I very much believe that PLX-R18 for ARS will not need human safety studies.
Looking deeper into the matter there is an extra key item that lead me to this conclusion.
This being that I noticed on the Pluristem Corporate presentation - January 2017, that I mentioned before, that after the two expected ARS timeline events of:
- Data readout dose selection studies ARS - H1/2017
- Contract with U.S. government for ARS – H2/2017
there is another expected milestone immediately after which I didn't fully appreciate before which is:
- Initiation of pivotal study ARS NHP - H2/2017
It's the 'NHP' bit that threw me off originally however now I know this to mean Non-Human Primate. Having looked into ARS research on NHP this mean that, based on the research I've just read regards NHP in ARS they will use Macaque Rhesus Monkeys, for the final Pivotal stage.
So going on my understanding that I do not think the US gov nor Pluristem would go this far and then at the end to do safety data in humans and have it all fall apart, would be due to the following.
We know the current imminent data is a dose selection study. This requires testing the product in various animal models deemed to react similarly to how the pathophysiology might work in humans, to arrive at a does that would make sense for a human. And these large animal models (dog for example) might be easier to get approval for testing with regards ethical issues. As we all know, generally speaking, mice are the easiest and monkeys are among the hardest to get approval for.
Then after the treatment has been shown to work positively in multiple large animal models and a dosage can be identified (the ethically easier part). Then we go for the pivotal trial by performing the final test in an 'NHP' model.
In the final stage, the 'NHP' model could serve as both safety and efficacy without human testing. This due to the fact that Macaque Rhesus monkeys (the most commonly used NHP in research and has been specifically used in ARS research) are 93% genetically the same as humans. And the physiology of these monkeys has been well documented, thus the pathophysiology would be relatively straightforwards to analyse, with comparison to humans.
I admit this theory is not as 'good' as doing the safety in humans, but this is the only way I can see this making sense. Otherwise indeed, we would need to wait for specific R18 human safety data. Or then again maybe Allo is right and we're somehow missing something and thinking too much.
All said though, with my above theory and that I still feel strongly on the premise that they (US gov & Pluristem) could not have gone this far just to have it fall flat in their faces when they could have done safety studies back in 2015 when the NIAID was initially going with Pluristem to the FDA, would, I feel, honestly be ridiculous.
Thoughts?
