Expert opinion: Criteria for second-line treatment failure in patients with multiple sclerosis

In the management of multiple sclerosis (MS), defining criteria for identification of suboptimal therapy responses and switching treatment is essential to avoid worsening. Despite the lack of a standardised definition, criteria for first-line treatment are well documented in the literature, based on clinical measures or magnetic resonance imaging (MRI) (gadolinium enhancing [Gd⁺] lesions or new/enlarging T2 lesions) assessed during the first 6-18 months after treatment initiation. However, it is unknown whether the same criteria can be used for second-line treatment failure.

Five regional boards involving 36 French MS experts were convened to discuss published literature regarding criteria for first- and second-line treatment failure, and to identify differences in local therapeutic practices. A national board of 11 experts was subsequently conducted to identify convergences and differences between regions, and to propose second-line criteria for the definition of therapeutic failure.

Published information is lacking regarding second-line treatment failure criteria. In light of this, regional differences in current therapeutic practices are justifiable. Due to the risk-benefit ratio of these treatments and limited options for third-line treatments, the authors recommend a different therapeutic approach when assessing second-line treatment failure. The treatment switch for second-line treatment should be informed by confirmed disease progression, after 6 months, or combined clinical and MRI outcomes, but only after at least 1 year of treatment.

Experts compared therapeutic attitudes and practices regarding second-line treatment failure between French regions. They identified convergences that were used to propose a national agreement on second-line treatment failure criteria, which should be evaluated in real-life prospective cohorts.