I don't think it would "delay the study" because of having to change the "trial protocol" filed "with the FDA". I say that because CT*X has been adding new clinical sites to its trials after the trials began. (And the stated purpose was to accelerate the trial to completion.) As to adding additional researchers; even if they will need more researchers, they still have over two years left on the trial. I think they have time to hire additional staff if necessary.
At the projected enrollment rate with only one site, they will only average a little over one patient per week. Since patients who are waiting on this treatment are dying every day; that two and a half year timeline seems almost criminal. I hope they speed things up...