|Prefix||Target substem||Source substem||Suffix|
|-ki(n)-||-k(i)-||interleukin as target||-u-||human|
|-le(s)-||—||inflammatory lesions||-xi-||chimeric (human/foreign)|
|-ne(u)(r)-||-n(e)-*||nervous system||-axo-||rat/mouse hybrid
(see trifunctional antibody)
|-toxa-||-tox(a)-||toxin as target|
|* under discussion as of February 2010|
The nomenclature of monoclonal antibodies is a naming scheme for assigning generic, or nonproprietary, names to a group of medicines called monoclonal antibodies. This scheme is used for both the World Health Organization’s International Nonproprietary Names and the United States Adopted Names. In general, suffixes are used to identify a class of medicines; all monoclonal antibody pharmaceuticals end with the suffix -mab. However, different preceding affixes are used depending on the structure and function of the medicine. These are officially called substems and sometimes erroneously infixes, but are actually suffixes as well.
The substem preceding the -mab suffix denotes the animal origin of the antibodies. The original monoclonal antibodies were produced in mice (-o-) or other non-human organisms, and these antibodies are recognized as foreign by the human immune system and may be rapidly cleared, provoke an allergic reaction, or both. To avoid this, parts of the antibody may be replaced with human sequences. If the constant region is replaced with the human form, it is termed chimeric and the substem used is -xi-. Part of the variable regions, typically everything but the complementarity determining regions, may also be substituted, in which case it is termed humanized and -zu- is used. Pure human antibodies use -u-.
The substem preceding the source of the antibody refers to medicine's target. In the naming scheme as originally developed, these substems mostly consist of a consonant, vowel, then another consonant. For ease of pronunciation and to avoid awkwardness, the final consonant may be dropped if the following source substem begins with a consonant (such as -zu- or -xi-). Examples of these include -ci(r)- for the circulatory system, -li(m)- for the immune system (lim stands for lymphocyte) and -ne(r)- or -neu(r)- for the nervous system.
In 2009, new and shorter target substems were introduced. They mostly consist of a consonant, plus a vowel which is omitted if the source substem begins with a consonant. For example, human antibodies targeting the immune system will receive names ending in -lumab instead of the old -limumab. Some endings, like -ciximab for chimeric antibodies targeting the circulatory system, will remain unchanged.
The prefix carries no special meaning and should be unique for each medicine.
A second word may be added if there is another substance attached or linked. If the antibody contains a radioisotope, the name of the isotope precedes the name of the antibody.