Pfizer is calling on the FDA to retroactively assign four-letter suffixes to biologics that act as reference products for innovative biosimilars.

In a draft guidance released in March, the agency scrapped its original plan to apply the naming convention to older biologics and said it believes it’s unnecessary to change the proper names of biological products that have already been licensed or approved and that don’t have an FDA-assigned suffix.

But Pfizer says innovator biologics that serve as reference products for a biosimilar should retroactively receive a suffix, as the move has the potential to “increase the likelihood of awareness and utilization of the suffixes in adverse event reporting.”

“Experience with generic drugs shows that despite drastically reduced dispensing of branded drugs following entry of generic options to the marketplace, there is a substantial increase in adverse event reports being ascribed to the branded product,” said Laura McKinley, Pfizer’s director of regulatory policy. “This suggests that adverse events associated with the generic drug are being inappropriately attributed to the brand.”