Cariboy72
Wow - great news.
I think maybe some others might be able to address a couple of your concerns.
As always, if you do a bit of google searches for the meds and the trial and look at reputable sources (medical journals, hospital reports, etc.) and avoid social media type input (facebook, instagram, etc.) you will find a lot of info that is easily digestible.
Being involved in research is excellent because many things will be covered by the study. Be sure to speak openly with the research nurse whom you will become intimate with -their role is as a patient advocate (as are all the medical staff, but nurses roles are very patient focused).
There will be lots of info in the PCRC that your partner will be required to sign in order to be involved in the study. Look at the side effect closely - there will be three different levels listed (mild, moderate, and sever), as well as some statement about what actions the doctor is able to do to mitigate the side effects. I did not pay close enough attention to this detail when I started in on the BCG study I was involved with, and suffered with side-effects longer than I should have (my own fault).
Have faith in the science and the fact that the doctors are all there to help/heal your partner.
I know my local hospital has a whole host of support measures for cancer patients (nutrition, spiritual, psychological, social, holistic, etc.) get the doc to provide the referrals early and check them out - if you don't need them currently at least you will have the knowledge and already be on the record for these services.
Don't stop asking questions and seeking support - as with this pandemic YOU ARE NOT ALONE
Ciao