Symptom Control in gMG: Comparing Ravulizumab and Efgartigimod

Announcer:
You’re listening to NeuroFrontiers on ReachMD. On this episode, we’ll hear from Dr. Christopher Scheiner, who’s a neurologist at the University of Tennessee Medical Center. He’ll be discussing his research on how two different therapies control symptoms in patients with myasthenia gravis. Here’s Dr. Scheiner now.

Dr. Scheiner:
The purpose of this study was to evaluate symptom control in generalized myasthenia gravis patients who are antibody positive and are taking two of the available biological medications now: ravulizumab or efgartigimod. Ravulizumab is a complement inhibitor; it has an 8-week dosing cycle, meaning that after an initial dose, two weeks later you get it every eight weeks. And then efgartigimod is an FcRn inhibitor that basically has a variable pattern of dosing, but in general, it’s prescribed one month on, one month off, with doses that occur every week. So the idea here is that we have two medicines that are different in their dosing strategies and different in their mechanism, and we wanted to see just how well these medicines controlled myasthenia gravis symptoms over time. And the way that we did that was we had to go back to the source data of their original clinical trials because there is no direct head-to-head comparison on this. 

We took the data from the CHAMPION trial for ravulizumab, and the data from the ADAPT trial for efgartigimod. And the challenge was that they’re not exactly the same in terms of the patient monitoring, the number of patients, and the duration of the trials, but what we had to do was take a look and see if we could find a way to compare within the context of each trial how well patients’ symptoms were controlled at each visit. For the CHAMPION trial we had, I think, seven different measuring points over the course of about six months, and for the ADAPT trial, there were nine different time points scattered over 10 weeks. So what we were trying to do is we were trying to look at the CHAMPION data and the ADAPT data and use the data contained within those studies themselves to see whether or not patients were stable, improving, or worsening over time on each medication.

Basically, the results of the study showed that both drugs are effective at treating myasthenia gravis. So I’m not going to take anything away from either drug in that regard. But where I think we saw some differences is that patients on efgartigimod tended to spend more time either getting better or getting worse. And what do I mean by that? What I mean by that is that just the cyclical nature of the dosing strategy of efgartigimod means that when a patient is receiving the medication, they tended to improve, but then when they were off the drug, they tended to decline, so you saw this sinusoidal wave-like pattern of improvement and decline in their MG-ADL scores, which was the measurement that we used to make this determination, whereas in the ravulizumab patients, they tended to improve and remain stable.

Some caveats that I think I have to point out about our study is that there’s a lot of different ways to dose efgartigimod, and I think the study tried to do a very good job of looking at seven different regimens that were used in the ADAPT trial, but there’s really not a great way to compare it directly. This is just the best we can do based on the trial data, right? So the idea here is that it’s not a direct head-to-head comparison; it’s an indirect comparison. And in a lot of ways, I think the variability of dosing of efgartigimod is one of the things that we would always have to point out as being something that would give anybody pause in overinterpreting these results. I think the results are fine and they’re good as they were presented, but again, if there’s a different way to dose efgartigimod or if there’s a dosing strategy that could improve its results, that might have changed the outcomes of the study. So with that little bit of hand waving, I’ll say that’s really how we have to interpret this data.

Announcer:
That was Dr. Christopher Scheiner talking about his research on how two distinct treatments manage symptoms in patients with myasthenia gravis. To access this and other episodes in our series, visit NeuroFrontiers on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!