090 The effect of cladribine tablets on delaying the time to conversion to clinically definite multiple sclerosis (MS) or McDonald MS is consistent across subgroups in the ORACLE-MS study

Abstract

IntroductionIn the Phase 3 ORACLE-MS trial in 616 subjects with a first demyelinating event at high risk of converting to multiple sclerosis (MS), treatment with cladribine tablets 10 mg (3.5 mg/kg or 5.25 mg/kg cumulative dose over 2 years [CT3.5 and CT5.25, respectively]) significantly delayed time to conversion to clinically definite multiple sclerosis (CDMS) according to Poser criteria (67% or 62% risk reduction [RR], respectively) and time to conversion to 2005 McDonald MS (50% or 57% RR, respectively), versus placebo. The objective was to analyze the effect of cladribine tablets vs placebo on converstion to CDMS and McDonald MS across ORACLE-MS patient subgroups based on baseline characteristics.MethodsIn this post-hoc analysis, time-to-conversion to CDMS or McDonald MS over the double-blind period was analyzed for patients treated with CT5.25 (N=204), CT3.5 (N=206) or placebo (N=206) across different subgroups. Subgroups were defined by baseline characteristics which have been investigated as potential predictors of CDMS conversion (age [<30 or ≥30 years], gender, first classification demyelinating event [monofocal or multifocal], presence of T1 Gd+ lesions and number of T2 lesions [<9 or ≥9]).ResultsTreatment with CT3.5 or CT5.25 was consistently efficacious across the subgroups examined on conversion to CDMS versus placebo for most comparisons (RR range: CT3.5, 39%–72%; CT5.25, 36%–79%). Similarly, treatment effect of both doses on conversion to 2005 McDonald MS was consistent across subgroups (CT3.5,40%–59%;CT5.25,42%–79%).ConclusionsThe effect of cladribine tablets on delaying the time-to-conversion to CDMS, or to McDonald MS, is consistent across subgroups.