In the end, it comes down to the level of monitoring required for a particular treatment, where the patient is in his or her life, and where he or she is in the disease course.
What are some potential complications when switching therapies?
When switching therapies, one of the bigger concerns is how quickly can we get the patient on the new therapy. Some medications when stopped can lead to return of disease activity or possibly lead to a rebound phenomenon with significant inflammatory activity. We focus on transitioning a patient quickly to a new drug that has a rapid mechanism of action thus limiting the amount of time that a patient is without a treatment. However, based on the mechanism of action of the drug you must consider if a wash out is necessary. The question is how quickly can the patient start the new drug thus preventing a rebound phenomenon. Ideally, no wash out would protect the patient best but might have safety concerns depending on the switch drug profile. If the switch was related to concerns for high JC virus antibody titer going off of natalizumab, there may be a need to make sure the patient does not have PML before making the switch. This may require MRIs and CSF analysis prior to switching.
Ultimately, we consider whether the drug we are switching the patient to is going to be more efficacious than the drug that the patient was previously on. We consider the safety and side effect profile of the new medication. We balance the risk of the disease with the risk of the medication. We must factor in the patient’s tolerance for risk as well and make the best decision with all the available factors considered.