Table 6.

Table 6a In vivo metaphase analysis of rat bone marrow cells from male animals dosed with Pfizer MEK1 inhibitor
Agent	Dose (mg/kg)	% Mitotic index	% Cells with chromosomal aberrations (±S.D.)
Vehicle control	–a	5.9	0.0
MEK1	0.3	4.5	0.6 (0.4)
	1.0	6.7	0.6 (0.4)
	3.0	4.2	2.6 (7.0)
Cyclophosphamide (positive control)	60.0	0.9	62.4b (5.15)

Table 6b In vivo metaphase analysis of rat bone marrow cells from female animals dosed with Pfizer MEK1 inhibitor
Agent	Dose (mg/kg)	% Mitotic index	% Cells with chromosomal aberrations (±S.D.)
Vehicle control	–a	7.2	0.2 (0.2)
MEK1	0.3	6.7	0.2 (0.2)
	1.0	7.6	0.4 (0.24)
	3.0	3.6	1.0 (0.77)
Cyclophosphamide (positive control)	60.0	1.0	89.8b (4.8)

Doses were administered to groups of five Sprague–Dawley rats once daily for 2 days (except for the positive control which was administered only once, 24 h before bone marrow harvest) by oral gavage and the bone marrow harvested 24 h after the final dose.

^a0.5% methylcellulose/0.2% Tween 80 in water.

^bStatistically significant, p < 0.05.