The US Food and Drug Administration’s (FDA) Purple Book for biosimilars needs some modifications and new information to be more useful, pharmaceutical companies told FDA in recent comments.
According to FDA, the Purple Book
includes the date a biosimilar or biologic was licensed and whether FDA evaluated the biological product for reference product exclusivity. It also includes whether a biological product has been determined by FDA to be biosimilar to or interchangeable with a reference product.
But drugmakers are pushing back on this limited scope.
As Takeda notes: “More than 97 percent of products listed in the Purple Book that are eligible for exclusivity have no exclusivity determination.” And as of August, FDA’s Center for Drug Evaluation and Research (CDER) and the Center for Biologics Evaluation and Research (CBER) have listed first-licensure and exclusivity end dates for just five products.
“The absence of exclusivity information in the Purple Book is inconsistent with FDA's prior commitments,” Takeda said. “Moreover, the lack of an administrative record creates uncertainty about the exclusivity decisions FDA has made.” Mylan similarly called for FDA to make exclusivity determinations at the time of approval and publish those in the Purple Book.
As far as other additions to the Purple Book, Roche’s Genentech recommends the inclusion of approved indications for each biosimilar listed. “Without reference to the approved indication(s) for the licensed biological product, there could be the implication that a listed biosimilar for that product is approved for all of the same conditions of use in the reference product labeling,” Genentech said.
The Association for Accessible Medicines also calls for FDA to update the Purple Book to clarify which products have been determined not to have exclusivity (“e.g., those where any exclusivity period would have expired, if it applied in the first place”) and those that are still subject to pending decisions.
Biocon, meanwhile, suggests FDA develop product-specific monographs for reference products and include them in the Purple Book.
But Boehringer Ingelheim cautions that additions to the Purple Book may try to undermine “the proven safety, efficacy, and quality of all FDA‐licensed biosimilars.”
One such example comes from J&J’s Janssen, which is currently in a legal fight with Pfizer
over blocking Remicade biosimilars, said it wants to add the following language to the Purple Book with regard to interchangeable designations: “FDA has not made such a determination about a product approved as a biosimilar; pharmacy-level substitution is not advised and may be illegal under state law. In addition, FDA does not make such determinations regarding switching between two or more biosimilar products, whether interchangeable or not, and often there are little or no data regarding such switches.”
But Momenta Pharmaceuticals counters this argument about switching between biosimilars, saying, “If there can be a switch from the original reference product to a drifted reference product without proof of interchangeability, then there is no basis for denying a substitution of an interchangeable biologic for another interchangeable biologic.”