Are coagulation times biomarkers? Data from a phase I study of the oral thrombin inhibitor LB-30057 (CI-1028)

Pharmacokinetic-Pharmacodynamic Analysis' Role in Design of Phase ⅠClinical Trials of Anticoagulant Agents: A Systematic Review

INTRODUCTION

There remains an unmet need for better anticoagulants. The phase I clinical trial is of great significance in the development of anticoagulants, and the design is special. This system review aims to provide insights for the design of future phase I clinical trials of anticoagulants.

AREAS COVERED

We searched the database PubMed and ClinicalTrail.gov website, to collate the phase I clinical trial of anticoagulants in healthy people. The study protocol, inclusion-exclusion criteria, safety, and pharmacodynamic indexes were reviewed.

EXPERT OPINION

New anticoagulants under development focused on inhibiting one or more than one serine proteases within the coagulation cascade. Agents targeting intrinsic factors are in the pipeline of the drug development. The enrollment eligibility criteria have more restrictions on laboratory tests, medical history, or medication history related to bleeding and coagulation; more precautions were taken to assess and minimize the risk of hemorrhagic events. Pharmacodynamics markers were evaluated as a surrogate marker of anticoagulation potency to guide further dose selection in drug's development. In future, the positive control study can be applied in phase I studies of new anticoagulants with appropriate pharmacodynamics markers, which can provide more favorable information on making 'go/no' decision in drug development.

Pharmacokinetic/pharmacodynamic relationships for otamixaban, a direct factor Xa inhibitor, in healthy subjects

Direct pharmacokinetic/pharmacodynamic relationships for otamixaban were investigated after rising doses in healthy subjects using mixed-effect modeling. Activated partial thromboplastin time, prothrombin time, dilute prothrombin time, and Russell's viper venom-induced clotting time (RVVT) related linearly, whereas Heptest clotting time (HCT) followed a sigmoidal E(max) model. The pharmacokinetic/pharmacodynamic response (slope) and their corresponding interindividual variability (seconds per ng/mL, [% coefficient of variation]) were 0.263 (29%) for Russell's viper venom-induced clotting time, 0.117 (10%) for dilute prothrombin time, 0.058 (19%) for activated partial thromboplastin time, and 0.021 (11%) for prothrombin time. For Heptest clotting time, the parameter estimates with their corresponding interindividual variability (% coefficient of variation) were 71 ng/mL (30%) for EC(50), 186 seconds (64%) for E(max), and 17 seconds (16%) for E(0). The model predicted otamixaban plasma concentrations to double the clotting times that were close to those observed. These pharmacokinetic/pharmacodynamic relationships, together with the predictable pharmacokinetics, allowed the anticoagulant effect at given doses of otamixaban to be foreseen in healthy subjects.