Portola Pharmaceuticals Inc. announced enrollment of subjects in the second cohort of its Phase 1 study of PRT4445, the first universal Factor Xa inhibitor antidote in clinical development. PRT4445 is a recombinant biologic designed to reverse the anticoagulant activity of oral and injectable Factor Xa inhibitors in patients suffering life-threatening bleeds or requiring urgent surgery. No agents are approved to specifically reverse the activity of oral Factor Xa inhibitors. Current strategies for mitigating serious bleeding in patients taking Factor Xa inhibitors include the administration of coagulation factors such as recombinant Factor VIIa or blood-derived prothombin complex concentrates, which have not been shown to be effective and are known to have prothrombotic risk.
PRT4445 is a companion product to betrixaban, a novel, oral, once-daily Factor Xa inhibitor. Portola is evaluating betrixaban in its global, pivotal Phase 3 APEX Study to show superiority to the current standard of care for hospital and post-discharge prevention of venous thromboembolism (VTE) in acute medically ill patients, a multi-billion dollar indication for which there are no approved therapies for use post hospital discharge.
”Factor Xa inhibitors have been shown to be a major advancement over current standard therapies, such as warfarin and enoxaparin. However, for patients taking these agents who are bleeding or require urgent surgery, physicians need a rapid reversal agent to return patients to normal hemostasis. Our goal is to bring to market the first antidote for both oral and injectable Factor Xa inhibitors to reverse their anticoagulant activity, when needed, and reduce the risk of life-threatening bleeds and associated costs,” said Michael M. Kitt, M.D., senior vice president and chief medical officer of Portola. “With the initiation of our Factor Xa inhibitor antidote clinical program and the Phase 3 study of betrixaban earlier this year, Portola now has in clinical development two unique hospital-based drugs in the field of thrombosis with the potential to establish a new standard of care.”
The Phase 1 single ascending dose safety and tolerability study of PRT4445 will include approximately 40 healthy volunteers and will be conducted in the United States. It will be followed this fall by a clinical proof-of-concept study to demonstrate the safety of PRT4445 and its ability to reverse the anticoagulation activity of Factor Xa inhibitors at steady state in subjects taking one of multiple Factor Xa inhibitors.
Date: June 15, 2012
Source: Portola Pharmaceuticals Inc.
Filed Under: Drug Discovery