Mod-5014, a Novel Long-Acting FVIIa Proposing An Improved Prophylactic and On Demand Treatment For Hemophilic Patients Following SC and IV Administration – Comprehensive In -Vitro and In -Vivo evaluation In Preparation For Clinical Studies
Authors: Hart Gili , Hershkovitz Oren , Iilan Ahuva Bar , Zakar Miri , Binder Lior , Fima Eyal 
Published: October 2019

Abstract

Introduction
Prolor Biotech Inc. is a clinical stage public company developing biobetter long acting versions of existing therapeutic proteins utilizing a technology termed CTP. The technology involves fusion of the C terminus peptide of hCG to one or both ends of the target protein. The technology was clinically validated and proven as a safe and efficient way for prolonging the half-lives of several therapeutic proteins while maintaining their biological activity. The aim of this extensive study was to characterize the in vitro potency as well as the in –vitro interactions of MOD-5014 (FVIIa-CTP ) with physiological inhibitors and cofactors and to determine its pharmacokinetic (PK), pharmacodynamic (PD) and long term hemostatic effects in the relevant hemophilic animal models following IV and SC administrations as moving forward into clinical studies .

Methods
FVII-CTP was expressed in CHO cells, purified and activated utilizing a CTP specific purification process. MOD-5014 interactions with physiological inhibitors and cofactors was characterized in –vitro utilizing SPR and ex-vivo assays ( TEG and TG). In order to assess the long term in vivo effect , MOD-5014 was administered to warfarin treated rats or FVIII-/- mice, and following IV and SC injection the PK and PD profiles were determined as well as coagulation parameters (PT,aPTT ,TG and FVIIa activity) at a time dependent manner. In addition, the long term hemostatic effect was evaluated following bleeding challenge by tail clip assay and tail vein transection as compared to commercial rFVIIa.

Results
MOD-5014 in vitro activity was comparable to commercial FVIIa. PT , thrombin generation , PK and PD parameters following IV and SC administration were superior to those of rFVIIa. PT values of warfarin treated rats were maintained normal for significantly longer time post injection. MOD-5014 half-life and AUC following IV administration were 5 and 3.5 fold higher, respectively and were also significantly superior following SC injection. Following SC administration, MOD-5014's bioavailability, was shown to be superior to commercial rFVIIa in both rats and hemophilic mice models as well. In a tail vein transection studies, MOD-5014 had a profound effect on survival rate, which was maintained for more than 24 and significantly reduced duration and intensity of bleeding was also observed in tail clip studies in warfarin treated rats as well as in hemophilic mice in both routes. Finally, toxicological studies in rodents demonstrated that MOD-5014 is safe and tolerable at relatively high doses.

Conclusion
Attachments of CTP to FVIIa led to a markedly enhanced PK, increased exposure as reflected by AUC, improved recovery and a prolonged hemostatic effect in hemophilic mice and rats further supporting the comparable specific activity of MOD-5014 to rFVIIa. In addition, SC administration of MOD-5014 resulted in improved bioavailability and exposure was significantly prolonged relative to IV administration which was also translated to superior-vivo efficacy. CTP attachment to FVIIa had no significant impact on the in-vitro interactions with physiological inhibitors and cofactors proposing a similar mechanism of action and comparable activity.
Our data suggest that CTP fused FVIIa is safe and tolerable in rodents and has the potential to significantly the frequency of injection given on demand as well as potentially enable prophylactic treatment for hemophilic patients.

Disclosures:
No relevant conflicts of interest to declare.