Infliximab is a monoclonal antibody that is administered intravenously to treat a number of chronic inflammatory conditions.
Evolution of infliximab therapy – John K. Marshall, MD
Mechanism of action
Infliximab works by blocking the functional activity of a cell-signaling protein (cytokine) called tumor necrosis factor alpha (TNF-α), which is a substance that plays a key role in inflammation. Using infliximab to inhibit TNF-α does not cure the inflammatory disease; however, it reduces the signs and symptoms of inflammation that arise in patients with such conditions.
Also known by the brand name Remicade, infliximab first received approval from the United States Food and Drug Administration (FDA) in August 1998 for the treatment of Crohn’s disease. In 2004, this approval by the FDA was extended to rheumatoid arthritis and, in 2005, to ulcerative colitis (UC). Infliximab also received approval for the treatment of pediatric Crohn’s disease in 2006 and pediatric UC in 2011.
Active Crohn's disease failing to respond to therapy
Infliximab is currently approved in the United Kingdom for the treatment of patients with severe and active Crohn’s disease that has failed to respond to a full course of treatment with a corticosteroid and/or immunosuppressant. This treatment is also available for those who are intolerant to these therapies or have medical contraindications for them.
For these patients, infliximab is administered by intravenous infusion at a dosage of 5 milligrams (mg) per kilograms (kg) of body weight (5mg/kg) over a period of two hours. This is followed by a repeat infusion two weeks later. If symptoms do not improve after these two doses, no further treatment is administered.
In cases where the disease does respond to infliximab, patients receive maintenance treatments of 5 mg/kg infusions 6 weeks after the first dose, with infusions then following every 8 weeks. For adults, dose escalation may be an option if the disease stops responding.
Active fistulizing Crohn's
Patients with active and fistulizing Crohn’s disease that has failed to respond to a full course of conventional therapies such as drainage, antibiotics, and an immunosuppressant, can also be prescribed infliximab in the United Kingdom.
For these patients, infliximab is infused at a dose of 5 mg/kg for 2 hours with repeat infusions two and six weeks later. In cases where the disease fails to respond after these three doses, no further infliximab infusions are given.
For those with a disease that does respond to infliximab treatment, maintenance infusions of 5 mg/kg may be given every eight weeks or a re-administration treatment of 5 mg/kg may be given when symptoms recur, followed by the same infusion every 8 weeks. For adults, dose escalation may be considered if their disease has stopped responding.
Severe and active Crohn's in the pediatric population
Infliximab can also be used to treat patients between the ages of 6 and 17 years with severe and active Crohn’s disease that has failed to respond to conventional therapies including primary nutrition therapy, an immunomodulatory drug and a corticosteroid, or those who are intolerant or have medical contraindications for these therapies.
For these patients, intravenous infusions of 5 mg/kg are given followed by repeat infusions two and six weeks later, and then every 8 weeks.
The cost of a 100 mg vial of infliximab in the United Kingdom is £419.62, excluding VAT, and $987.56 in the United States.
Since the dose is adjusted according to a person’s body weight, the cost of treatment varies between individuals. The cost for someone weighing 73 kg, for example, would be £1,678 in the United Kingdom and $3,950.24 in the United States, because four 100 mg vials would be needed to administer a dose of 365 mg. With an assumed administration cost per infusion of £258 and $617, the cost of two infusions would be around £3,872 or $9,107. To continue therapy at the standard dose over a total of twelve months, the cost would be around £12,584 or $29,643.