However, this is a very valid question. Because in contrast to the “relatively” rare primary progressive MS (PPMS), most people with MS with a chronic progressive course belong to the group of secondary progressive MS. “Secondary progressive MS” (SPMS) refers to the stage that many patients with relapsing MS reach after individually different times, especially when control of CNS inflammation has been suboptimal for a long time. It is the phase of the disease in which relapses can still occur (but much less frequently) and in which a slow deterioration of neurological deficits is the main focus. So a development that we want to prevent in every MS patient who starts with relapses…
Now, you probably have heard or maybe even read in this blog, that the new drug Ocrelizumab (Ocrevus®) was approved for primary progressive MS because it was able to show effectiveness in this group of patients. However, since the substance has never been tested in patients with secondary progressive MS (i.e., “late-stage relapsing MS”), there is no approval for this form of disease – and therefore, if doctors prescribe Ocrevus® for SPMS anyway, they could be taken to task by health insurance companies because strictly speaking it is an “off-label” prescription. Accordingly, patients with SPMS will not receive a recommendation for this new therapy.
Does the inadequate study situation also mean that the use of Ocrelizumab in SPMS patients makes no sense? I would not see it that way. From my point of view, Ocrelizumab – as a strongly anti-inflammatory substance – could be useful in SPMS patients who still have relapses and signs of activity on MRI. After all, this is exactly what the study on PPMS showed: in particular, patients who show signs of active disease benefit.
This teaches us two things. Firstly, we neurologists should be very sparing with the term SPMS – especially early in the disease and as long as there is still disease activity in the form of relapses and MRI activity. Because by classifying as SPMS, patients are excluded from treatment options that could potentially benefit them and limit the therapeutic spectrum.
Secondly, we should probably change our classification systems – as I described in the article on PPMS. It would be more appropriate to distinguish between an active and an inactive disease, regardless of the duration of the disease. Because with an active disease, the use of anti-inflammatory drugs can prove to be effective, while inactive courses probably need other strategies. But as long as there is still activity, patients will benefit from anti-inflammatory approaches, especially from the newly approved B-cell-depleting approach.
In this context, it may also be good news that there are now substances that have been tested in SPMS patients and were able to show an effect in this group (even late in the course). The successor substance to Fingolimod, called Siponimod, which is better tolerated than Fingolimod, was recently able to show an effect in SPMS patients in a large worldwide study. And by the way, the results were very similar in scope and extent to the results of Ocrelizumab in PPMS.
