Safety and tolerability of conversion to siponimod from other disease-modifying therapies in patients with advancing forms of relapsing MS: Results from the EXCHANGE study

Background: Siponimod, a sphingosine-1-phosphate (S1P) receptor modulator, reduces relapses and delays disability progression in patients with active progressive multiple sclerosis (MS). Objective: EXCHANGE assessed the safety/tolerability of siponimod in patients with advancing relapsing MS (RMS) converting from other disease-modifying therapies (DMTs). Methods: This 6-month, open-label, multicenter, single-arm, phase 3b study (NCT03623243) enrolled 185 patients with advancing RMS previously treated with other DMTs for ⩾3 months. Patients were converted to siponimod via a 6-day dose-titration regimen, or converted immediately, depending on prior DMT use. Results: Treatment-related adverse events (AEs) were reported by 31.9% (59/185) of patients, with headache (8.1%, n = 15), dizziness (3.8%, n = 7), and nausea (3.2%, n = 6) most commonly reported. Overall, an increase in heart rate (HR) 6 hours following the first dose of siponimod was observed (+2.47 bpm [0.66; 4.29]; p = 0.008). Patients switching from fingolimod without dose titration experienced no change in HR. Serious AEs were reported by 4.9% (9/185) of patients, and 8.6% (16/185) of patients discontinued the study treatment due to AEs. Conclusion: Conversion to siponimod from other DMTs was found to be generally well tolerated. Patients switching from other S1P-receptor modulators may be able to immediately transition to the siponimod maintenance dose without effects on HR. Clinical Trial Registration: ClinicalTrials.gov: NCT03623243 (https://clinicaltrials.gov/study/NCT03623243)