This sounds ethically questionable to me. I wouldn't rule it out entirely, but I'd want to see a well-reasoned argument, both technical and moral, that it was likely to lead to greatly reduced suffering for patients. Even then.... growing a body without a brain likely would not produce a model organism with predictive ability for human diseases.

I don't think the biology is there, let alone consensus on the major ethical questions involved

> human bodies without a brain for testing

I think the way a drug impacts the brain is kind of important

Can you imagine the political/religious push-back were you to do that?!

Growth of single human organs or organ tissue is easier, cheaper and less fraught with political peril.

We have the next best thing: organoids.

A more practical option is using brain-dead humans for medical testing. This was discussed recently in the journal Science, using the term "physiologically maintained deceased". As they say, this "traverses complex ethical and moral terrain". (I've seen enough zombie movies to know how this ends up :-)

https://www.science.org/doi/10.1126/science.adt3527

The anti abortion and anti birth control contingent would never let even a little of that happen in countries with significant fundamentalist and Catholic voters. There are plenty of examples where these people force babies to be born without a brain on principle. Just recently https://www.nbcnews.com/news/us-news/louisiana-woman-carryin... One can go back to something like Terri Schiavo https://en.wikipedia.org/wiki/Terri_Schiavo_case