And a long history of not becoming wide spread. From TFA "Russell said he and his team had engineered the virus to make it more suitable for cancer therapy." I just assumed the term "suitable" really meant "profitable" but some of the comments indicate it was modified to target the cancer better (how so?). It seems the cost of trials and approvals is too high for a naturally occurring virus, so everyone wants to customize them so they become patentable.
The naturally occurring virus would not treat MM. There is real R&D going on here to make this work as an MM treatment.
From the paper: "Unlike naturally occurring measles, MV-Edm, and hence MV-NIS, targets CD46 as a cell-entry and cell fusion receptor. CD46 is a ubiquitous complement regulatory protein that, fortuitously, is highly expressed on human myeloma cells, making them abnormally susceptible to MV-NIS infection, syncytium formation, and cell killing."
So they tweaked the virus to target CD46 which MM cells express way above normal. The MM cells are therefore significantly more susceptible to being killed by the virus.
https://en.wikipedia.org/wiki/Oncolytic_virus