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Marburg and Ravn Viruses Summary

December 21, 2019

Marburg and Ravn viruses cause a disease that’s
very similar to the Ebola virus disease. So, it’s a multi-systemic, multi-organ failure,
you do have hemorrhagic manifestations. The case fatality rates are very high, just
like Ebola. In some of the outbreaks in central Africa,
they’ve been up to 90% case fatality rates. At this point there are no FDA approved therapeutics
or vaccines for Marburg or Ravn virus. So doctors typically treat patients that are
infected with Marburg or Ravn virus through palliative care. Just like the Ebola patients in Emory where
you’d be in a critical care unit and they would be replacing electrolytes and replacing
fluids, providing pain relief, that type of thing. Because during an outbreak scenario, when
you have a patient come to your clinic or to the treatment unit, you’re not quite sure
exactly where they are in their disease course. They don’t come to a hospital until they’re
at a very critical stage of illness. So we would not begin treating an animal until
it had signs of illness. So we want to see how far into the disease
course we can intervene and still save the patient. And in these studies we can test where that’s
at and know when the therapy is actually going to be efficacious or not. I think the benefit here is that this is a
human, a fully human monoclonal antibody. So, unlike a lot of the other therapies this
is, there’s a lot known about monoclonal antibody therapy. It’s used for other infectious diseases, so
safety would be one benefit. And we had two groups of non-human primates,
or actually three groups of non-human primates, where one group received the antibody beginning
four days after exposure to Marburg virus, and they were completely protected. A second group received the antibody five
days after they were exposed to Marburg virus. 80% of those animals were protected. And then the final group was treated with
a monoclonal antibody five days after they were infected with Ravn virus and they were
completely protected. The antibody that was employed in this particular
project was made in plants. So one of the things that we’re looking at
is seeing if we can manufacture this antibody in mammalian. And, so, basically it’s a production issue
so that we can do it cheaper and make more of the antibody at a lower cost. And, so if you do that, is the antibody still
protective in primates? So, that’s one of the things that we’re looking
at. The other thing that we’re looking at is,
again, is can we optimize this, can we develop additional antibodies that maybe we can delay
treatment even further and even closer to the time of death and still protect humans
or non-human primates? So, we’re following up on these results to
see how much further can we push these out. The antibody is not the only therapy that
we have that work against Marburg and Ravn viruses. There are other ones that work very well and
we’re looking in to using these as combinations.

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