To assess short term relapse and disability risk after switching from fingolimod (FTY) to ocrelizumab (OCR) or cladribine (CLAD) in patients with relapsing-remitting multiple sclerosis (RRMS)

Severe return of disease activity has been reported in smaller heterogeneous case series in around 10% of patients (irrespective of following treatment). Information on disease activity when switching MS medication from FTY to OCR/CLAD is scarce.  

Patients were recruited from several academic centers (AC) throughout Europe (Germany/ Norway) and two national registries (Denmark (DMSR)/ Germany (GMSR)).  

We included 254 adults with RRMS who stopped FTY (treated ≥3 months) and switched to OCR/CLAD within 6 months after last FTY intake and had at least 6 months follow up on OCR/CLAD (exposure). 

The frequency of relapses was assessed in different phases after FTY was discontinued.

196 patients (DMSR: N=75, GMSR: N=63, AC: N=58) switched from FTY to OCR, 58 patients (DMSR: N=15, GMSR: N=17, AC: N=26) from FTY to CLAD.

In the treatment free switching interval regardless of following switch treatment 23/9.06% patients had ≥1 relapse in 41.74 patient years (py) (DMSR: N=6/6.67% in 14.47 py, GMSR: N=3/3.75% in 13.74 py, AC: N=14/16.67% in 13.53 py).

During the first six months after OCR/CLAD start 29/11.42% patients had ≥1 relapse regardless of switch treatment.  

Stratified by drug type 18/9.18% of the OCR switchers (DMSR: N=4/5.33%, GMSR: N=8/12.7%, AC: N=6/10.34%) and 11/18.97% of the CLAD switchers (DMSR: N=1/6.66%, GMSR: N=1/5.88%, AC: N=9/34.62%) had ≥1 relapse. 

Around 20% of FTY switchers to OCR or CLAD experienced a relapse; the relapse risk varied depending on data source and was highest in AC.