Singapore Drugs Database

Indication

* Indicated for reducing signs and symptoms and inducing and maintaining clinical remission in adult or pediatric (≥ 6 years of age) patients with moderately to severely active **Crohn’s disease** who have had an inadequate response to conventional therapy * Indicated for reducing the number of draining enterocutaneous and rectovaginal fistulas and maintaining fistula closure in adult patients with fistulizing **Crohn’s disease**. * Indicated for reducing signs and symptoms, inducing and maintaining clinical remission and mucosal healing, and eliminating corticosteroid use in adult or pediatric (≥ 6 years of age) patients with moderately to severely active **ulcerative colitis** who have had an inadequate response to conventional therapy. * Indicated for, in combination with methotrexate, reducing signs and symptoms, inhibiting the progression of structural damage, and improving physical function in patients with moderately to severely active **rheumatoid arthritis**. * Indicated for reducing signs and symptoms in patients with active **ankylosing spondylitis**. * Indicated for reducing signs and symptoms of active arthritis, inhibiting the progression of structural damage, and improving physical function in patients with **psoriatic arthritis**. * Indicated for the treatment of adult patients with chronic severe (i.e., extensive and/or disabling) **plaque psoriasis** who are candidates for systemic therapy and when other systemic therapies are medically less appropriate.

Mechanism of Action

Infliximab is a IgG1κ monoclonal antibody that binds to soluble and transmembrane forms of TNF-α with high affinity to disrupt the pro-inflammatory cascade signalling. Binding of the antibody to TNF-α prevents TNF-α from interacting with its receptors. Infliximab does not neutralize TNF-α (lymphotoxin-α), a related cytokine that utilizes the same receptors as TNF-α [FDA Label]. Blocked actions of TNF-α further leads to downregulation of local and systemic pro-inflammatory cytokines (i.e. IL-1, IL-6), reduction of lymphocyte and leukocyte migration to sites of inflammation, induction of apoptosis of TNF-producing cells (i.e. activated monocytes and T lymphocytes), increased levels of nuclear factor-κB inhibitor, and reduction of reduction of endothelial adhesion molecules and acute phase proteins [A31469]. Its inhibitory actions on TNF-α was demonstrated in human fibroblasts, endothelial cells, neutrophils, B and Tlymphocytes and epithelial cells [FDA Label]. Infliximab also atteunates the production of tissue degrading enzymes synthesized by synoviocytes and/or chondrocytes. According to a transgenic mice study that developed polyarthritis due to consitutive levels of human TNF-α, infliximab decreased synovitis and joint erosions in collagen-induced arthritis and allows eroded joints to heal [FDA Label].

Pharmacokinetics

Absorption

Following a single intravenous infusion, infliximab absorption displays a linear relationship between the dose administered and the maximum serum concentration [FDA Label]. In patients with Crohn's disease, the maximum plasma concentration (Cmax) of infliximab following single doses of 5 mg/kg and 10 mg/kg was 75 µg/mL and 181 µg/mL, respectively. In a maintenance therapy study, multiple infusions of infliximab (at week 0, 2 and 6) at the same dose of 5 mg/kg and 10 mg/kg resulted in Cmax of 120 µg/mL and 189 µg/mL , respectively [A31469]. In patients with rheumatoid arthritis, the Cmax of infliximab following a single dose infusion of 5 mg/kg, 10 mg/kg and 20 mg/kg were 192±51 µg/mL, 427±106 µg/mL, and 907±183 µg/mL, respectively [A31469].

Distribution

Based on a pharmacokinetic study of adult patients, the distribution at steady state was independent of dose and indicated that infliximab was distributed primarily within the vascular compartment [FDA Label]. In patients with Crohn's disease, the apparent volume of distribution at steady state (Vss) of infliximab following single doses of 5 mg/kg and 10 mg/kg was 80 mL/kg and 65 mL/kg, respectively. In a maintenance therapy study, multiple infusions of infliximab (at week 0, 2 and 6) at the same dose of 5 mg/kg and 10 mg/kg resulted in Vss of 70 mL/kg and 81 mL/kg , respectively [A31469]. In patients with rheumatoid arthritis, the Vss of infliximab following a single dose infusion of 5 mg/kg, 10 mg/kg and 20 mg/kg were 4.3±2.5 L, 3.2±0.7 L, and 3.1±0.6 L, respectively [A31469].

Metabolism

Elimination

Clearance

In patients with Crohn's disease, the total body clearance (CL) of infliximab following single doses of 5 mg/kg and 10 mg/kg was 18.4 mL/h and 14.3 mL/h, respectively. In a maintenance therapy study, multiple infusions of infliximab (at week 0, 2 and 6) at the same dose of 5 mg/kg and 10 mg/kg resulted in CL of 15.2 mL/h and 15.2 mL/h, respectively [A31469]. In patients with rheumatoid arthritis, the CL of infliximab following a single dose infusion of 5 mg/kg, 10 mg/kg and 20 mg/kg were 11±7.5 mL/h, 11.4±5 mL/h, and 11±8.9 mL/h, respectively [A31469]. Development of antibodies to infliximab increased infliximab clearance [FDA Label].

Toxicity

In an acute toxicity animal study, the NOAEL of intravenous infliximab in rats was 50 mg/kg. In a repeated dose animal study, the NOAEL values of intravenous infliximab was 50 mg/kg in rats at 2 weeks following 3 doses and 40 mg/kg/day in mice at 6 months [ MSDS]. The toxicological potential of infliximab in humans has not yet been fully established. According to an analogous antibody study, infliximab is not predicted to induce tumorigenic, clastogenic or mutagenic effects. No impairment of fertility was observed in a fertility and general reproduction toxicity study with the analogous mouse antibody used in the 6-month chronic toxicity study [FDA Label].

Active Ingredient/Synonyms

Infliximab (genetical recombination) | Infliximab-abda | Infliximab-dyyb | Infliximab-qbtx | Infliximab |