The harmonization of World Health Organization International Nonproprietary Names definitions for cell and cell-based gene therapy substances: when a name is not enough.

The World Health Organization (WHO) assigns International Nonproprietary Names (INN) to pharmaceutical substances, including advanced therapy medicinal products, to ensure that each substance is globally recognized by a unique name. The majority of INN are published in the WHO Drug Information in accordance with the nomenclature rules of the International Union of Pure and Applied Chemistry. However, advanced therapy medicinal products, and in particular cell therapy and cell-based gene therapy substances, cannot be defined by such chemical nomenclature.