Monoclonal Antibodies: How to Navigate the Naming Scheme

Monoclonal antibodies are named based on a specific structure developed by the International Nonproprietary Names Working Group, under the direction of the World Health Organization. This structure consists of a prefix, substem A, substem B, and suffix.

The prefix does not follow any specific criteria, except that it must distinguish an antibody from other products.  Substem A specifies the target of the antibody, such as a tumor or bacterial target, while substem B specifies the sequence from which the monoclonal antibody was derived, so antibodies that were derived from a mouse would contain the substem -o-. The suffix –mab is a common stem for all monoclonal antibodies.

The common stem indicates that the product contains an immunoglobulin-binding domain that binds to a defined target region.8 A list of the substems A and B and their respective targets or origins are available in the following table:

This naming scheme may seem complicated, but it actually provides a lot of information about the monoclonal antibody. Looking at rituximab, for example, the suffix -mab indicates that it is a monoclonal antibody, the substem -xi- denotes that it is of chimeric origin, the substem –tu- shows that it targets a tumor, and the prefix ri- is its individualized prefix.

While monoclonal antibodies have vast therapeutic potential, there are some limitations to their use. First, the production cost is incredibly high for a few reasons, including that fact that large amounts of antibody are needed to invoke the proper response and ample purification must occur in order to comply with Good Manufacturing Practice conditions.