This is the end of many inflammatory diseases (3)
I believe the answer is:
tis
This clue is a double definition.
'this is' is the first definition.
('tis' can be a contraction of 'this is')
'the end of many inflammatory diseases' is the second definition.
(suffix in laryngitis, appendicitis etc)
(Other definitions for tis that I've seen before include "That thing's" , "It is shortened" , "I confirm the identity of" , "Sequel to "Angela's Ashes"" , "For poet, that's" .)