Table II.

A summary of small molecule inhibitors targeting E1s, E2s and E3s.

Drug	Target	Company	Status
PYR-41	E1	Millennium Pharmaceuticals, Inc. (Cambridge, MA, USA)	N/A
MLN4924	E1	Millennium Pharmaceuticals, Inc. (Cambridge, MA, USA)	Phase II
CC0651	E2	N/A	N/A
NSC697923	E2	N/A	N/A
Nutlin	E3	Roche Products Limited (Pharmaceuticals) (Welwyn Garden City, UK)	Phase I
MI-773	E3	Sanofi S.A. (Gentilly, France)	Phase I
CGM097	E3	Novartis International AG (Basel, Switzerland)	Phase I

N/A, not applicable.