urine output (defined as <0.5 ml/kg/hr for more than 6 hours).
- Change in indices of Health Outcomes (Chronic Liver Disease Questionnaire (CLDQ_, Gastrointestinal Symptom Rating Scale (GSRS), Caregiver Burden Inventory (CBI), Epworth Sleepiness Scale (ESS)) at Weeks 4, 8, 12, 16, 20 and 24.
- Pharmacokinetics of rifaximin and 25-desacetyl rifaximin assessing effects on factors including hepatic impairment, renal impairment and concomitant medications.
- The critical flicker frequency (CFF) was assessed for each subject. CFF was assessed using a specialized CFF instrument.
- Changes from baseline in blood ammonia concentrations at Weeks 2, 4, 8, 12, 16, 20 and 24.
- Change from baseline in MELD (Model for End-Stage Liver Disease) and MELDNa (model end stage liver disease sodium) score at Weeks 2, 4, 8, 12, 16, 20 and 24.
- Change from baseline in Child-Pugh score at Weeks 2, 4, 8, 12, 16, 20 and 24.

Drug Concentration Measurements

Rifaximin and metabolite concentration data was collected according to the Full Population PK Sampling design recommended in the FDA Guidance for Industry: Population Pharmacokinetics.

Disposition of Subjects

A total of 518 subjects were randomized in the study, of which 408 (78.8%) completed the study:

- 64 subjects in the 40 mg qhs IR group,
- 63 subjects in the 80 mg qhs IR group,
- 68 subjects in the 40 mg qhs SER group,
- 68 subjects in the 40 mg qhs SER group, 7
- 2 subjects in the 80 mg qhs SER group,
- 66 subjects in the combined IR/SER group and
- 75 subjects in the placebo group.

In total, 109 (21.0%) subjects prematurely discontinued from the study, with the largest number of discontinuations observed in the 80 mg qhs IR group (30.4%). The most common reason of premature discontinuation reported in the study was “withdrawal by subject”; this accounted for the premature discontinuation of 44 (8.5%) of all subjects that were randomized. This was followed by “death” which accounted for the premature discontinuation of 21 (4.1%) of all randomized subjects. Of all treatment groups, the 80 mg qhs IR group experienced the most number of premature discontinuations from the study (28 subjects in total), with “withdrawal by subject” reported as the most common reason of premature discontinuation (n=9).

Data Sets Analyzed

Two datasets were analyzed: ITT population and PP populations.

- ITT population was defined as all randomized subjects who took at least 1 dose of study drug.
- PP population was defined as all subjects in the ITT population with the exception of those who failed to meet inclusion criteria 3 or 4, or meet exclusion criterion 1.
- Safety population included all randomized subjects who took at least 1 dose of study drug.

The analyses of baseline characteristics and efficacy were performed on the ITT population. The primary efficacy analyses were also performed on the PP population as a sensitivity analysis.

Analysis of Efficacy

The primary efficacy endpoint was the time to all-cause mortality or hospitalization that was associated with 1 of the following complications of liver disease: HE, EVB, SBP, or HRS over the 24-week treatment period was performed on the ITT population.

The primary analysis of time to hospitalization for any of the liver cirrhosis complications or all-cause mortality specified for the primary endpoint utilized a log-rank test stratified by analysis region (2-sided test at a significance level of 0.05).

Pairwise treatment group comparisons (each of the rifaximin SSD groups versus placebo) utilizing the log-rank test was also performed.

Additionally, Kaplan-Meier methods were used to estimate the proportion of subjects experiencing hospitalization for any of the liver cirrhosis complications or all-cause mortality on Days 28, 56, 84, 112, 140, and 168 for each treatment group.

Other analyses of the primary efficacy endpoint include sensitivity analyses (primary efficacy endpoint analyses using PP population) and prespecified subgroup analyses.

Time to Hospitalization for any of the Liver Cirrhosis Complications or all-cause Mortality

The primary efficacy endpoint was the time to all-cause mortality or hospitalization that was associated with 1 of the following complications of liver disease: HE, EVB, SBP, or HRS over the 24-week treatment period. Subjects who terminated early for reasons other than death were contacted approximately 24 weeks from randomization to determine if they experienced the primary endpoint. In the case of a subject's death, the subject's caregiver (if applicable) was contacted.

The time to hospitalization for any of the liver cirrhosis complications or all-cause mortality was defined as the duration between the date of first dose of the study drug and the date of first hospitalization for any of the liver cirrhosis complications or all-cause mortality.

Subjects who completed the entire 24-week treatment period without death or meeting the definition of liver cirrhosis complications of HE, EVB, SBP, or HRS were censored at the date of final visit (date of last contact). Subjects who prematurely discontinued before the end of the 24-week treatment period for reasons other than death were contacted monthly via a follow-up phone call for capture of cirrhosis complications, hospitalization, or death information. Subjects who did not meet the primary endpoint were censored at the date of last contact.

Primary Efficacy Analysis

The primary analysis did not demonstrate an overall statistically significant difference in time to hospitalization for any of the liver cirrhosis complications or all-cause mortality up to 24 weeks in any group. The overall treatment comparison effect for any of the rifaximin SSD treatments versus placebo was not statistically significant (stratified log-rank p=0.8062) (Table 4). FIG. 1 presents a Kaplan-Meier estimate for the distribution of time to hospitalization for any of the liver cirrhosis complications by treatment group for the ITT population. Based on the Kaplan-Meier estimates, the SER 80 mg qhs treatment group presented with the highest survival rate of all treatment groups and the combined IR/SER treatment group had the lowest survival rate; however this effect was not statistically significant (log-rank p=0.2262). FIG. 2 presents a Kaplan-Meier estimate for the distribution of time to all-cause mortality by treatment group for the ITT population. Based on the Kaplan-Meier estimates, the placebo group presented with the highest survival rate followed by the SER 80 mg qhs treatment group and the combined IR/SER treatment group had the lowest survival rate; however this effect was not statistically significant (log-rank p=0.7573). FIG. 3 presents a Kaplan-Meier estimate for the distribution of time to hospitalization for any of the liver cirrhosis complications or all-cause mortality by treatment group for the ITT population. Based on the Kaplan-Meier estimates, the SER 80 mg qhs treatment group presented with the highest survival rate and the combined IR/SER treatment group had the lowest survival rate; this effect was statistically significant (log-rank p=0.0420).

Supportive Analysis Based on the PP Population

The results on the primary efficacy analysis based on the PP population were not consistent with the pairwise comparisons based on the ITT population (Table 4). The primary analysis on the PP population demonstrated a statistically significant difference in the time to hospitalization for any of the liver cirrhosis complications or all-cause mortality up to 24 weeks that was in favor of the SER 80 mg qhs treatment group versus placebo (stratified log-rank p=0.0464). There were no other statistically significant pairwise comparisons observed between the remaining active treatment groups and placebo (Table 5). The overall treatment comparison effect for any of the rifaximin SSD treatments versus placebo was not statistically significant (stratified log-rank p=0.9879). FIG. 4 presents a Kaplan-Meier estimate for the distribution of time to hospitalization for any of the liver cirrhosis complications or all-cause mortality by treatment group for the PP population. Based on the Kaplan-Meier estimates, the SER 80 mg qhs treatment group presented with the highest survival rate and the combined IR/SER treatment group had the lowest survival rate; this effect was statistically significant (log-rank p=0.0182).

TABLE 4

Time to Hospitalization for any of the Liver Cirrhosis Complications

or All-cause Mortality up to 24 Weeks-ITT Population

# of
# of
Censored

Subjects
Events
<Week 24
Week 24¹
p-value²

Overall Treatment

Comparison³

Any Rifaximin SSD Treatment
422
50 (11.8%)
31 (7.3%)
341
0.8062

(80.8%)

Placebo
94
10 (10.6%)
11 (11.7%)
73 (77.7%)

Pairwise Comparisons (versus

Placebo)³

Treatment A: Rifaximin SSD
78
7 (9.0%)
5 (6.4%)
66
0.6316

40 mg qhs (IR Tablet)

(84.6%)

Treatment B: Rifaximin SSD
91
15 (16.5%)
9 (9.9%)
67
0.2283

80 mg qhs (IR Tablet)

(73.6%)

Treatment C: Rifaximin SSD
84
9 (10.7%)
7 (8.3%)
68
0.9666

40 mg qhs (SER Tablet)

(81.0%)

Treatment D: Rifaximin SSD
89
4 (4.5%)
6 (6.7%)
79
0.0991

80 mg qhs (SER Tablet)

(88.8%)

Treatment E: Rifaximin SSD
80
15 (18.8%)
4 (5.0%)
61
0.1792

80 mg qhs (IR Tablet) and

(76.3%)

Rifaximin SSD 80 mg qhs

(SER Tablet)

IR = immediate release;

ITT = intent to treat;

qhs = once daily at bedtime;

SER = sustained extended release;

SSD = solid soluble dispersion.

¹Number of subjects censored at Week 24 (subject did not experience an event and was enrolled in the study at Week 24).

²P-value was obtained using a stratified log-rank test.

³Stratified by analysis region (study centers are grouped within 2 regions, centers in the United States and centers in Russia)

TABLE 5

Time to Hospitalization for any of the Liver Cirrhosis Complications

or All-cause Mortality up to 24 Weeks-PP Population

# of
# of
Censored

Subjects
Events
<Week 24
Week 24²
p-value³

Overall Treatment

Comparison⁴

Any Rifaximin SSD
403
46 (11.4%)
31 (7.7%)
326
0.9879

Treatment

(80.9%)

Placebo
90
10 (11.1%)
10
70 (77.8%)

(11.1%)

Pairwise Comparisons (versus

Placebo)⁴

Treatment A: Rifaximin SSD
72
5 (6.9%)
5 (6.9%)
62
0.3116

40 mg qhs (IR Tablet)

(86.1%)

Treatment B: Rifaximin SSD
88
15 (17.0%)
9 (10.2%)
64
0.2247

80 mg qhs (IR Tablet)

(72.7%)

Treatment C: Rifaximin SSD
81
9 (11.1%)
7 (8.6%)
65
0.9641

40 mg qhs (SER Tablet)

(80.2%)

Treatment D: Rifaximin SSD
85
3 (3.5%)
6 (7.1%)
76
0.0464

80 mg qhs (SER Tablet)

(89.4%)

Treatment E: Rifaximin SSD
77
14 (18.2%)
4 (5.2%)
59
0.2523

80 mg qhs (IR Tablet) and

(76.6%)

Rifaximin SSD 80 mg qhs

(SER Tablet)

IR = immediate release;

ITT = intent to treat;

PP = per protocol;

qhs = once daily at bedtime;

SER = sustained extended release;

SSD = solid soluble dispersion.

¹All subjects in the ITT population except those that failed inclusion criteria 3, 4 or met exclusion criterion 1.

²Number of subjects censored at Week 24 (subject did not experience an event and was enrolled in the study at Week 24.

³P-value was obtained using a stratified log-rank test.

⁴Stratified by analysis region (study centers are grouped within 2 regions, centers in the United States and centers in Russia).

Prespecified Subgroup Analyses of the Primary Efficacy Endpoint Baseline MELD Category

The influence of a subject's baseline MELD category on the primary efficacy analysis was evaluated. Baseline MELD subgroups were categorized as MELD scores of ≤10, 11 to 18, 19 to 24, or ≥25. None of the pairwise comparisons versus placebo were statistically significant in any of the subgroups. The overall treatment comparison effect for any of the rifaximin SSD treatment versus placebo was not statistically significant (MELD score of ≤10: stratified log-rank p=0.8486; MELD score: 11 to 18 stratified log-rank p=0.7937; MELD score of 19 to 24: stratified log-rank p=0.3154; and MELD score of ≥25: stratified log-rank p=not applicable [1 event out of 1 subject]).

Baseline MELDNa Category

The influence of a subject's baseline MELDNa category on the primary efficacy analysis was evaluated. Baseline MELDNa subgroups were categorized as MELDNa scores of ≤10, 11 to 18, 19 to 24, or ≥25. None of the pairwise comparisons versus placebo were statistically significant in any of the subgroups. The overall treatment comparison effect for any of the rifaximin SSD treatment versus placebo was not statistically significant (MELDNa score of ≤10: stratified log-rank p=0.3200; MELDNa score: 11 to 18 stratified log-rank p=0.9368; MELDNa score of 19 to 24: stratified log-rank p=0.2608; and MELDNa score of ≥25: stratified log-rank p=not applicable (3 events out of 4 subjects)).

Baseline Child-Pugh Classification

The influence of a subject's baseline Child-Pugh classification on the primary efficacy analysis was evaluated. The baseline Child-Pugh classification subgroups were categorized as Class A, Class B, or Class C. None of the pairwise treatment comparisons versus placebo were statistically significant in any of the subgroups. The overall treatment comparison effect for any of the rifaximin SSD treatments versus placebo was not statistically significant (Class A: stratified log-rank p=not applicable (zero events); Class B: stratified log-rank p=0.7942 and Class C: stratified log-rank p=0.9516).

Baseline Conn Score

The influence of a subject's baseline Conn score on the primary efficacy analysis was evaluated. Baseline Conn score subgroups were categorized as 0, 1, or 2. Table 6 presents the analysis of the primary efficacy endpoint by baseline Conn score. Consistent with the results of the PP population, a statistically significant difference in the time to hospitalization for any of the liver cirrhosis complications or all-cause mortality was observed within the Conn score subgroup 0 and was in favor of the SER 80 mg qhs treatment group versus placebo (stratified log-rank p=0.0460). This statistical significance was not evident within the Conn score subgroups 1 or 2 (although, subgroup 2 had 1 event out of subjects).

The overall treatment comparison effect for any of the rifaximin SSD treatments versus placebo was not statistically significant for any subgroup (Conn score 0: stratified log-rank p=0.8915; Conn score 1: stratified log-rank p=0.8251; Conn score 2: not applicable [1 event out of 2 subjects]).

TABLE 6

Analysis of Primary Efficacy Endpoint: Time to Hospitalization for any of the

Liver Cirrhosis Complications or All-cause Mortality by Baseline Conn Score

up to 24 Weeks (Day 170)-ITT Population

# of
# of
Censored

Subjects
Events
<Week 24
Week 24¹
p-value²

Conn Score: 0

Overall Treatment

Comparison³

Any Rifaximin SSD
260
34
20 (7.7%)
206 (79.2%)
0.8915

Treatment

(13.1%)

Placebo
57
7 (12.3%)
6 (10.5%)
44 (77.2%)

Pairwise Comparisons

(versus Placebo)³

Treatment A: Rifaximin SSD
48
7 (14.6%)
3 (6.3%)
38
0.7477

40 mg qhs (IR Tablet)

(79.2%)

Treatment B: Rifaximin
55
11
7 (12.7%)
37
0.2297

SSD 80 mg qhs (IR Tablet)

(20.0%)

(67.3%)

Treatment C: Rifaximin
53
4 (7.5%)
5 (9.4%)
44
0.4007

SSD 40 mg qhs (SER Tablet)

(83.0%)

Treatment D: Rifaximin
48
1 (2.1%)
4 (8.3%)
43
0.0460

SSD 80 mg qhs (SER Tablet)

(89.6%)

Treatment E: Rifaximin
56
11
1 (1.8%)
44
0.3340

SSD 80 mg qhs (IR Tablet)

(19.6%)

(78.6%)

and Rifaximin SSD 80 mg qhs

(SER Tablet)

Conn Score: 1

Overall Treatment

Comparison³

Any Rifaximin SSD
160
15 (9.4%)
11 (6.9%)
134
0.8251

Treatment

(83.8%)

Placebo
37
3 (8.1%)
5 (13.5%)
29

(78.4%)

Pairwise Comparisons

(versus Placebo)³

Treatment A: Rifaximin
30
0
2 (6.7%)
28
0.0941

SSD 40 mg qhs (IR Tablet)

(93.3%)

Treatment B: Rifaximin
36
4 (11.1%)
2 (5.6%)
30
0.7015

SSD 80 mg qhs (IR Tablet)

(83.3%)

Conn Score 1

Treatment C: Rifaximin
31
5 (16.1%)
2 (6.5%)
24
0.3467

SSD 40 mg qhs (SER Tablet)

(77.4%)

Treatment D: Rifaximin
39
2 (5.1%)
2 (5.1%)
35
0.5204

SSD 80 mg qhs (SER Tablet)

(89.7%)

Treatment E: Rifaximin
24
4 (16.7%)
3 (12.5%)
17
0.3075

SSD 80 mg qhs (IR Tablet)

(70.8%)

and Rifaximin SSD 80 mg qhs

(SER Tablet)

Conn Score: 2

Overall Treatment

Comparison³

Any Rifaximin SSD
2
1 (50.0%)
0
1 (50.0%)

Treatment

Pairwise Comparisons

(versus Placebo)³

Treatment D: Rifaximin
2
1 (50.0%)
0
1 (50.0%)

SSD 80 mg qhs (SER Tablet)

IR = immediate release;

ITT = intent to treat;

qhs = once daily at bedtime;

SER = sustained extended release;

SSD = solid soluble dispersion.

¹Number of subjects censored at Week 24 (subject did not experience an event and was enrolled in the study at Week 24).

²P-value was obtained using a stratified log-rank test.

³Stratified by analysis region (study centers are grouped within 2 regions, centers in the United States and centers in Russia)

Time since First Diagnosis of Liver Cirrhosis

The influence of a subject's time since first diagnosis of liver cirrhosis on the primary efficacy analysis was evaluated. The time since first diagnosis of liver cirrhosis subgroups were categorized as <947 days or ≥947 days. Table 7 presents the analysis of the primary efficacy endpoint by time since first diagnoses of liver cirrhosis. A near statistically significant difference in the time to hospitalization for any of the liver cirrhosis complications or all-cause mortality was observed within ≥947 days subgroup and, like the PP and baseline Conn score 0 populations, was in favor of the SER 80 mg qhs treatment group versus placebo (stratified log-rank p=0.0517). The overall treatment comparison effect for any of the rifaximin SSD treatment versus placebo was not statistically significant (time since first diagnosis of liver cirrhosis: <947 days stratified log-rank p=0.3961; time since first diagnosis of liver cirrhosis: ≥947 days stratified log-rank p=0.5689).

TABLE 7

Analysis of Primary Efficacy Endpoint: Time to Hospitalization for any of the

Liver Cirrhosis Complications or All-cause Mortality by Categorized Time Since First

Diagnosis of Liver Cirrhosis up to 24 Weeks (Day 170)-ITT Population

Weeks (Day 170)-ITT Population

Censored

# of Subjects
# of Events
<Week 24
Week 24¹
p-value²

<947 Days

Overall Treatment

Comparison³

Any Rifaximin SSD
206
32
14 (6.8%)
160
0.3961

Treatment

(15.5%)

(77.7%)

Placebo
50
5 (10.0%)
7 (14.0%)
38

(76.0%)

Pairwise Comparisons

(versus Placebo)³

Treatment A: Rifaximin
43
3 (7.0%)
3 (7.0%)
37
0.4929

SSD 40 mg qhs (IR Tablet)

(86.0%)

Treatment B: Rifaximin
41
8 (19.5%)
7 (17.1%)
26
0.2329

SSD 80 mg qhs (IR Tablet)

(63.4%)

Treatment C: Rifaximin
46
8 (17.4%)
2 (4.3%)
36
0.3436

SSD 40 mg qhs (SER

(78.3%)

Tablet)

Treatment D: Rifaximin
34
3 (8.8%)
1 (2.9%)
30
0.7582

SSD 80 mg qhs (SER

(88.2%)

Tablet)

Treatment E: Rifaximin
42
10
1 (2.4%)
31
0.1237

SSD 80 mg qhs (IR Tablet)

(23.8%)

(73.8%)

and Rifaximin SSD 80 mg

qhs (SER Tablet)

Censored

Censored

# of Subjects
# of Events

# of Subjects
# of Events

>947 Days

Overall Treatment

Comparison³

Any Rifaximin SSD
215
18 (8.4%)
16 (7.4%)
181
0.5689

Treatment

(84.2%)

Placebo
44
5 (11.4%)
4 (9.1%)
35

(79.5%)

Pairwise Comparisons

(versus Placebo)³

Treatment A: Rifaximin
34
4 (11.8%)
1 (2.9%)
29
0.9598

SSD 40 mg qhs (IR Tablet)

(85.3%)

Treatment B: Rifaximin
50
7 (14.0%)
2 (4.0%)
41
0.6094

SSD 80 mg qhs (IR Tablet)

(82.0%)

Treatment C: Rifaximin
38
1 (2.6%)
5 (13.2%)
32
0.1523

SSD 40 mg qhs (SER

(84.2%)

Tablet)

Treatment D: Rifaximin
55
1 (1.8%)
5 (9.1%)
49
0.0517

SSD 80 mg qhs (SER

(89.1%)

Tablet)

Treatment E: Rifaximin
38
5 (13.2%)
3 (7.9%)
30
0.8519

SSD 80 mg qhs (IR Tablet)

(78.9%)

and Rifaximin SSD 80 mg

qhs (SER Tablet)

IR = immediate release;

ITT = intent to treat;

qhs = once daily at bedtime;

SER = sustained extended release;

SSD = solid soluble dispersion.

¹Number of subjects censored at Week 24 (subject did not experience an event and was enrolled in the study at Week 24).

²P-value was obtained using a stratified log-rank test.

³Stratified by analysis region (study centers are grouped within 2 regions, centers in the United States and centers in Russia).

Time to Development of Medically Refractory Ascites up to Week 24 (Day 170)

Analysis of the time to development of medically refractory ascites up to Week 24 (Day 170) is presented in Table 8.

A statistically significant difference in time to development of medically refractory ascites up to 24 Week was observed in favor of the IR 40 mg qhs treatment group versus placebo (stratified log-rank p=0.0308) and in favor of the SER 40 mg qhs treatment group versus placebo (stratified log-rank p=0.0202). No other pairwise treatment comparisons versus placebo were statistically significant. The overall treatment comparison for any of the rifaximin SSD treatments versus placebo was not statistically significant.