Table 4.

Activity of selected compounds in vivo.

PR antagonist	Dose of full efficacy	Application route[a]
Termination of early pregnancy in rats (n=6)[b]
lonaprisan	0.5 mg kg−1	p.o.
compound 1	1.5 mg kg−1	p.o.
compound 11	0.5 mg kg−1	s.c.
compound 18 (vilaprisan)	0.5 mg kg−1	p.o.
compound 19	0.5 mg kg−1	p.o.
Endometrial transformation in rabbits (n=5)[c]
lonaprisan	1.0 mg kg−1	p.o.
compound 1	3.0 mg kg−1	p.o.
compound 11	1.0 mg kg−1	p.o.
compound 18 (vilaprisan)	1.0 mg kg−1	p.o.

[a] p.o.: per os; s.c.: subcutaneous. [b] Full efficacy in termination of early pregnancy studies means that all animals of the corresponding dose group lack implantations or have pathologic nidation sites. [c] Full inhibitory efficacy in endometrial transformations studies means that the degree of glandular differentiation in all animals of the corresponding dose group was characterized by a McPhail index of 1 or 1.5.