Today, Tekmira disclosed that an acceptable regulatory
pathway has been found with US and Canadian regulators to use its RNAi Therapeutic against
Ebola infection, TKM-EBOLA, in the current outbreak. In fact, the company added that 'TKM-Ebola, has been administered to patients on an emergency basis and the repeat infusions have been well-tolerated'.
While not going into specifics, it is more or less a
confirmation that Dr Sacra who was said to have received multiple courses of a
treatment was indeed treated with TKM-EBOLA (he seems to have pulled through).
Further substantiating that suspicion was a comment by a relative that subsequent administrations of the experimental drug were better
tolerated:
'He also tolerated the research drug well – better than he had the previous doses he was given.”'
This is consistent with infusion
reactions of many intravenously administered drugs being a particular problem during the first
administration only.
Then there was another report that a number of suspected,
early cases had been evacuated from Western Africa to the US with the intention
of giving them experimental treatments.
This, in fact, would be the ideal setting for using TKM-EBOLA, or for
that matter most other experimental treatments against Ebola.
It should be remembered that while in the preclinical monkey studies,
the efficacy of TKM-EBOLA started to wane if treatment was delayed for more
than 3 days following infection of the animal, this experimental setting is more akin to a needle
stick accident in the lab given the large amount of virus involved in the innoculum.
By contrast, in the current outbreak in Western Africa, not
every contact obviously leads to a successful transmission of the virus, a reflection of
the fact that the starting viral population will be much less compared to the experimental setting. This means that it would take the virus more than 3 days to overwhelm the capacity of TKM-EBOLA and
the immune system to stall the infection in its tracks. Hopefully, Tekmira is conducting analogous innoculum-window-of-opportunity studies in monkeys to get a better sense of how much treatment can be delayed when infectious doses are quite low.
With this in mind, I am more or less convinced
that RNAi Therapeutics is saving patient lives for the first time. I personally would risk an anaphylactic shock
in a closely supervised clinical setting any day over the prospect of not getting
specific treatment when infected with Ebola. #RNAiHistory
