GTC Biotherapeutics (fka GTCB)

[DewDiligence]

Is FVIII+FVIIa combination therapy a good idea?
This study finds markers to help answer the question.

http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=HistorySearch&query_key=1&WebEnv=0dYeE_7nv20qdt...

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Preclinical Toxicity Biomarkers for Combination Treatment with rFXIII and rFVIIa

Biomarkers. 2007 Jul-Aug;12(4):424-44

Oleksiewicz MB, Schaal-Jensen R, Kiehr B, Krabbe JS, Sommer C.

Novo Nordisk A/S, Maalov, Denmark.

Combination treatment with the clotting factors recombinant activated factor VII (rFVIIa), serine protease, and recombinant factor XIII (rFXIII), protransglutaminase, is being explored for haemostatic therapy. We performed a single-dose toxicology study in the cynomolgus monkey, with four dose groups receiving 0.1 + 0.34 mg kg(-1) (group 1), 0.33 + 1.12 mg kg(-1) (group 2), 1.67 + 5.60 mg kg(-1) (group 3) and 5.00 + 16.80 mg kg(-1) (group 4) of a rFVIIa + rFXIII combination.

In the three lower dose groups, no clinical, histopathological or blood chemistry changes were observed. In group 4, the animals died at 4 h post-dosing, with histopathology revealing a systemic coagulopathy resembling, but distinct from, disseminated intravascular coagulation. Due to the absence of toxicity warning signs, toxicity biomarkers were identified by a Western blot-based screening of approximately 20 plasma proteins known to be involved in the clotting cascade.

Three of the examined proteins were specifically affected by rFVIIa + rFXIII treatment. Fibronectin and fibrinogen exhibited dose-dependent reductions from less than 10% reduction (group 2) to more than 90% reduction (group 4). These reductions were reversible, and specific. For vitronectin, a dose-dependent conversion to the 65-kDa form was found to occur in groups 3 and 4. Thus, fibrinogen, fibronectin and vitronectin represent the first biomarkers for clotting factor toxicity.
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