Real-World Evidence

Introduction

The data presented below were gathered in a retrospective, real-world cohort study. Real-world evidence (RWE) provides data that can supplement the randomized clinical trial (RCT) findings, which remain the gold standard for evaluating the efficacy and safety of a treatment. Interpretation of the results are at the discretion of the audience as RWE data have inherent limitations.

Real-world evidence of XIFAXAN use: 30-day & annual rehospitalization due to OHE2

Patient classification based on treatment in the 30-day post-discharge window

XIFAXAN use: 30-day & annual rehospitalization due to OHE desktop XIFAXAN use: 30-day & annual rehospitalization due to OHE mobile

Sample size and disposition

Commercially insured adults with an initial OHE hospitalization were identified and classified based on treatment received within a 30-day window after discharge and assessed for OHE rehospitalization and costs.

  • OHE patients with ≥1 hospitalization* (N=3304)
  • Adults 18-64 years old as of initial OHE hospitalization*, (N=3162)
  • Continuous health plan enrollment (N=2012)

Study design

Claims analysis from MarketScan® Commercial Subset (October 1, 2015, through March 31, 2020). Patients were identified and classified based on treatment received in the 30-day post-discharge period. In patients who received XIFAXAN (± lactulose) within 30 days (N=1452), 78.4% (n=1138) received treatment at discharge (no delay). In patients who did not receive XIFAXAN within 30 days (N=560), 60.2% (n=337) of patients received lactulose alone.

Inclusion criteria: Adults (18-64 years old) with an initial overt OHE hospitalization* and continuous health plan enrollment

Exclusion criteria: Patients who had a liver transplant on or before the discharge date of the first OHE hospitalization were excluded from this study.

*Due to the lack of an OHE-specific ICD-10 code at the time of the study period to identify an OHE hospitalization in claims data, medical expertise was used to operationalize the definition of OHE hospitalization.1

Also excluding patients who had a liver transplant on or before the discharge date of the first observed OHE hospitalization.

Continuous health plan enrollment ≥6 months prior to and ≥30 days after the first observed hospitalization.

Observed reduction in OHE-related rehospitalizations with XIFAXAN2

Compared with patients given XIFAXAN without delay, other treatment subgroups showed increased odds of 30-day
risk of OHE rehospitalization and increased incidence of annual OHE rehospitalization

Observed reduction in OHE-related rehospitalizations with XIFAXAN desktop Observed reduction in OHE-related rehospitalizations with XIFAXAN mobile

§Analyses were adjusted for a priori selected potential confounding factors associated with OHE hospitalization (ie, age, gender, health plan, region, cirrhosis-specific comorbidity scoring system score, prior gastroenterology consult, duration of index OHE hospitalization, treatment during baseline [eg, rifaximin, HE prophylaxis with antibiotics], indicators of portal hypertension [eg, varices], and factors associated with HE [eg, frailty index]).

Study limitations

Results are based on observational claims data and are considered to have relevant limitations:

  • Due to the retrospective design of the study, no causality can be established
  • Claims data from commercially insured populations may not be generalizable to all patients with cirrhosis in the US and can contain omissions in coded procedures, diagnoses, and pharmacy claims
  • Claims data contain limited clinical and laboratory information; as such, it was not possible to observe inpatient medications nor obtain patients’ cirrhosis severity (eg, MELD score, Child-Pugh grades)
  • Despite adjustments for baseline characteristics in overt OHE hospitalization, residual selection bias and confounding may have remained
  • Due to a lack of a specific ICD-10 diagnosis code for HE at the time the analyses were conducted, patients with HE were identified using an algorithm developed based on medical expert input
  • For the purposes of this study, adherence was assumed to have been complete
  • These real-world evidence study results are based on a retrospective cohort study of claims data with unequal group sizes. This imbalance may potentially affect the generalizability of the findings. The unbalanced number of patients per group may introduce biases

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Dr. Jesudian discuss the real-world evidence for XIFAXAN use

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IR, incidence rate; MELD, Model for End-Stage Liver Disease; OHE=overt hepatic encephalopathy.

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INDICATIONS

XIFAXAN® (rifaximin) 550 mg tablets are indicated for the reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults and for the treatment of irritable bowel syndrome with diarrhea (IBS-D) in adults.

XIFAXAN® (rifaximin) 550 mg tablets are indicated for the reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults.

IMPORTANT SAFETY INFORMATION

  • XIFAXAN is contraindicated in patients with a hypersensitivity to rifaximin, rifamycin antimicrobial agents, or any of the components in XIFAXAN. Hypersensitivity reactions have included exfoliative dermatitis, angioneurotic edema, and anaphylaxis.
  • Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including XIFAXAN, and may range in severity from mild diarrhea to fatal colitis. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.
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INDICATIONS

XIFAXAN® (rifaximin) 550 mg tablets are indicated for the reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults and for the treatment of irritable bowel syndrome with diarrhea (IBS-D) in adults.

IMPORTANT SAFETY INFORMATION

  • XIFAXAN is contraindicated in patients with a hypersensitivity to rifaximin, rifamycin antimicrobial agents, or any of the components in XIFAXAN. Hypersensitivity reactions have included exfoliative dermatitis, angioneurotic edema, and anaphylaxis.
  • Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including XIFAXAN, and may range in severity from mild diarrhea to fatal colitis. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.
  • There is an increased systemic exposure in patients with severe (Child-Pugh Class C) hepatic impairment. Caution should be exercised when administering XIFAXAN to these patients.
  • Caution should be exercised when concomitant use of XIFAXAN and P-glycoprotein (P-gp) and/or OATPs inhibitors is needed. Concomitant administration of cyclosporine, an inhibitor of P-gp and OATPs, significantly increased the systemic exposure of rifaximin. In patients with hepatic impairment, a potential additive effect of reduced metabolism and concomitant P-gp inhibitors may further increase the systemic exposure to rifaximin.
  • In clinical studies, the most common adverse reactions for XIFAXAN (alone or in combination with lactulose) were:
    HE (≥10%): Peripheral edema (17%), constipation (16%), nausea (15%), fatigue (14%), insomnia (14%), ascites (13%), dizziness (13%), urinary tract infection (12%), anemia (10%), and pruritus (10%)
    IBS-D (≥2%): Nausea (3%), ALT increased (2%)
  • INR changes have been reported in patients receiving rifaximin and warfarin concomitantly. Monitor INR and prothrombin time. Dose adjustment of warfarin may be required.
  • XIFAXAN may cause fetal harm. Advise pregnant women of the potential risk to a fetus.

To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Please click here for full Prescribing Information.

References: 1. Gyawali B, Parsad S, Feinberg BA, Nabhan C. Real-world evidence and randomized studies in the precision oncology era: the right balance. JCO Precis Oncol. 2017;1:1-5. doi:10.1200/PO.17.00132 2. Jesudian AB, Gagnon-Sanschagrin P, Heimanson Z, et al. Impact of rifaximin use following an initial overt hepatic encephalopathy hospitalization on rehospitalization and costs. J Med Econ. 2023;26(1):1169-1177. doi:10.1080/13696998.2023.2255074

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