MRI more sensitive for disease activity than relapses in SPMS

In both real-world and clinical trial setting, MRI activity is a more sensitive tool to measure disease activity than relapses in secondary progressive MS.

Disease activity was more commonly detected via MRI than relapse

Patients with SPMS are often categorised as active (aSPMS) or non-active (naSPMS) based on evidence of their disease activity, explained Prof. Gavin Giovannoni (Queen Mary University of London, UK). However, the relative contribution of MRI-activity and/or relapses in defining disease activity is not well understood. Therefore, differences between aSPMS and naSPMS were evaluated.

Data were used from the Adelphi real-world MS Disease Specific Programme (Adelphi MS DSP), and the phase 3 EXPAND study. Adelphi MS DSP is a non-interventional real-world study of 37,318 MS patients, including 3,580 patients with SPMS who were surveyed between 2011 and 2019. This group was categorised into aSPMS (≥1 new lesion on the most recent MRI and/or ≥1 relapse in the last 12 months; n=1889) and naSPMS (n=665).

In the 1651 participants of the EXPAND study, aSPMS was defined as ≥1 relapses in the 2 years prior to screening and/or ≥1 gadolinium-enhancing (Gd+) T1 lesion at baseline. According to this definition, 779 patients had aSPMS and 866 naSPMS. “In patients from the real-world cohort categorised as having aSPMS, disease activity was more commonly detected via MRI than relapse activity”, Prof Dr Giovannoni observed.

52.7% of naSPMS patients on placebo had on-study relapse

They were considered aSPMS based on relapse status alone (12.6%), on MRI status alone (59.1%), or on both MRI and relapse status (28.3%). In the past 12 months, naSPMS patients had a higher mean EDSS score versus aSPMS patients (4.6 and 5.2, respectively), were less frequently monitored with MRI (58.7% vs 87.7%), and had a lower number of MRIs per patient (0.87 vs 1.24). A higher proportion of naSPMS patients had moderate-to-severe disease, and were not on any DMT (45.1% vs 23.4%).

In EXPAND, 52.7% of naSPMS patients on placebo had on-study relapse and/or MRI activity: MRI (41.8%), relapses (4.6%), or both MRI and relapse (9.2%). “What's driving the detection of disease activity in this population is the frequency of MRI monitoring”, said Prof. Giovannoni. He concluded that incorrectly defining patients as naSPMS can result in reduced monitoring and decrease the chance to detect and treat any new disease activity in these patients.