Use of subcutaneous natalizumab in routine care - Final results of a non-interventional, observational study (SISTER) in Germany and Austria

Natalizumab is a disease-modifying therapy for patients with relapsing-remitting multiple sclerosis (RRMS). In addition to its original intravenous (IV) formulation, a subcutaneous (SC) route of administration (RoA) was approved in 2021. Subsequently, the observational SISTER study was initiated in Germany and Austria to generate real-world data on the utilization, patient preferences, safety, and effectiveness of natalizumab in everyday clinical practice.

The primary objective was to compare patients' preference of RoA and satisfaction with SC vs. IV natalizumab at baseline and up to 12 months of treatment. Secondary objectives included drug utilization, effectiveness outcomes, safety, and treatment satisfaction with natalizumab.

SISTER was a prospective, multicenter, observational study on RRMS patients who were allocated to 3 parallel treatment cohorts: Patients switching from IV to SC natalizumab (SC switcher) and patients starting natalizumab on either the SC or IV route (starter SC/IV).

The final study analyses were based on 310 patients (220 switchers, 44 SC starters, 46 IV starters) with an observation period of 10.8±3.1 months.

Patient preference for the initial RoA at baseline was 95.1% among SC starters and 77.5% among IV starters (p=0.045). More IV starters than SC starters or SC switchers at baseline and Month 6 wished to change the initial RoA. Disease activity remained low in all cohorts, and the AE pattern was consistent with the known safety profile of natalizumab. The procedure duration was distinctly shorter on SC treatment than on IV treatment.

The final SISTER results suggest a patient preference for the SC vs. IV route and support the outcomes of the NOVA Part 2 trial, in which the preference of the SC route over IV was demonstrated in a cross-over design. The SC route allowed relevant time savings, and its good safety and tolerability argues for possible self-administration of SC natalizumab.