Haemorragic fever from the Ebola virus is fatal in up to 80%of cases in humans. The virus is thought to cause excessive blood coagulation and thrombosis leading to organ dysfunction. Inhibition of the blood coagulation pathway could therefore be a potential therapeutic approach for ebola treatment.
Thomas W Geisbert from the US Army Medical Research Institute of Infectious Diseases and colleagues injected 12 rhesus macaques with the ebola virus to induce the deadly ebola haemorragic fever. Nine of the macaques received an inhibitor of the blood coagulation pathway (called recombinant nematode anticoagulant protein c2, rNAPc2), while three macaques received the ebola virus only (the control group).
Treatment with rNAPc2 prolonged survival time and resulted in a 33% survival rate; this contrasted with macaques in the control group, of whom all except one died (since the study was completed the remaining control animal has also died). The surviving macaques in the treatment group were in good health nine months after the study. Survival was longer (12 days) for treated macaques who died compared with untreated macaques in the control group (8 days).
Thomas W Geisbert comments: "Our results have great clinical implications, since our treatment approach of Ebola haemorrhagic fever targets the disease process rather than replication of the infectious agent. Moreover, our findings raise the possibility that rNAPc2 could be useful in the treatment of other viral haemorrhagic fevers. Importantly, rNAPc2 has a suitable phamacokinetic and safety profile in human beings. The clinical efficacy of this treatment modality now needs to be proven."