Last month, the Food and Drug Administration approved the first biosimilar in the U.S.—Sandoz's Zarxio, a biosimilar version of Amgen's Neupogen (filgrastim). This effectively launches a new industry—one where lower-cost biosimilars will eventually create a competitive market. According to Express Scripts, biosimilars could help save billions per year in drug spending in the U.S. alone. While this FDA approval is welcome, key patient safety-issues remain, including how to name these products.
Because biosimilar medicines, like all biologics, are made from living cells (“large molecule drugs”), they cannot be exact copies of the “brand” product. Biosimilars are not the same as generic versions of traditional chemical compound products (“small molecule drugs”). This is a key point to understanding the naming issue. Generics have the exact same international nonproprietary name, or INN, as the original product. This same name helps doctors, pharmacists and insurers track all generics that may have had an adverse impact on patients.
But what if the drug in question is not the same as the original drug, as is the case for biosimilars? The answer is incredibly complicated. Even as the first biosimilar is approved, the FDA continues to wrestle with that question of distinguishable versus class names. In its approval of Zarxio, FDA chose the name “filgrastim-sndz”—providing the drug with a suffix to form a unique name.
However, the FDA has indicated that “filgrastim-sndz” is only a temporary answer, stating that it is an “interim” name and “should not be viewed as reflective of the agency's decision on a comprehensive naming policy for biosimilars and other biological products.” While this unique placeholder name is a step in the right direction, the FDA needs to formalize a position on naming, especially as more biosimilars come to market.
While biosimilars represent a significant opportunity to expand access for many patients to life-saving therapies, they are also highly complex drugs that come with a risk of immunogenicity, a negative immune response that can be fatal. Further, the FDA is expected to hold an advisory committee meeting in the coming weeks to evaluate a biosimilar application for the first monoclonal antibody (mAb), which involves a molecule many times larger than filgrastim, a relatively simple molecule that is naturally occurring in the body.
Sandoz has been marketing its filgrastim biosimilar in the Europe for many years without serious event. Many argue, therefore, that the nonproprietary naming system used in the EU for the past eight years suggest that “same names” can be used successfully. However, as noted above, filgrastim and essentially every other biosimilar being used in the EU to-date are first-generation, relatively simple biologic molecules. The second generation biosimilars, the mAbs, are just beginning to enter the EU market. In fact, Inflectra, the first such mAb, was just launched in major European markets in February 2015. Historical data that is collected from the first generation biologics will be largely irrelevant and will not provide an accurate picture of potential problems as complex second generation biologics—which are the vast majority of biologic medicines—enter the marketplace.
The success of the biosimilars market hinges on transparency and accountability. As a physician, I want to know that my patient will receive the exact drug I am prescribing. Should there be a problem, I want to know that the system will be able to trace it back to the manufacturer so that we can quickly address concerns.
In my practice, we regularly prescribe biologic medicines and they have been effective treatment options for my patients. Ensuring easily distinguishable names for all biologics and biosimilars reflects the scientific fact that they are different products from one another. Clarity resulting from distinguishable names will enable better safety monitoring of adverse events through good pharmacovigilance.
In addition, the FDA plans to release several other guidances in 2015, including one on labeling of biosimilar products and one on indication extrapolation. The latter involves the nature and number of clinical studies to demonstrate that the biosimilar can effectively treat all of the originator product's indications. In its future guidances, the FDA should require transparency and accountability to be paramount. Although the first biosimilar has now been approved, the agency still must still address several important questions. Here's to 2015—the year of the biosimilar; but as the new products arrive, let's shepherd them in the best possible way to support patient safety.
Dr. Bert Petersen is director of the Breast Surgery Clinic of St. Barnabas Hospital in the Bronx and adjunct associate professor of surgery at New York University School of Medicine.
