If you have any symptoms you are concerned about you should talk to your neurologist office ASAP. This is not one of the drugs I have taken but if you use the little magnifying glass in the upper left you will see many discussions on this treatment by others in the group.
There is also a lot of information and sites that come up in a simple google search. In this one I don’t see multiple myeloma listed specifically but other side effects-
Your system likely works differently than ours in the US but I would need to start with my Neurologist and they would refer me to the Oncologist if there were symptoms that pointed towards multiple myeloma
There is also a support line for this drug https://www.gilenyahcp.com/gilenya-go-program
I actually see a post of “In a recent study published in the Journal of Experimental Medicine, researchers found that fingolimod (sold as Gilenya), an FDA-approved orally administered drug to treat multiple sclerosis, could reduce painful side effects of multiple myeloma treatments.”