The U.S. FDA (Food and Drug Administration) has approved IXIFI (infliximab-qbtx) as a biosimilar to Remicade. IXIFI, manufactured by Pfizer, targets tumor necrosis factor in order to help reduce inflammation. IXIFI has the same indications as Remicade, including for use with methotrexate in individuals with moderate-to-severe rheumatoid arthritis. It is also indicated for use in individuals with Crohn’s Disease, Ulcerative Colitis, Ankylosing Spondylitis, Psoriatic Arthritis, and Plaque Psoriasis. Like Remicade, IXIFI is a chimeric human-murine monoclonal antibody (mAb), however, IXIFI is a biosimilar to Remicade, and is not an identical or generic form of the medication.1
Since biologic medications, like Remicade, are created from a complex mixture of living entities, small changes in the way they are made or manufactured can lead to a slightly different product. When a different manufacturer tries to create a medication that functions the same as an already available biologic from the same living components, they will undoubtedly create a slightly different product from the original. However, if studies can demonstrate that this highly similar product has no clinically meaningful differences from its reference product (the biological product that has already been approved and is currently manufactured), the FDA will deem it to be a biosimilar. Since there still are incredibly minor differences present, biosimilars cannot be called generics, as generics are created to be the exact same as their reference product.2
The FDA’s labeling of IXIFI as a biosimilar to Remicade came after reviewing evidence that demonstrated that IXIFI was highly similar to its reference product. The REFLECTIONS B537-02 clinical trial was a major source of this evidence. The REFLECTIONS B537-02 study was a Phase 3, randomized, multinational, double-blind, two-arm parallel group study. Its goal was to evaluate the safety, and efficacy of IXIFI versus Remicade, as well as to evaluate its immunogenicity (its ability to evoke an immune response).
The trial included adults with moderately to severely active RA. These individuals also had no response or an inadequate response to methotrexate. The primary efficacy endpoint of these studies was the proportion of those achieving a 20 percent reduction in a composite measure of disease activity. This measurement is called an ACR20, and is defined by the American College of Rheumatology (ACR). By week 14 of the trial, this endpoint was met, and data continued to support that this endpoint was still met at week 30.
There are three biosimilars to Remicade (made by Janssen) that have FDA approval. These include Inflectra (infliximab-dyyb, made by Celltrion/Pfizer), Renflexis (infliximab-abda, made by Samsung and Merck), and now IXIFI (infliximab-qbtx). As is the case with many immune system-affecting medications, individuals taking IXIFI be monitored for signs of serious infection while taking the medication. Individuals taking IXIFI should also be monitored for signs of hypersensitivity (allergic) reactions, as well as be tested for tuberculosis infection before starting the medication. The most common side effects of IXIFI are infections, such as pharyngitis (sore throat), sinus infections, and upper respiratory infections, as well as headache, abdominal pain, and infusion-related reactions.3
FDA Approves New Pfizer Biosimilar. Pfizer Inc. https://www.pfizer.com/news/press-release/press-release-detail/fda_approves_new_pfizer_biosimilar. Published December 13, 2017. Accessed December 16, 2017.
Biosimilar and Interchangeable Products. U.S. Food and Drug Administration. https://www.fda.gov/Drugs/DevelopmentApprovalProcess/HowDrugsareDevelopedandApproved/ApprovalApplications/TherapeuticBiologicApplications/Biosimilars/ucm580419.htm#biosimilar. Published October 23, 2017. Accessed December 16, 2017.
IXIFI Prescribing Information. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/761072s000lbl.pdf. Published December 2017. Accessed December 16, 2017.