Objective To evaluate the contribution of MRI activity and relapses in defining disease activity in Secondary progressive multiple sclerosis (SPMS) patients by analysing real-world data from Adelphi real-world MS Disease Specific Programme (Adelphi-MS-DSP) and to understand whether active SPMS (aSPMS) and non-active SPMC (naSPMS) are mutually exclusive groups in EXPAND.

Methods Adelphi-MS-DSP was a non-interventional, multinational real-world study (N=37,318). Patients were categorised into aSPMS (⩾1 new lesion on the most recent MRI and/or ⩾1 relapse in the last 12-months) and naSPMS groups. In EXPAND, disease activity was defined as relapses in the 2-years before screening and with/without ⩾1 gadolinium-enhancing (Gd+) T1 lesion at baseline. Demographics, MRI and relapse status were analysed descriptively.

Results SPMS from the Adelphi-MS-DSP were categorised as aSPMS (n=1889) and naSPMS (n=665). Disease activity for aSPMS was based on MRI lesions (59.1%), relapses (12.6%), and both (28.3%). In EXPAND, 52.6% of patients (n/N=866/1645) who had no relapse in the 2-years prior to screening and no Gd+ T1 lesions at baseline were categorised under naSPMS; of these who were on placebo, 52.7% experienced on-study relapse and/or MRI activity.

Conclusions In both real-world and clinical studies, MRI activity appears to be a more sensitive measure of disease activity versus relapses. Funding: Novartis Pharma AG, Basel, Switzerland.