Immunomedics and Janssen sign marketing agreement

FDA rejects sacituzumab govetecan for CMC issues

https://www.immunomedics.com/our-company/news-and-events/immunomedics-announces-promotion-agreement-with-janssen-for-erdafitinib-in-the-u-s/

Janssen has just received approval for their erdafitinib molecule (BALVERSA) for the treatment of metastatic urothelial carcinoma.  Meanwhile, Immunomedics sacituzumab govetecan (IMMU-132) is targeting the same type of cancer and has been showing promise in the clinic:
https://www.onclive.com/conference-coverage/gu-2019/sacituzumab-govitecan-active-in-advanced-urothelial-carcinoma

However, the approval of IMMU-132 has been held up by the FDA:
https://bit.ly/2UNZjPx

So in the meantime, Immunomedics is partnering with Jannsen to promote their product with the agreement that the partnership will end upon the approval of IMMU-132 where they will become a competitor.

Is this a great opportunity for Immunomedics to salvage some of the US marketing machinery that they were building for the IMMU-132 rollout?  Or is this going to undercut their marketshare by promoting a competitor?
What do you think?