Only its use in rheumatoid arthritis requires the concomitant use of methotrexate by the U.S. Food and Drug Administration (FDA) product labeling; however, the concomitant use of methotrexate in other disease states may help to reduce the bodys immune response to the infliximab and increase its duration of efficacy. Pharmacology
Infliximab is a purified, recombinant DNA-derived chimeric human-mouse IgG monoclonal antibody that consists of mouse heavy and light chain variable regions combined with human heavy and light chain constant regions. It has a serum half-life of 9.5 days and can be detected in serum 8 weeks after infusion treatment.Infliximab neutralizes the biological activity of TNF-α by binding with high affinity to the soluble (free floating in the blood) and transmembrane (located on the outer membranes of T cells and similar immune cells) forms of TNF-α, and inhibits or prevents the effective binding of TNF-α with its receptors. Infliximab and adalimumab (another TNF antagonist) are in the subclass of "anti-TNF antibodies" (they are in the form of naturally occurring antibodies), and are capable of neutralizing all forms (extracellular-, transmembrane-, and receptor-bound) of TNF-α. Etanercept, a third TNF antagonist, is in a different subclass (receptor-construct fusion protein), and, because of its modified form, cannot neutralize receptor-bound TNF-α. Additionally, the anti-TNF antibodies adalimumab and infliximab have the capability of lysing cells involved in the inflammatory process, whereas the receptor fusion protein apparently lacks this capability. Although the clinical significance of these differences have not been absolutely proven, etanercept, has been shown to perform worse than placebo for Crohns disease.
Although the US brand name is Inflectra, it is marketed in the European Union as Remsima.The FDA approved Samsung Bioepis Co., Ltd.s Renflexis (infliximab-abda) in April 2017.Biogen released another biosimilar, Flixabi, which was approved in Germany, the UK, and the Netherlands. Flixabi was approved for use in the European Union in May 2016.In December 2017, Ixifi (infliximab-qbtx) was approved in the United States.Zessly was approved for use in the European Union in May 2018.In December 2019, Avsola (infliximab-axxq) was approved in the United States.Avsola was approved for medical use in Canada in March 2020.In December 2021, Ixifi was approved for medical use in Canada. Availability/affordability
In the United States, infliximab is an expensive medication, costing about US$900 for a 100 mg dose, and is covered by almost every US medical insurance plan (though caps on many plans make it possible to be covered for only a subset of treatments in the course of a year). Infliximab is supplied as a sterile, white, lyophilized (freeze-dried) powder, so must be reconstituted and administered by a health care professional, usually in a hospital or office setting. For this reason, it is usually covered under major medical insurance rather than prescription drug coverage. The loading regimen for all approved indications occurs at weeks 0, 2, and 6 at the above dosages.In the UK, infliximab is available from the NHS for Crohns disease treatment provided three criteria are met.