Splenectomy for Primary Immune Thrombocytopenia Revisited at the Era of Thrombopoietin Receptor Agonists: New Insights for an Old Treatment

Introduction

Although splenectomy is still considered as the most effective curative treatment for primary immune thrombocytopenia (ITP), its use has significantly declined in the last decade, especially since the emergence of thrombopoietin receptor agonist (TPO-RAs) and anti-CD20 monoclonal antibodies ^1-3. The main objective of our study was to evaluate if splenectomy was still as effective in the modern era, particularly for patients who failed to respond to TPO-RAs and rituximab. One of the secondary objectives was to assess, among patients who did not respond to or relapse after splenectomy, the pattern of response to subsequent intervention with treatments used before splenectomy and particularly TPO-RAs.

Methods

This multicentre retrospective observational study involved adults who underwent surgical splenectomy for primary ITP in France from 2011 (authorization of TPO-RAs in France) to 2020. To be included in the study, patients had to fulfil the following criteria : age ³18 years, primary ITP diagnosis defined according to the usual international criteria ². Patients with abnormal spleen histology (other than reactional lymphoid hyperplasia, white-pulp hypoplasia or red pulp hyperplasia) or yet definite secondary ITP were excluded. Response was defined according to international criteria ⁴. Sustained response was defined as the absence of ITP relapse at last visit. We performed univariable and multivariable logistic regression procedures to calculates the odds ratio associated with a sustained response.

Results

In total,185 patients, 98 (53 %) women, with median age at splenectomy of 43.3 [interquartile range 27.6-64.3] years, were included in 18 French university and general hospitals from the French reference center network. Most of the patients were splenectomised at the chronic phase of ITP (n=150, 81.1%) and only two patients had undergone surgery within 3 months after ITP onset. Of note, 100 (54.1%) and 135 (73.0%) patients received TPO-RAs and/or rituximab prior to the splenectomy, respectively. The median time of follow-up after splenectomy was 39.2 months [16.5-63.0]. Overall, 144 (77.8%) of patients had an initial response and 23 patients (12.4%) relapsed during follow-up leading to an overall rate of sustained response of 65.4%, similar to the one observed in the pre-TPO-RA's era ¹. Characteristics of patients according to the period during which occurred the splenectomy is available in Table 1.

Among the 14 patients who failed to respond to both eltrombopag and romiplostim prior to splenectomy a sustained response after splenectomy was observed in 7 (50%). Among the 13 patients who had failed after both TPO-RAs and rituximab, we observed a sustained response in 6 (46%).

In the multivariate analysis, an older age (60-75 years: OR 0,39 [0,17-0,86], p=0.02; >75 years: OR 0,28 [0,10-0,75], p=0.013) and a history of more than 4 treatment lines for ITP before splenectomy (OR 0.25 [0.08-0.66], p=0.010) were significantly associated with a lack of sustained response after splenectomy.

TPO-RAs were used for 57/64 (89.1%) patients who failed to respond to splenectomy. Among them, 21 were treated with one TPO-RA (i.e. eltrombopag or romiplostim) which was previously used before splenectomy without any efficacy and a response was observed in 13 (62%) of them.

Conclusions

In conclusion, splenectomy seems to be still a relevant option for treating adult primary ITP not responding to TPO-RAs and rituximab. Patients who fail to respond or relapse after splenectomy should be re-challenged with TPO-RAs.

1. Kojouri, K., Vesely, S. K., Terrell, D. R. & George, J. N. Splenectomy for adult patients with idiopathic thrombocytopenic purpura: a systematic review to assess long-term

2. Provan, D. et al. Updated international consensus report on the investigation and management of primary immune thrombocytopenia. Blood Adv.

3.Neunert, C. et al. American Society of Hematology 2019 guidelines for immune thrombocytopenia. Blood Adv. 3, 3829-3866 (2019).

4. Rodeghiero, F. et al. Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group. Blood 113, 2386-2393 (2009).

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