Literature review and meta-analysis of natalizumab therapy for the treatment of highly active relapsing remitting multiple sclerosis in the 'suboptimal therapy' patient population

Background: Highly active (HA) relapsing remitting multiple sclerosis (RRMS) is associated with frequent relapses and high burden of disease/disability. Natalizumab is licensed for HA RRMS, including rapidly evolving severe (RES) (≥2 relapses in previous year) and sub-optimally treated (SOT) (≥1 relapse in previous year despite treatment) populations. However, there is limited RCT evidence in the SOT subpopulation.

Objective: To review the non-RCT evidence for natalizumab in SOT HA RRMS.

Methods: Databases were searched to January 2023 for non-randomised studies of natalizumab in HA RRMS. Studies in patients with ≥1 relapse during previous treatment were eligible for inclusion. Meta-analyses were conducted to compare natalizumab with platform and higher efficacy disease-modifying therapies, with sensitivity analysis restricted to studies of low risk of bias.

Results: Included comparative studies (n = 16) showed natalizumab had lower relapse rates, disease activity and MRI (radiological) outcomes compared with platform and higher efficacy therapy. Case series (n = 11) showed natalizumab was associated with high rates of freedom from relapse and clinical/radiological disease activity and reductions in annualised relapse rate and disability progression.

Conclusions: Literature reviewed indicates that natalizumab is more effective than other included treatments for SOT patients. Findings were consistent with studies in the broad HA RRMS population, suggesting that natalizumab may have similar efficacy for SOT and RES HA RRMS.