I think manufacturing remains a concern even if they're not using the same companies, the characteristics of the antibody may come into play as well. It's too early to actually be concerned given that we might still be at least a month out from the trial results, but I don't think the personnel for managing large scale manufacturing are in place yet.
IMMU was using their own Morris Plains facility, planning to transition to Samsung biologics in 2020 for the antibody. Johnson Matthey was to manufacture the drug-linker, and conjugation etc. was to be done at BSP Pharma. Page 15
https://www.immunomedics.com/wp-content/uploads/2019/01/JPM-January-2019.pdf
Enyedy mentioned their manufacturers during their JPM roadshow, I seem to remember Boehringer Ingelheim for the mab and don't remember the rest.