Short-term laboratory and related safety outcomes for the multiple sclerosis oral disease-modifying therapies: an observational study

Real-world safety data for the oral multiple sclerosis (MS) disease-modifying therapies (DMTs), dimethyl fumarate (DMF), fingolimod, and teriflunomide are important. We examined laboratory test abnormalities and adverse health conditions in new users.

Linked laboratory and administrative health data were accessed for all persons with MS (PwMS) filling their first oral DMT prescription in two Canadian provinces. PwMS were followed from first prescription fill until discontinuation, death, emigration or study end. Proportions of PwMS, and incidence rates (IR)/100 person-years, were calculated for ≥1 event of elevated alanine aminotransferase (ALT) (>the upper limit of normal [ULN]; all DMTs), liver toxicity (ALT>3xULN; fingolimod); lymphopenia and proteinuria (DMF), and cardiac arrhythmia, hypertension and pneumonia (all DMTs).

Overall, 1,140 PwMS were followed for up to 2 years. De novo elevated alanine aminotransferase affected 13.2% (DMF), 12.4% (teriflunomide), and 30.0% (fingolimod) of users. Liver toxicity affected 2.8% of fingolimod, lymphopenia 3.1% of DMF, and proteinuria 2.9% of DMF users. The incidences of cardiac arrhythmia, pneumonia and hypertension ranged from <1 to 1.86/100 person-years depending on the DMT.

The short-term, real-world incidences of abnormal laboratory results or adverse events were consistent with the pivotal clinical trial findings. Longer-term safety data are still needed.