Abstract
Vatreptacog alfa is a genetically engineered variant of recombinant factor VIIa (rFVIIa)
containing three amino acid changes. Aspartic acid, valine, and glutamine residues
replace valine, glutamic acid, and methionine at positions 158, 296, and 298, respectively.
These substitutions result in considerable enhancement of the intrinsic (tissue factor-independent)
capability to activate factor X and the downstream hemostatic events are consequently
augmented. The beneficial effects of vatreptacog alfa have been demonstrated in numerous
in vitro systems attempting to mimic hemophilia and corroborated in in vivo models.
Vatreptacog alfa has successfully passed through phase 1 and 2 clinical trials and
the molecule is currently being explored in phase 3 clinical trial for the treatment
of bleedings in hemophilia patients with inhibitors. This article describes the proposed
mechanism behind the increased activity and action of vatreptacog alfa and reviews
available data, which suggest that vatreptacog alfa could be a valuable addition to
the existing portfolio of treatment options for hemophilia patients with inhibitors.
Keywords
vatreptacog alfa - factor VIIa variant - intrinsic activity - factor X activation
- tissue factor-independent capability