OBJECTIVES: Oral fingolimod is supposed to be more effective and convenient to be administered by individuals with Multiple Sclerosis (MS) than injectable disease Modifying Agents (DMAs). However, existing evidence regarding the comparative adherence trajectories between oral and injectable DMAs is not yet explored. Hence, the objective of this study was to compare the adherence trajectories between oral fingolimod and injectable DMA users with MS.

METHODS: A retrospective longitudinal study was conducted using adults (≥18 years) identified with MS (ICD-9-CM: 340 and a DMA prescription) from IBM MarketScan Commercial Claims and Encounters Database during 2010–2011. Patients were classified as oral fingolimod or injectable users based on the index DMA among patients with MS. The DMA adherence trajectories based on Proportion Days Covered (PDC) were examined using Group-Based Trajectory Modeling (GBTM) during the one year after treatment initiation. Multivariable multinomial regression using stabilized Inverse Probability Treatment Weights (IPTW) was preformed to assess the association between the route of administration (Oral vs. Injectable) and adherence trajectory group.

RESULTS: The study cohort consisted of 1,700 MS patients who were initiated with oral (15.82%) or injectable (84.18%) DMAs during 2010-2012. The adherence rate (PDC≥0.8) among oral fingolimod and injectable DMA users was found to be 64.68% and 50.80%, respectively. GBTM grouped study subjects into three adherence trajectories – Complete Adherers-55.76%, Slow Decliners-37.24% and Rapid Discontinuers-7.00%. The multinomial regression model with stabilized IPTW revealed that fingolimod users had lesser odds to be a rapid discontinuer (adjusted odds ratio [AOR]-0.38, 95% CI:0.20-0.73) or a slow discontinuer (AOR-0.53; 95% CI:0.40-0.71) relative to injectable DMA users.

CONCLUSIONS: Oral fingolimod use was associated with better adherence trajectory than injectable DMAs. More research is needed to evaluate the adherence trajectories with other newer oral DMAs introduced in the last decade among individuals with MS.