I hope you weren’t’ trying to trivialise this important study,...

I hope you weren’t’ trying to trivialise this important study, but I am afraid you did with your protein bar analogy.

A better analogy is
1) Using a sample of people with an incurable disease, and possibly only months to live, give them a small dose of a trial drug with the main aim to only test how tolerable that dose is and the effectiveness of two delivery mechanisms.
2) To then notice that no recipients have any adverse reactions and in fact 75% of recipients had a temporary stay of execution of a disease that usually does not take a rest.
3) Now increase the dose by a few orders of magnitude, to further test tolerability and now, following the results of the first cohort, also to look at any further abatement of the disease.
4) The aim is to find the max, or most effective, tolerable dose to then take to a golden standard double blind study.

But in this case, the double blind study may be difficult as standard care involves brain surgery! I truly hope, for humane reasons, that the final trial is open label. This should be acceptable because CAR-T therapy has already been proven in studies by other companies. Tolerability should be the main, and almost only, real goal.