OBJECTIVES The purpose of this analysis was to estimate how higher persistence in RRMS patients treated with interferon beta 1-a and its electronic injection device (Rebismart®) affects the rate of escalation to 2^nd line therapies.  METHODS A 2-year, decision-analytic model was developed to track a hypothetical cohort of 1,000 RRMS patients initiating treatment with either interferon beta 1-a and Rebismart® or another 1^st line self-injectable disease modifying drug (DMD). The model calculated the expected probability of escalating to 2^nd line therapy, which was defined as either Gilenya® or Tysabri®.  Persistence curves were estimated from a real-world dataset collected from the UK NHS where at 2 years Rebismart® users had 83% persistence vs. 60% in non- Rebismart® users.  A market research study was utilized to determine the treatment pathways for non-persistent patients, where 39% transitioned to another 1^st line DMD; 21% abandoned therapy and 40% escalated to 2^nd line therapies. One-way sensitivity analyses (OWSAs) varied the probability of non-persistent 1^st line patients escalating to 2^nd line therapies from 5% to 100%. RESULTS The model estimated that over two years 5.4% of patients on the Rebismart® device are expected to escalate to 2^nd line therapy, while 18.3% of patients that initiated treatment on other DMDs are expected to escalate.  At the lower bound of the OWSA, 0.68% of patients are expected to escalate on Rebismart®, vs. 2.3%; while at the upper bound of the OWSA, 13.3% of Rebismart® patients are expected to escalate vs. 42.7%.  CONCLUSIONS Higher persistence rates in RRMS patients initiating treatment with interferon beta 1-a and the Rebismart® electronic device are expected to result in fewer escalations to 2^nd line therapies relative to other self-injectable DMDs.