Biologics have revolutionised healthcare for some conditions - but have been expensive because of the multistep manufacturing processes required to create these complex molecules.
Changes to the manufacturing of biological agents make them more affordable, but can lead to drugs with different components from the original medicine tested in clinical trials, challenging assumptions about safety.
David Hunt, honorary consultant neurologist and Wellcome Trust intermediate clinical fellow, at the University of Edinburgh, joins us to describe how that happens and what the result can be.
Read the full analysis:
http://www.bmj.com/content/357/bmj.j1707
