Panelists: Ivy Altomare, MD, Duke University Medical Center; Terry Gernsheimer, MD, Fred Hutchingson Cancer Research Center; Keith R McCrae, MD, The Cleveland Clinic
Terry Gernsheimer, MD: There are new TPO mimetics coming down the pipeline, and I think those will be of interest, as well.
Ivy Altomare, MD: OK. I have heard of avatrombopag. Dr McCrae, what’s your experience, or knowledge with that compound?
Keith R. McCrae, MD: I think it’s an interesting agent. It’s like eltrombopag. It’s an oral agent. I think it’s structurally related. The biggest difference between avatrombopag and eltrombopag is that eltrombopag is affected by diet and must be taken separately from food. Avatrombopag is not. There is a small abstract at this meeting that suggests that there is efficacy in idiopathic thrombocytopenia purpura. It’s a small study, but it clearly shows efficacy. I think it’s an interesting agent, moving forward. And certainly, it may have a place in ITP treatment.
Ivy Altomare, MD: Yes.
Terry Gernsheimer, MD: The other thing I like about this drug is that they have not yet seen the hepatotoxicity that that is seen with eltrombopag. I usually don’t want to use eltrombopag if the patient has any liver disease. So, avatrombopag may be a little bit better, in that circumstance.
Ivy Altomare, MD: That’s great. Then, there’s a Bruton’s tyrosine kinase inhibitor. Does it have a name? It’s PRN1008?
Terry Gernsheimer, MD: Yes. That has not yet, as far as I know, been used in ITP. I think that those data are just starting. Theoretically, it seems like it should work. There’s phenomenal results in dog pemphigus. I saw the pictures. It’s amazing to see these dogs come in looking absolutely horrible. And then, complete recovery.
Ivy Altomare, MD: Yes.
Terry Gernsheimer, MD: But, it’s also probably going to have to be a drug that’s going to have to be taken continuously. It’s not going to be something that’s going to be the magic bullet.
Ivy Altomare, MD: Yes. Well, similar to the way you use it in CLL [chronic lymphocytic leukemia].
Terry Gernsheimer, MD: Exactly. It’s not surprising that it would work, I don’t think, for the same reason that it works in CLL. I think that’s when people started recognizing that this is, perhaps, a good way to go. In CLL, we saw that patients who had cytopenias, that were felt to be immune, autoimmune, were recovering.
Ivy Altomare, MD: Right. Dr McCrae, are there any other interesting compounds or new drugs that are being tested?
Keith R. McCrae, MD: Well, there’s an abstract at ASH, here, about rozanolixizumab. This is an inhibitor of the neonatal Fc receptor, which is an interesting Fc receptor. It is on endothelial cells, and basically degrades immune complexes and recycles and protects IGG. It’s essentially like getting a plasma exchange by getting an injection. It lowers your IGG levels, including your autoantibody levels. So, there’s a small study with that, here. There’s several companies that I know are developing these types of drugs for various things.
Ivy Altomare, MD: Yes. That would be a temporary response, then, similar to IVIG? Or, does it not induce that kind of...?
Keith R. McCrae, MD: It’s hard to say. Certainly, you would think of it as something that would need continuous treatment. But, on the other hand, it’s hard to know, over time, what will happen.
Ivy Altomare, MD: We’ll look for more data from that. I also believe there’s an abstract here, at ASH, about low-dose decitabine?
Keith R. McCrae, MD: Yes. That’s an interesting abstract. Basically, it looks at the effects of low-dose decitabine on various regulatory subsets of B cells and T cells, and states that this was given to some patients with ITP. But, we don’t have any reports on the platelet count. I think that measuring immune cells is an interesting biomarker—if it correlates with a response in ITP— but measuring the biomarkers without the ITP response—it’s hard to say much about that.
Ivy Altomare, MD: Correct. Any other new compounds, new data, or just general final thoughts about the management of this interesting disease?
Terry Gernsheimer, MD: We’re all looking for the magic bullet, obviously. I think what we’re looking for is that right target. And, to understand better the mechanism of the disease.
Ivy Altomare, MD: Yes, in different patients. It’s probably not “one size fits all.”
Terry Gernsheimer, MD: We don’t think this is 1 disease. Some of us believe that all ITP is secondary ITP, and you just have to find what that might be. But, I think we really need to start to understand the disease a lot better, so that we can start choosing the right patient for the right drug. This is really what we don’t know, which is why I sit down with patients and I say, “Here’s everything I have. Let’s talk about it.” Because, right now, I think it’s more, “What do you prefer?” As opposed to, “What’s going to work, specifically for you?”
Ivy Altomare, MD: Yes. I hope we get there. Dr McCrae? Final thoughts? I really loved what you said earlier about how, maybe, the right approach is to treat ITP like a malignancy, since your best outcomes are seen with upfront therapy.
Keith R. McCrae, MD: Yes. I agree with what Dr Gernsheimer said. We use this term, more and more—personalized medicine. But, in many cases, it’s still somewhat of a concept without much reality. But, in more and more cases (diseases), we are seeing it applied. Clearly, ITP is a heterogenous disease. We need to find biomarkers, and gene expression profiles, and things to put patients into categories, to decide what really is the best way to treat them. But, we’ve made a tremendous amount of progress over the last 10 years.
Ivy Altomare, MD: Yes. I’d like to thank you both, so much. It’s been very informative for me. And, thank you. On behalf of our panel, and myself, we thank you for joining us in this Peer Exchange® discussion.