by Amanda Conschafter, blog editor
The Food and Drug Administration approved the second U.S. biosimilar on Tuesday, clearing the drug for seven different indications. Infliximab-dyyb is administered via infusion for the treatment of rheumatoid arthritis, Crohn’s disease and ulcerative colitis, among other conditions. Though the FDA has not yet released final guidance on naming biosimilar medications, its approval of biosimilar infliximab seems to forecast the agency’s decision. The drug carries a randomly generated suffix to distinguish it from its biological innovator product.
The random-suffix system mimics the approach taken earlier this year by the World Health Organization – but belies worries from physicians and patient advocates that random names will complicate decision-making and pharmacovigilance.
In a letter to the FDA, the Alliance for Patient Access explained that “FDA’s proposed naming rule would be more useful to prescribers if the qualifier incorporated meaningful letters and/or numbers that identity each product with its manufacturer.” That way, AfPA noted, “physicians, pharmacists, and patients would more easily memorize and recognize these codes and the medications they identify.”
The FDA has at different points in time endorsed both random and memorable suffix systems.
[Read: The Biosimilar Naming Dilemma]
Indication Extrapolation and Patient Safety
Biosimilar infliximab’s approved indications include uses for which it has not undergone comprehensive clinical trials. Transferring approved uses from the complex innovator drug to the biosimilar infliximab, a practice known as “indication extrapolation,” leaves some physicians and patient advocates uneasy. Biological drugs treat vastly different disease states and patient groups, some of which carry a higher risk of an immune system response. Approving medical therapies to treat these diseases without full testing may exacerbate the risks.
Europe and Canada, where infliximab biosimilars are already on the market, have differed in their willingness to tolerate these risks. The European Medicines Agency granted full extrapolation for biosimilar infliximab, while Health Canada declined to extrapolate an approved use for inflammatory bowel diseases. Canadian regulators cited concerns about the clinical impact of structural differences between the biologic and the follow-on biosimilar.
The FDA has applied full extrapolation for biosimilar infliximab. And in keeping with its recent draft guidance on labeling, the prescribing information for biosimilar infliximab provides clinical testing data from the innovator product, not the biosimilar itself.
Of the infliximab biosimilar’s approval, FDA’s Janet Woodcock, MD, said in a statement that, “Patients and the health care community can be confident that biosimilar products are high quality and meet the agency’s rigorous scientific standards.” Meanwhile, leadership from the innovator company notedthat the approval did not suggest interchangeability between the biosimilar and the biologic. Johnson & Johnson’s Chief Biotechnology Officer Jay Siegel explained that interchangeability required “a manufacturer [to] demonstrate that the biosimilar is expected to produce the same clinical result as the reference product in any given patient” and to demonstrate that “the risk of alternating or switching between the reference product and biosimilar is no greater than the risk of using the reference product.”