So thrombopoietin receptor agonists are a mainstay of treatment of ITP in 2023, but these agents have been around for about 15 years in ITP. For the longest time we really had romiplostim and eltrombopag and we didn’t have a whole lot of long-term data. Now we have long-term data for those agents, and we have new agents like avatrombopag and hetrombopag. Hetrombopag currently limited to China but there’s investigations that are starting with this drug outside of China and in the West...
So thrombopoietin receptor agonists are a mainstay of treatment of ITP in 2023, but these agents have been around for about 15 years in ITP. For the longest time we really had romiplostim and eltrombopag and we didn’t have a whole lot of long-term data. Now we have long-term data for those agents, and we have new agents like avatrombopag and hetrombopag. Hetrombopag currently limited to China but there’s investigations that are starting with this drug outside of China and in the West. So, these new agents really are helping to change the landscape as well as some of the long-term safety data. We now really understand quite well that, you know, initial concerns like myelofibrosis and the risk of leukemogenesis with these agents really at least for romiplostim/eltrombopag, clearly, you know, those initial concerns have not borne out. So, we have that long-term safety data that makes us comfortable using these agents is probably true for the newer agents, too, but we don’t have that data yet for them. But newer agents like avatrombopag allow for patients to receive an oral therapy without dealing with all of the dietary restrictions that eltrombopag has and without dealing with the risk for hepatotoxicity. So, we now have a number of different options for ITP patients and it’s important to have a discussion with the patients regarding their, you know, preferences for treatment and finding the right agent for them. Also, we now recognize that whether we’re switching between romiplostim and eltrombopag, or eltrombopag and avatrombopag, the chances of success are quite high with switching, even greater than 50% in those patients who did not respond to the first agent. We know this from a number of studies that have been done involving these three agents and some new data with hetrombopag as well showing similar success rates after switching. So, switch for a good reason, not for no reason, but you’re likely to have response whether you’re switching for convenience, adverse effects or ineffectiveness of the prior agent. We are also recognizing now with the question of tapering of thrombopoietin receptor agonists, to try to induce a sustained response off treatment and sort of irrespective of the study in all of these have been done with eltrombopag or romiplostim, we have about a one third chance of success on average to get the patients into a sustained response off treatment. In other words, an acceptable platelet count, not necessarily a normal platelet count. I use the word response rather than remission, off treatment without any ITP directed treatment after tapering off, those patients that have been on a thrombopoietin receptor agonist for a year or longer, who regularly maintain a count of above 100,000, are good candidates to try this.
