23 years old Multiple sclerosis (MS) patient for about 10 years, is medication necessary?

My girlfriend is 23 years old and has been a MS patient for about 10 years. Her first MS attack happened when she was 14. It was in her right eye. The second one happened when she was 20 and it was in her left eye. After the second attack she was prescribed to inject a drug called CinnoVex which Iranian version similar to Avonex. You can find information about CinnoVex in the link below.

She used CinnoVex until recently. But the injections are painful and with some minor side effects. Then a few month ago she had an MRI and based on that there was no sign of MS plaques in her brain. But her doctor says that it is better for her to continue her medication as a preventive measure. The doctor has changed her drug to another one which is called Cinnumer. This one is just made in Iran and you can see its information in this link.

The question that I have is: should she take this medication even though she is ok at the moment? Some other doctor’s here say that it is not necessary, but her own doctor which is very famous in MS field believe that she needs to be under medication for the rest of her life. We are kind of confused and would appreciate some expert opinion to help us make the best decision in this situation. Thank you all and sorry for my bad English.