In the USA, siponimod is approved in adults for the treatment of relapsing multiple sclerosis (RMS), including active secondary progressive MS (SPMS). Understanding washout requirements when converting from other disease-modifying treatments (DMTs) to siponimod is important in clinical practice and should be assessed prospectively.
To report results from an interim analysis of EXCHANGE (NCT03623243), a prospective, 6 month, multicenter, open-label, single-arm study evaluating safety and tolerability of overlapping effects when converting to siponimod from other DMTs.
Patients aged 18-65 years with advancing RMS, Expanded Disability Status Scale (EDSS) score of >2.0 to 6.5, and on continuous oral/injectable DMTs for ≥3 months at time of consent were included in the analysis. Patients were immediately converted to siponimod, except those previously on teriflunomide who required 11-14 days’ washout (with cholestyramine or activated charcoal). During days 1-6, siponimod was titrated from 0.25 mg to 2 mg. Primary endpoint was incidence of drug-related adverse events (AEs). About 100 patients are being enrolled in a parallel, novel virtual cohort, with telemedicine tools.
112 patients (1 in the virtual arm; 70.5% female) from 42 centers in the USA were enrolled, completed screening and were eligible for safety analysis (33.9% ongoing; 20.5% discontinued; 45.5% completed). At screening, 74.1% (n=83) of patients had relapsing-remitting MS, 21.4% (n=24) had SPMS, 3.6% (n=4) had primary progressive MS and 0.9% (n=1) had a single demyelinating event; 42.0% (n=47) had ≥1 relapse in the prior 12 months. At baseline, median age was 45.5 years, median time since MS diagnosis was 11.2 years and median EDSS score was 3.5. In the safety analysis set, ≥1 drug-related AE was reported in 34.8% of patients (n=39) (95% confidence interval [CI]: 26.2-44.5); 4.5% (n=5) had ≥1 serious AE and 5.4% (n=6) had ≥1 AE leading to drug discontinuation. In the subgroup of patients who had completed or discontinued from the study (n=74), 40.5% (n=30) (95% CI: 29.5-52.6) had ≥1 drug-related AE. Change from baseline in heart rate to 6 hours post first dose and AEs by prior DMT will be presented.
Conversion from oral/injectable DMTs to siponimod without washout had a good safety and tolerability profile with no unexpected findings. Subsequent analyses will include data on conversion to siponimod from infusible (natalizumab/ocrelizumab) DMTs.