What is the future of targeted therapy in rheumatology: biologics or small molecules?

Table 1 Key characteristics of biologics versus small molecules

	Biologics	Small molecules
Chemical composition	Protein	Organic small molecule
Structure	Known sequence, variable three-dimensional structure and glycosylation	Well-defined structure
Molecular weight	>1 kDa	<700 Da
Stability	Protease and heat-sensitive	Mostly stable
Administration	Parenteral	Oral
In vivo half-life	(Usually) Long	(Usually) Short
Target	Extracellular	Intracellular
Mechanism of action	(Usually) Blocking, depletion	(Usually) Enzyme inhibition
Specificity	High	Low/variable
Manufacturing cost	High	Low/variable
Degradation	Catabolism	Metabolism
Generics	Biosimilar	Identical

The table highlights selected typical key characterisitics of biologic therapeutics and small-molecule anti-rheumatic agents. Specific drugs may deviate from the typical features. Further differences, such as costs and standards of manufacturing, regulatory requirements, registration path, supply chain logistics, and so on have been omitted.

ISSN: 1741-7015