OPTIMUM was a multicenter, double-blind, active-comparator phase 3 superiority trial that assessed efficacy, safety, and tolerability of ponesimod 20 mg (PON) vs teriflunomide 14 mg (TER) in patients with relapsing multiple sclerosis (RMS). The primary endpoint of annualized relapse rate was met demonstrating PON’s superiority vs TER.
To assess treatment effect on disability progression using time to worsening of timed 25-foot walk (T25FW), 9-Hole Peg Test (9HPT), Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test [PASAT-3] , Expanded Disability Status Scale (EDSS) and composites of these endpoints.
OPTIMUM enrolled patients with RMS (EDSS:0-5.5), randomized (1:1) to daily PON or TER for 108 weeks. Change in MS functional composite (MSFC) Z-score (mean of T25FW, 9HPT, PASAT-3 Z-scores), and SDMT from baseline to Week 108 was assessed using Mixed-Effect Model Repeated Measures. Analyses of time to first confirmed (12-week) disability event were conducted post-hoc; disability was defined as 4-point worsening in SDMT, 20% worsening in T25FW or 9HPT, in addition to EDSS (as defined for the secondary endpoint).
Of 1133 patients (PON=567, TER=566), 86.9% completed study. Changes from baseline in overall MSFC Z‑score: 0.02 PON vs −0.039 TER (mean difference, 0.059; p=0.047); for the 3 individual components of MSFC Z-score, mean differences (p-values) were: T25FW, 0.20 sec (p=0.37); 9HPT, –0.93 sec (p<0.0001); PASAT-3, 0.55 number correct (p=0.16). The PON vs TER worsening events up to EOS were, respectively: confirmed 20% worsening in T25FW, 9.2% vs 13.1% (hazard ratio [HR]:0.70; p=0.045); 4-point worsening in SDMT, 22.1% vs 26.4% (HR:0.82; p=0.12)], composite EDSS/SDMT, 26.3% vs 32.7% (HR:0.80; p=0.045)]; composite EDSS/9HPT/T25FW, 18.2% vs 24.0% (HR:0.76; p=0.035); numerical differences in favour of PON in time to confirmed worsening in 9HPT and SDMT assessed individually were not statistically significant.
Measures of worsening of impairment and disability in this exploratory analysis indicated benefits for PON vs TER. Composite endpoints provide more power to statistical assessments owing to greater number of events analyzed, making them particularly useful in RMS trials.