Antithrombotic effect of LB-30057 (CI-1028), a new synthetic thrombin inhibitor, in a rabbit model of thrombosis: comparison with inogatran.
LB-30057 (CI-1028) is a novel, orally bioavailable, direct thrombin inhibitor with a Ki of 0.38 nM against human thrombin. The effects of LB-30057 on thrombus formation and hemostasis were evaluated in a veno-venous shunt model of thrombosis in rabbits, and compared with inogatran, another direct inhibitor of thrombin. Each compound was studied at 5 or 6 different doses with 5 or 6 rabbits in each group. After administration as a bolus i.v. injection followed by continuous infusion, both LB-30057 and inogatran dose-dependently inhibited thrombus formation, which was measured as an increase in time to occlusion (TTO) and a decrease in thrombus weight. Both compounds also improved vena caval blood flow and reduced the overall incidence of thrombotic occlusion. LB-30057 significantly prolonged TTO from 23 +/- 4 min (before dose) to 110 +/- 10 min at the highest dose (0.7 mg/kg + 47 microg/kg/min) (p < 0.001), and reduced thrombus weight from 57 +/- 2 mg to 15 +/- 5 mg (p < 0.001). Occlusive thrombus formed in only one of six rabbits that received the highest dose of LB-30057 (vs. 13/13 in the control group, p < 0.01). At the dose that produced the maximum antithrombotic effect (0.7 mg/kg + 47 microg/kg/min), LB-30057 increased aPTT and bleeding time approximately 2-and 2.5-fold above baseline, respectively. On a gravimetric basis, LB-30057 and inogatran displayed comparable in vivo antithrombotic efficacy. When compared to equally effective anti thrombotic doses of inogatran, LB-30057 caused less prolongation in aPTT, had no effect on PT, and tended to have less of effect on bleeding time. These results indicate that LB-30057 is an effective antithrombotic compound and it appears to have a better benefit/risk profile than inogatran in this experimental model.
Cardiovascular Therapeutics Section, Parke-Davis Pharmaceutical Research Division, Warner Lambert Company, Ann Arbor, Michigan 48105, USA. Liguo.Chi@wl.com
L
L
Chi
T E
TE
Mertz
K L
KL
Rogers
N
N
Janiczek
Y W
YW
Peng
L
L
Saganek
R F
RF
Bousley
P L
PL
Juneau
A C
AC
Uprichard
K P
KP
Gallagher
D000818:Animals; D001549:Benzamides / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D001760:Bleeding Time; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005343:Fibrinolytic Agents / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006487:Hemostasis / Q000187:drug effects; D020007:Implants, Experimental; D007267:Injections; D010880:Piperidines / Q000494:pharmacology; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D013917:Thrombin / Q000037:antagonists & inhibitors*; D013927:Thrombosis / Q000188:drug therapy* / Q000517:prevention & control; D014683:Vena Cava, Superior
D001549:Benzamides; D005343:Fibrinolytic Agents; C116605:LB 30057; D010880:Piperidines; C099871:inogatran; D013917:Thrombin; D005998:Glycine