Experts take a dive into available therapies and optimal treatment strategies for idiopathic inflammatory myopathies.
W. Hayes Wilson, MD: Let’s talk about idiopathic inflammatory myopathies: dermatomyositis, and polymyositis. What factors guide your treatment with idiopathic inflammatory myopathies?
Kostas N. Botsoglou, MD: If there’s any organ involvement, like interstitial lung disease, that will determine which agents I may select, and how elevated their CPKs [creatine phosphokinase levels] can be. Are they able to function? Are they able to ambulate and so forth? If they’re having the rash, I make sure that they’re being worked up for any malignancies and they’ve done their appropriate screenings for colon cancer or pap smears, if applicable. It’s just watching the trend of their inflammatory markers and their muscle enzymes. This is how we gauge our response.
W. Hayes Wilson, MD: Age of onset means a lot. I suppose with dermatomyositis, I don’t really see kids. Do you see kids?
Kostas N. Botsoglou, MD: I do not.
W. Hayes Wilson, MD: We worry about malignancy and dermatomyositis in children. But in those of us who are chronologically gifted, have a little bit of white hair, we worry about that with our patients. And certainly, common things are common. You’ve already mentioned breast cancer or pap smears, in men prostate exams and colonoscopies, chest x-rays. Those are all good things. And looking at other risk factors. Because I’m sure that you as I have seen the coexistence of inflammatory myopathies and malignancy. And to that end, we also want to be careful about what we choose to treat our patients with. We might start with corticosteroids. Tell me how you look at that, and maybe touch on repository corticotropin injection as well.
Kostas N. Botsoglou, MD: The cornerstone in this situation is corticosteroids. I typically start at 1 mg/kg. I don’t exceed 80 mg/kg; usually 60 mg/kg is the max. It’s a gradual taper that takes several weeks. We try to get them down, again, maybe every 1 to 2 weeks, decrease by 5 mg or 10%. My goal is to get them to 10 mg or less. And many times, that is not easily possible. We’ll throw in a steroid-sparing DMARD [disease-modifying antirheumatic drug], such as methotrexate or azathioprine, to help bridge that gap. But if I can’t get them below 10 mg or they keep flaring up, or they keep having exacerbations with profound weakness and their muscle enzymes continue to climb despite an industrial dose of corticosteroids, that’s when corticotropin is a great option for these patients. I’ve seen them respond rather quickly once I start them on treatment. I start them typically at 80 units twice a week, and within the first 2 weeks, they notice a profound difference. And of course, I’m weaning the prednisone or steroids while they’re on repository corticotropin.
W. Hayes Wilson, MD: I use it the same way as you would. The repository corticotropin injection is helpful in patients who don’t respond to conventional therapy. One of its proposed mechanisms of action is to have a direct effect on myocytes. I would find it helpful in that regard as well. One of the questions my patients will ask me is, “How long do I have to take this? Do I have to take this for the rest of my life?” And I always tell them, it’s not a sentence. It’s a management tool. I tell them to take it as long as you need it, not any longer; take as much as you need, not anymore. I use it very much the same way as you do, 80 units twice a week. And I usually tell them, why don’t we do it in 12-week blocks? Because that’s how the studies were done. We’ll assess in 12 weeks. It’s like eating an elephant. When you break it off into pieces like that, it’s a little bit easier for them to digest, I’ll say. I’m not sure I’ve ever had an elephant. No, I’m pretty sure I haven’t. But you know what I mean?
Kostas N. Botsoglou, MD: Exactly.
W. Hayes Wilson, MD: Are there other corticosteroid-sparing agents you might have employed? What have you tried, and how do you choose one or the other?
Kostas N. Botsoglou, MD: Again, it depends if there’s any comorbidities. If they have elevated liver functions, perhaps methotrexate is not an ideal option. If they can’t metabolize azathioprine, that’s not a good option. I’m just borrowing other DMARDs from our other conditions. Rarely, I’ve used mycophenolate, but it’s really corticosteroids. That’s the mainstay, and that’s why I have had more patients end up going on a repository corticotropin because I’ve seen such a great response, and it’s such an unmet need in this condition. And going back to the dosing, it has flexible dosing as well. I have patients who after 12 weeks of 80 units twice a week, can maybe go down to 80 units once a week, or perhaps 40 units twice a week. There’s a little flexibility in the dosing. Once patients have a taste of heaven, nothing tastes the same.
W. Hayes Wilson, MD: There’s nothing that helps with success, like success. Yes, I’ve used azathioprine, I’ve used methotrexate, and occasionally, I’ve used them together. Intravenous immunoglobulin, I don’t use a lot, but I’ve found that to be effective in some patients. And of course, our old standby hydroxychloroquine and chloroquine. Have you used, or do you use rituximab in inflammatory myopathies?
Kostas N. Botsoglou, MD: I have used it on occasion, yes. I have used it with some success. It’s more of a last line for our patients.
W. Hayes Wilson, MD: One of the issues is, it’s tricky getting it paid for.
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Transcript edited for clarity.