Switching to Romiplostim Offers Little Benefit for Children After Multiple Oral TPO-RA Failures

For children with immune thrombocytopenia (ITP) whose platelet counts refuse to rise despite repeated treatment attempts, one of the most persistent questions in pediatric hematology has been whether it is still worth trying yet another drug from the same class. A new retrospective study from Beijing Children’s Hospital, published in Annals of Hematology, delivers a sobering answer: for children who have already failed multiple oral thrombopoietin receptor agonists (TPO-RAs), switching to the injectable agent romiplostim appears to offer minimal benefit, and clinicians may need to look beyond this drug class entirely.

ITP is an autoimmune bleeding disorder in which the immune system destroys platelets and suppresses their production in the bone marrow. In children, the condition often resolves on its own, but a substantial minority develop persistent or chronic disease requiring second-line therapy. TPO-RAs, which stimulate platelet production by activating the thrombopoietin receptor on megakaryocytes, are recommended second-line treatments. The class includes oral agents such as eltrombopag and avatrombopag, and the injectable peptide-mimetic romiplostim. When one agent fails, guidelines have suggested that switching within the class, particularly from an oral drug to romiplostim, may still succeed, because the agents differ in structure, metabolism, and pharmacology.

That assumption, however, had never been rigorously tested in the specific scenario that matters most: children who have failed not just one but several oral TPO-RAs. The Chinese research team, led by Shuyue Dong and Yumeng Jia with senior authors Xiaoling Cheng and Runhui Wu, was able to examine this question thanks to a unique real-world circumstance. Romiplostim reached the market late in China, which meant that children there often received it only after prolonged exposure to, and failure of, multiple oral TPO-RAs. This sequencing created a natural experiment that would be difficult to construct deliberately.

The study was a single-center, retrospective, observational analysis of patients aged 1 to 18 years with persistent or chronic ITP who received romiplostim for at least four weeks. The researchers assessed clinical characteristics, prior therapies, platelet response, bleeding outcomes, the need for rescue therapy, and adverse drug reactions. The work was approved by the Medical Ethics Committee of Beijing Children’s Hospital, and all patients provided written informed consent. The study was registered as ChiCTR2400086099 and funded by the National Key R&D Program of China and the National Natural Science Foundation of China.

Sixteen patients were analyzed in total. Thirteen of them had refractory ITP and had previously used two or more TPO-RAs before starting romiplostim. The results in this refractory group were strikingly poor. Eleven of the thirteen showed no response to romiplostim at all, and the remaining two exhibited only a transient partial response. In other words, not a single child in the refractory cohort achieved a complete or durable response once multiple oral TPO-RAs had already failed. The clinical burden in this group was substantial: twelve of the thirteen patients experienced bleeding episodes, eight required rescue therapy, and all thirteen ultimately switched to other drugs after romiplostim also proved ineffective.

The remaining three patients told a very different story, and the contrast is central to the study’s message. These children chose romiplostim not because other TPO-RAs had failed to work, but because of practical concerns such as potential drug interactions or liver dysfunction, which are recognized limitations of oral agents like eltrombopag. Only one of the three had previously used eltrombopag. In this selected group, two of the three patients achieved a complete response, while one showed no response. The findings suggest that romiplostim retains real value when it is used as a genuine alternative rather than as a last resort within an exhausted drug class.

On the safety front, the news was unambiguously positive. No adverse drug reactions were observed in any of the sixteen patients during the study period. This is consistent with the generally favorable tolerability profile that romiplostim has shown in pediatric populations, and it confirms that the drug itself is not the problem. The issue, the authors argue, is not whether romiplostim is safe or even whether it can work in children with ITP, but whether it can work in children whose disease has already demonstrated resistance to multiple members of its own class.

That resistance pattern carries important biological implications. TPO-RAs all converge on the same molecular target, the thrombopoietin receptor, also known as c-Mpl. If a child’s platelet production pathway remains unresponsive to two or more agents that activate this receptor through different chemical scaffolds, the likelihood that a third agent hitting the same target will succeed appears low. The study’s data give that reasoning empirical weight: within-class switching after multiple failures produced essentially no durable responses. This challenges the common clinical habit of cycling through TPO-RA options sequentially and suggests that the time and exposure spent on further within-class trials may come at the cost of delaying more appropriate therapies.

The authors conclude that romiplostim remains a safe and effective option for carefully selected pediatric ITP patients, but that children who have failed multiple oral TPO-RAs derive minimal benefit from switching to it. Instead, they recommend prioritizing alternative therapies that target immune dysregulation, the underlying mechanism of the disease, rather than continuing to push on the same thrombopoietin receptor pathway. Such alternatives could include immunomodulatory or immunosuppressive approaches that address the autoimmune attack driving platelet destruction, although the study itself does not evaluate specific alternative regimens.

As with any retrospective, single-center study, the findings come with limitations. The cohort was small, with only sixteen patients, and the refractory subgroup of thirteen, while internally consistent, limits statistical precision. Retrospective designs are also vulnerable to selection bias, since the decision to try romiplostim after multiple failures reflected real-world clinical judgment rather than a randomized protocol. Nevertheless, the near-universal failure of romiplostim in the multiply pretreated group is difficult to dismiss as chance, and the real-world sequencing that Chinese late-market conditions created gives the observation unusual relevance for clinicians everywhere who face the same decision. For families navigating refractory pediatric ITP, the study offers a clear if sobering message: after multiple oral TPO-RA failures, the next step should probably not be another drug from the same shelf.

Subject of Research: Romiplostim switching after multiple oral thrombopoietin receptor agonist failures in pediatric refractory immune thrombocytopenia

Article Title: Is switching to romiplostim still worthwhile after failure of multiple oral TPO-RAs in pediatric refractory ITP?

Article References: Is switching to romiplostim still worthwhile after failure of multiple oral TPO-RAs in pediatric refractory ITP?. (n.d.). https://doi.org/10.1007/s00277-026-07174-y

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07174-y

Keywords: immune thrombocytopenia, romiplostim, eltrombopag, avatrombopag, TPO receptor agonists, pediatric hematology, refractory ITP, switching strategy, platelet response, drug safety, retrospective study, Beijing Children's Hospital