Immune thrombocytopenia (ITP) is an acquired immune-mediated disorder defined as a peripheral blood platelet count <100 x 109/L with no known cause. In this excerpt of the transcript from her nursing continuing professional development (NCPD)–approved activity, Immune Thrombocytopenia: Evolving Treatment Paradigms and Patient-Centered Care, Allison Miller Imahiyerobo, APN, an advanced practice nurse at the Hematology and Oncology Physicians of Englewood, discusses the pathogenesis of ITP, emerging ITP therapies, and evidence-based strategies in the treatment and care of patients with ITP.
Allison Miller Imahiyerobo, APN: For many years, we all thought thrombocytopenia was a disease of platelet destruction in the body, and it was thought to be idiopathic. We called it "idiopathic thrombocytopenia" because we didn't really know the exact cause. Now we call it "immune thrombocytopenia," because we know that there's a lot of immune regulation that affects how platelets are both produced and destroyed. Classically, you know that ITP is a disease of platelet autoantibodies, in particular glycoproteins 2B and 3A. You know that there's a splenic uptake of platelets. We know that we have platelet autoantibodies, and we know that impaired T regulatory cells in the immune system also impact platelet destruction. But now in the last 15 years, we also know that patients with ITP have impaired platelet production.
The majority of our patients that have ITP are really trying to understand why they have ITP. In the majority (80%), we never really find a cause; it's idiopathic. More often than not, these are women, and they're patients that are older in age. About 20% of patients have secondary disease. They had an infection, a trigger, or they have had a prior history of autoimmune disease. These patients may have lupus or thyroid disease. They may have a strong family history of autoimmune disease. That's the minority of our patients.
Patients with ITP really struggle a lot. When we think about what the disease burden is, it's really a disease of the skin. When I'm looking at my patient and assessing them, I'm looking at their skin. Often, you'll see bruising. You can see bruising at a variety of platelet counts. Anywhere from 30,000 to 50,000, you're seeing some minor bruising. Some patients have very little bruising; petechiae happens even with a little bit of a lower platelet count. So, that's often a pending area; sock line, waistline, bra line, you will see petechiae. Oral blood blisters, you often see in the mouth when the platelet count is under 20,000 or 10,000. Then hematuria is something that I worry a lot about, when platelet count is under 10,000. When you have a patient presenting to your practice with ITP, you're going to do a blood count.
We want to think about how we define the disease. This has changed a little bit over the last 5 years. There were recently guidelines put out, which changed the way we define it. At your first 3 months, we have newly diagnosed cases. Persistent cases are 3 to 12 months and chronic cases are over 12 months. The reason that these definitions are important is that some patients will go into remission before the disease becomes chronic. I think it's important to realize that when you're discussing treatment options with the patient.
Commonly in my practice, I'm using either prednisone or dexamethasone to start, but there's a huge range of how you dose these medications. Prednisone can be dosed anywhere from 0.5 mg/kg, all the way up to 2 mg/kg per day. Usually, I'm giving 1 mg/kg per day, but that could be a big dose. Somebody is 80 kg and you give them 80 mg a day. I generally max out at that dose because I find that dose hard to take and usually recommend taking it in the morning. About 70%-80% of patients will respond. Usually, you're seeing a response within 4 to 7 days. I'll start them on steroids and then I'll bring them back in a week. We'll see where the count's at and then we kind of dose from there. The problem with the steroid, or the prednisone, is that you have to wean the patient off of it. Depending on how often you're seeing your patient, it could take weeks to wean your patient off steroids. Current guidelines are really recommending the minimal use of steroids due to the side effect profile.
We have three TPO (thrombopoietin) agents: eltrombopag, romiplostim, and avatrombopag. Let's talk a little bit about the TPO. The TPO agents have been out for over 10 years now, almost. They came out around 2007, 2008, and they have been life-changing for our patients with ITP. Before these agents, patients had literally steroids, more steroids, and then intravenous immunoglobulin (IVIG). The patients with chronic severe ITP were really struggling with the disease. The TPO agents really changed the landscape, because all of a sudden you could take a pill or get a shot and your platelet count would stay up; and this was life-changing for patients with the disease. Now about 80% of patients respond. If your patient doesn't respond to one of these agents, it's very reasonable that you switch to another that they may respond to. They're slightly different molecules. Patients will have a mixed response rate when you switch between each agent.
I think you can find a treatment that really works for every patient and that agrees with them and their lifestyle choices. The disease has changed a lot during my practice.
About Ms. Imahiyerobo
Allison Imahiyerobo, APN, is an advanced practice nurse at the Hematology Oncology Physicians of Englewood in New Jersey. She specializes in the treatment of patients with hematologic malignancies, with particular expertise in ITP. Ms. Imahiyerobo is a member of the American Academy of Nurse Practitioners and the Oncology Nursing Society, and she was the recipient of the 2018 Columbia University Irving Medical Center Liquid Nurse Practitioner of the Year Award. She has authored or coauthored numerous publications focusing on improving outcomes in patients with hematologic malignancies.
Edits have been made to this excerpt for the sake of clarity and brevity. Any views expressed above are the speaker's own and do not necessarily reflect those of Oncology Data Advisor. Gain additional expert perspectives from Ms. Imahiyerobo by completing the full complimentary NCPD activity.