To report on the post-approval safety profile of subcutaneous interferon beta-1a (sc IFNβ-1a) in patients with relapsing multiple sclerosis (RMS), including COVID-19 and other respiratory viral infections.

sc IFNβ-1a is a well-established disease-modifying therapy for RMS, with an estimated cumulative exposure of 1,831,698 patient-years (to 30 April 2021).

Serious and non-serious adverse events (AEs)/adverse drug reactions (ADRs) from post-approval spontaneous individual case safety reports are presented cumulative to May 2021. AE rates are shown as total number of patients. Current COVID-19 findings are summarized.

A total of 527,833 ADRs have been reported; 6.6% of events were serious. Analysis of the most common respiratory viral infection ADRs reported spontaneously (influenza [2374 cases, constituting 0.45% of all ADRs], viral infection [319], H1N1 influenza [15], viral bronchitis [6], and viral upper respiratory tract infection [5]) did not reveal any abnormal trend outside the known safety profile of sc IFNβ-1a; cases were typically non-serious. There was no suggestion of an increased risk of more severe respiratory viral infection or other ADRs in RMS patients who experienced such infection while being treated with sc IFNβ-1a. As of 17 August 2021, the Merck KGaA safety database included 1256 suspected or confirmed cases of COVID-19 in sc IFNβ-1a treated RMS patients; the majority were non-serious events. Among confirmed cases (n=1029), 110 patients were hospitalized with 5 requiring mechanical ventilation. There were 24 fatalities (18 fatal COVID-19 events and 6 other fatalities unconfirmed for COVID-19 involvement). At time of reporting, around half of COVID-19 confirmed AEs were recovered or resolving.

Cumulative to 17 August 2021, there was no increased risk of COVID-19 in sc IFNβ-1a treated RMS patients and the majority of cases were non-serious, consistent with previously reported registries. No new safety concern was identified from post-approval cases in scope of this review.