Secondary progression activity monitoring in MS despite an early highly active treatment the SPAM study.

Background: Real-world data suggest that the early use of highly active therapies (HAT) may reduce the risk of transition to secondary progressive MS (SPMS). However, current knowledge about predictive factors of outcomes needs to be improved. The primary objective of this study was to determine factors associated with the occurrence of SPMS in patients treated early after MS onset with an HAT.

Methods: Retrospective, multicentric study based on the French MS database. Patients who initiated a HAT within 5 years after MS onset, EDSS ⩽4, and had a follow-up >5 years were included. The association of each covariate at baseline with time to the occurrence of SPMS was quantified by hazard ratios (HRs) in unadjusted and adjusted Cox proportional hazards models.

Results: Two thousand two hundred and thirty-seven patients were included in the analysis: mean age 31.6 years, female/male sex ratio 2.3, and median EDSS 2.0. The estimated probability of reaching SPMS, progression independent of relapse activity (PIRA) and progression independent of activity (PIA) at 10 years was 8%, 22%, and 11%, respectively. After adjustment, we found that female patients (HR 0.64, p = 0.036) had a lower risk of developing SPMS. Older age, EDSS >0 (HR 7.44, p < 0.001), and oral versus intravenous HAT (HR 1.97, p = 0.003) were significantly associated with an increased SPMS risk. Early PIRA and PIA predicted conversion to SPMS.

Conclusions: Early HAT use resulted in a low risk of developing SPMS over 10 years. Introducing the HAT before any residual disability was associated with a lower risk of progression.