Data from Chimerix's completed mouse ectromelia and
rabbitpox studies are intended to address the requirement under the FDA's Animal Efficacy Rule for two different animal models of efficacy.
Four pivotal trials in non-human primates (NHPs) and two pivotal trials in rabbits demonstrated that TPOXX significantly reduced both mortality and viral load in NHP infected with monkeypox virus (MPXV) and in rabbits infected with
rabbitpox virus.
BPSV, bovine papular stomatitis virus; CPXV, cowpox virus; RPXV,
rabbitpox virus; MPXV, monkeypox virus; ORFV, for virus; PCPXV, pseudocowpox virus; PVNZ, parapoxvirus of red deer in New Zealand; SPV, sealpox virus; VARV, variola virus.
(10) Their results have since been replicated, and methods have been improved to produce even deadlier strains of mousepox and
rabbitpox. In October 2003, New Scientist reported that the U.S.
American scientists deliberately engineered a new, extra-deadly form of mousepox that kills all mice, even those that have been vaccinated, and much the same result has been accomplished with cowpox and
rabbitpox. The new variety of
rabbitpox is not contagious, however, which could add to its value as a terrorist weapon if the disease were ever to cross the species barrier, because its application could be narrowly targeted.
Rabbitpox virus from Utrecht has a unique deletion of only 2 residues (254, 255); VACV-3737 and VACV-Malbran share a 5--amino acid deletion (245-249).