The companies behind biologic drugs argue that the branded drugs and their generic versions, dubbed biosimilars, are not interchangeable. But a new study suggests otherwise, at least for a class of biologics called TNF-α inhibitors, which are used to treat a number of diseases.
Unlike drugs, which are created by combining chemical components, biologics are synthesized in a living system, such as plant or animal cells. Even small changes in the manufacturing process can result in a drug that is structured differently and works differently, and there has been variation between batches of the same drug produced at the same facility, according to a statement. For this reason, it is impossible to create an identical copy of a biologic. Insulin, for example, is a biologic, and so are many cancer drugs and vaccines.
Researchers from the Johns Hopkins Bloomberg School of Public Health and Brigham and Women’s Hospital compared 19 studies using original and biosimilar versions of TNF-α (tumor necrosis factor alpha) inhibitors to treat rheumatoid arthritis, psoriasis and irritable bowel disease. This class of drug blocks TNF, a signaling protein involved in inflammation that is associated with autoimmune disease.
The studies included 8 Phase I trials, 5 Phase II trials and 6 observational studies. The researchers found that “available data suggests that biosimilar drugs have very similar safety and effectiveness as their branded counterparts,” according to the statement. However, the team highlighted some limitations, including the small sample size in some studies, possible publication bias and the lack of published studies for some biosimilars.
Despite these caveats, the study comes at a time where many biologics are coming off patent, or have already done so. The only FDA-approved TNF inhibitor is infliximab, marketed as Remicade, by Johnson & Johnson ($JNJ) in the U.S. and China, Mitsubishi Tanabe in Japan and Merck ($MRK) elsewhere. It has already come off patent and the FDA approved Celltrion and Pfizer’s ($PFE) Remicade copy earlier this year.
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