IXIFI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for IXIFI (IXIFI).
IXIFI (infliximab-qbtx) is a chimeric monoclonal antibody that binds with high affinity to soluble and transmembrane forms of tumor necrosis factor-alpha (TNF-α), thereby neutralizing its pro-inflammatory activity and blocking TNF-α receptor binding.
| Metabolism | Infliximab-qbtx is a monoclonal antibody; metabolism is primarily via catabolism by the reticuloendothelial system, not by hepatic cytochrome P450 enzymes. |
| Excretion | Infliximab (IXIFI) is primarily eliminated via the reticuloendothelial system and proteolytic degradation. Renal excretion is negligible (<0.1%). No significant biliary or fecal excretion of intact drug occurs. Metabolism is not hepatic but via target-mediated clearance and nonspecific proteolysis. |
| Half-life | Terminal elimination half-life is approximately 7.7-9.5 days (range 7-12 days). Clinical context: Supports every-8-week dosing intervals; shorter half-life may be seen in patients with higher tumor burden or immunogenicity (anti-drug antibodies). |
| Protein binding | Infliximab is a monoclonal antibody; plasma protein binding is negligible (<1%). It circulates as free antibody, not bound to albumin or other proteins. |
| Volume of Distribution | Volume of distribution is approximately 3.0-4.5 L (0.04-0.06 L/kg), indicating limited extravascular distribution, primarily confined to the vascular space. Clinical meaning: Low Vd confirms that infliximab does not extensively penetrate tissues; high concentrations are maintained in plasma. |
| Bioavailability | Intravenous administration yields 100% bioavailability; intramuscular or subcutaneous routes are not approved due to lack of data and potential immunogenicity. No oral bioavailability. |
| Onset of Action | IV administration: Clinical improvement (e.g., reduction in Crohn's Disease Activity Index) can be seen within 2 weeks, with maximal effect often by 6 weeks. The onset is more rapid than adalimumab due to higher initial doses. |
| Duration of Action | Duration of clinical effect is approximately 8 weeks following a 5 mg/kg IV infusion. Some patients may require dose escalation or interval shortening to 6 weeks due to loss of response. Levels above 3-7 mcg/mL are associated with sustained efficacy. |
5 mg/kg intravenously at 0, 2, and 6 weeks, then every 8 weeks thereafter.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required based on GFR. |
| Liver impairment | No dose adjustment required for Child-Pugh A or B; use with caution in Child-Pugh C due to limited data. |
| Pediatric use | For children ≥6 years: 5 mg/kg intravenously at 0, 2, and 6 weeks, then every 8 weeks; weight-based dosing. |
| Geriatric use | No specific dose adjustment; monitor for infections and infusion reactions due to age-related decline in immune function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for IXIFI (IXIFI).
| Breastfeeding | Infliximab is excreted into breast milk in small amounts. The milk-to-plasma ratio (M/P) is approximately 0.01–0.05. Oral bioavailability of infliximab in infants is low due to gastrointestinal degradation. Current evidence suggests that breastfeeding during infliximab therapy is considered acceptable, as systemic exposure to the infant is minimal. However, infants should be monitored for potential adverse effects, such as infections. |
| Teratogenic Risk | Infliximab (IXIFI) is a monoclonal antibody (IgG1) that crosses the placenta, with increasing transfer during the second and third trimesters. First trimester exposure is associated with limited data but no clear pattern of major malformations. Second and third trimester exposure may result in detectable serum levels in the infant at birth, potentially increasing the risk of infections. Limited evidence suggests a possible association with preterm birth and low birth weight, but no consistent teratogenic effect has been documented. |
■ FDA Black Box Warning
Serious infections (including tuberculosis, bacterial sepsis, invasive fungal infections) leading to hospitalization or death; increased risk of lymphoma and other malignancies (especially hepatosplenic T-cell lymphoma in adolescents/young adults with Crohn's disease and ulcerative colitis).
| Serious Effects |
["Moderate to severe heart failure (NYHA class III/IV)","History of hypersensitivity to infliximab or murine proteins","Active, serious infection (including sepsis, abscesses, TB, opportunistic infections)","Concomitant use with live vaccines"]
| Precautions | ["Serious infections (reactivation of latent infections, including TB)","Hepatitis B reactivation","Hepatotoxicity (rare, severe)","Hematologic abnormalities (pancytopenia)","Hypersensitivity reactions (including anaphylaxis)","Neurologic events (demyelinating disease, seizures)","Heart failure exacerbation","Lupus-like syndrome","Malignancy risk (especially in pediatric patients)","Live vaccines avoid"] |
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| Fetal Monitoring | Maternal monitoring: Regular assessment of disease activity and signs of infection. Fetal monitoring: Ultrasound assessment of fetal growth and development if exposure occurs during second or third trimester. Neonatal monitoring: Infants exposed in utero should be monitored for infections and live vaccines should be avoided for at least 6 months after birth due to potential immunosuppression. |
| Fertility Effects | Infliximab does not appear to impair fertility in men or women. In animal studies, no adverse effects on male or female fertility were observed. In humans, no significant changes in fertility have been reported, but underlying inflammatory disease may affect fertility, and treatment may improve fertility by controlling disease activity. |