We roughly distinguish two different classes of MS drugs. On the one hand, the so-called basic therapies, which can be given in cases of mild/moderate MS, and on the other hand, the highly effective therapies that should be used in active MS. Basic therapies include the interferon preparations and glatiramer acetate (e.g. Copaxone), but also the newer oral substances teriflunomide and dimethyl fumarate/diroximel fumarate. These basic therapies are often prescribed at the beginning of the disease because
- early MS is often equated with mild MS,
- the concept of escalation therapy underlies the treatment algorithm of the DGN guidelines,
- and some practitioners put the safety of the basic therapies in the foreground.
However, a basic therapy does not always guarantee complete control of the disease. Clinical and/or MRI activity may occur, necessitating an adjustment of the therapy. This adjustment can either be made by a vertical change of therapy, i.e. by switching to a highly effective therapy. Or the therapy switch takes place horizontally, i.e. within the group of the same potency, but by choosing a different therapy concept. For the decision between the two options, many colleagues wish for evidence-based decision aids, which indeed exist in the literature. For example, an evaluation of the Austrian MS register, which was published in the Journal of Neurology in 2023, could be mentioned (Guger et al. J Neurol 2023 Jun;270(6):3103-3111).
MS Register Data on Therapy Changes
Within the register, 669 patients were identified who switched horizontally from interferon preparations/glatiramer acetate to dimehylfumarate (n=223) or terfilunomide (n=446) and 800 patients who switched (vertically) to a highly effective therapy, mainly to fingolimod (n=523) or natalizumab (n=205). The so-called “vertical switchers” were younger, had a shorter duration of illness, a higher EDSS, and more MRI activity. After statistical adjustment of both groups, the annual relapse rate during the observation period was 0.39 for the horizontal switchers compared to 0.19 for the group that switched vertically to highly effective therapies. The cumulative probability of suffering a relapse was significantly higher in the group with the horizontal switch, as was the probability of discontinuing the therapy in the course of time. With regard to confirmed disability progression, there was no difference between the groups. Interestingly, there was a trend for the group of “vertical switchers” with regard to the confirmed improvement of disability.
Advantage for vertical switch
The study is interesting in that it proves an advantage for the vertical switch of MS preparations. Translated into clinical practice, this means that if a change of medication should be necessary, a more efficient drug should rather be chosen than to switch to a drug within the same efficiency class.
This post was translated from German to English with the help of AI.
