Stick or twist? Cost-effectiveness of siponimod compared with continuing existing disease-modifying therapies in the treatment of active secondary progressive multiple sclerosis in the UK

Objective Identification of the phenotypic transition from relapsing-remitting multiple sclerosis (RRMS) to secondary progressive multiple sclerosis (SPMS) is often delayed due to disease complexity and an unwillingness to withdraw RRMS disease-modifying therapies (DMTs), driven by limited SPMS treatment options. Despite the paucity of clinical evidence for efficacy in patients with SPMS, DMTs licensed for RRMS are frequently continued into the early stages of SPMS. The cost-effectiveness of oral siponimod, an active SPMS DMT, versus continued oral or infused RRMS DMTs for patients with active SPMS, was evaluated. Methods A cohort Markov model based on disease progression through Expanded Disability Status Scale health states, with annual cycles and lifetime horizon, was employed to determine the cost-effectiveness of siponimod from a UK National Health Service (NHS) perspective for patients with active SPMS. Baseline characteristics, health state utility values, hazard ratios for time to 6-month confirmed disability progression, annualized relapse rate ratios and adverse events for siponimod were obtained from the phase 3 EXPAND clinical trial, supplemented by published literature. Published costs, resource use data and comparator efficacy data were obtained from the literature and, in the absence of data, reasonable assumptions were made. Results Quality-adjusted life years (QALYs) were greater for siponimod versus all comparators (3.45 versus 2.69-2.83). Incremental cost-effectiveness ratios (ICERs), calculated as cost per QALY, for siponimod versus natalizumab (dominant), ocrelizumab (4,760) pound, fingolimod (10,033) pound and dimethyl fumarate (15,837) pound indicated that siponimod was cost-effective at the commonly accepted willingness-to-pay threshold of 30,000 pound/QALY. Conclusions Recognition of active SPMS and treatment of this phenotype with siponimod offers a cost-effective and clinically beneficial treatment approach compared with the continuation of oral or infused RRMS DMTs.