Efficacy and safety of ruxolitinib in patients with myelofibrosis and low platelet count (50 x 109/L to < 100 x 109/L) at baseline: the final analysis of EXPAND

Paola Guglielmelli*, Jean-Jacques Kiladjian, Alessandro M. Vannucchi, Minghui Duan, Haitao Meng, Ling Pan, Guangsheng He, Srdan Verstovsek, Francoise Boyer, Fiorenza Barraco, Dietger Niederwieser, Ester Pungolino, Anna Marina Liberati, Claire Harrison, Pantelia Roussou, Monika Wroclawska, Divyadeep Karumanchi, Karen Sinclair, Peter A. W. Te Boekhorst, Heinz Gisslinger

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Background: Thrombocytopenia is a common feature of myelofibrosis (MF), a myeloproliferative neoplasm driven by dysregulated JAK/STAT signaling; however, pivotal trials assessing the efficacy of ruxolitinib (a JAK1/2 inhibitor) excluded MF patients with low platelet counts (<100 × 10 9/L). Objectives: Determination of the maximum safe starting dose (MSSD) of ruxolitinib was the primary endpoint, with long-term safety and efficacy as secondary and exploratory endpoints, respectively. Design: EXPAND (NCT01317875) was a phase 1b, open-label, ruxolitinib dose-finding study in patients with MF and low platelet counts (50 to <100 × 10 9/L). Methods: Patients were stratified according to baseline platelet count into stratum 1 (S1, 75 to <100 × 10 9/L) or stratum 2 (S2, 50 to <75 × 10 9/L). Previous analyses established the MSSD at 10 mg twice daily (bid); long-term results are reported here. Results: Of 69 enrolled patients, 38 received ruxolitinib at the MSSD (S1, n = 20; S2, n = 18) and are the focus of this analysis. The incidence of adverse events was consistent with the known safety profile of ruxolitinib, with thrombocytopenia (S1, 50%; S2, 78%) and anemia (S1, 55%; S2, 44%) the most frequently reported adverse events and no new or unexpected safety signals. Substantial clinical benefits were observed for patients in both strata: 50% (10/20) and 67% (12/18) of patients in S1 and S2, respectively, achieved a spleen response (defined as ⩾50% reduction in spleen length from baseline) at any time during the study. Conclusion: The final safety and efficacy results from EXPAND support the use of a 10 mg bid starting dose of ruxolitinib in patients with MF and platelet counts 50 to <100 × 10 9/L. Registration: ClinicalTrials.gov NCT01317875.

Original languageEnglish
Number of pages13
JournalTherapeutic Advances in Hematology
Publication statusPublished - 10 Sept 2022

Bibliographical note

Funding Information:
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was funded by Novartis Pharmaceuticals.

Publisher Copyright:
© The Author(s), 2022.


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