Summary
P-selectin inhibition has been evaluated as a therapeutic for prevention and treatment
of venous thrombosis. In this study, a novel oral small-molecule inhibitor of P-selectin,
PSI-421, was evaluated in a baboon model of stasis induced deep vein thrombosis (DVT).
Experimental groups included i) primates receiving a single oral dose of 1 mg/kg PSI-421
two days prior and continued six days after thrombosis (n=3); ii) primates receiving
a single daily subcutaneous dose of 0.57 mg/kg enoxaparin sodium two days prior and
continued six days post thrombosis (n=3); and iii) primates receiving no treatment
(n=3).PSI-421 treated primates had greater percent vein reopening and less vein wall
inflammation than the enoxaparin and controls at day 6. Microparticle tissue factor
activity (MPTFA) was significantly lower in the animals receiving PSI-421 immediately
after thrombosis (T+6 hours day 0) suggesting lower potential for thrombogenesis in
these animals. PSI-421 also reduced soluble P-selectin levels versus controls at T+6
hours day 0, day 2 and 6. Experimental animals in any group showed no adverse effects
on coagulation. This study is the first to demonstrate a reduction in MPTFA associated
with vein reopening and reduced vein inflammation due to oral P-selectin inhibition
in a baboon model of DVT.
Keywords
Venous thrombosis - small-molecule inhibitor of P-selectin - P-selectin - veins -
microparticle tissue-factor activity