The people with SPMS under discussion here who safely stopped taking DMTs seem to have been 70 years old or older. From PubMed, March 1, 2017:
Int J MS Care. 2017 Jan-Feb;19(1):11-14.
Stopping Disease-Modifying Therapy in Nonrelapsing Multiple Sclerosis: Experience from a Clinical Practice
Birnbaum G.
BACKGROUND:
Current disease-modifying therapies (DMTs) are of benefit only in people with relapsing forms of multiple sclerosis (RMS). Thus, safely stopping DMTs in people with secondary progressive MS may be possible.
METHODS:
Two groups of patients with MS were studied. Group A consisted of 77 patients with secondary progressive MS and no evidence of acute central nervous system inflammation for 2 to 20 years. These patients were advised to stop DMTs. Group B consisted of 17 individuals with RMS who stopped DMTs on their own. Both groups were evaluated at treatment cessation and for a minimum of 1 year thereafter. Multiple variables were assessed to determine those that predicted recurrent acute disease.
RESULTS:
Nine patients in group A (11.7%) and ten patients in group B (58.8%) had recurrent acute disease, almost always within 1 to 2 years of stopping treatment. The only variable of significance in group A distinguishing stable and relapsing patients was age (P = .0003), with relapsing patients being younger. Group B patients were younger and had significantly lower Expanded Disability Status Scale scores than group A, with no significant differences in age between relapsed and stable patients.
CONCLUSIONS:
The DMTs can be stopped safely in older patients with MS (≥7 decades) with no evidence of acute disease for 2 years or longer, with an almost 90% probability of remaining free of acute recurrence. The high proportion of untreated patients with RMS experiencing recurrent acute disease is consistent with published data.