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The Desmoid Tumor Research Foundation

December 2023

Regorafenib in advanced solitary fibrous tumour: Results from an exploratory phase II clinical study

Author Information

Silvia Stacchiotti 1, Giacomo Giulio Baldi 2, Anna Maria Frezza 3, Carlo Morosi 4, Francesca Gabriella Greco 4, Paola Collini 5, Marta Barisella 5, Gian Paolo Dagrada 6, Nadia Zaffaroni 7, Sandro Pasquali 7, Alessandro Gronchi 8, Paul Huang 9, Matilde Ingrosso 3, Gabriele Tinè 10, Rosalba Miceli 10, Paolo Giovanni Casali 3

1Medical Oncology Unit 2, Cancer Medicine Department, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Nazionale Tumori, Milan, Italy. Electronic address: silvia.stacchiotti@istitutotumori.mi.it. 2Department of Medical Oncology, 'Santo Stefano' Hospital, Prato, Italy. 3Medical Oncology Unit 2, Cancer Medicine Department, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Nazionale Tumori, Milan, Italy. 4Department of Radiology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 5Soft Tissue Tumor Pathology Unit, Advanced Diagnostics Department, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 6Department of Pathology and Laboratory Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 7Molecular Pharmacology Unit, Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 8Sarcoma Unit, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 9Division of Molecular Pathology, Institute of Cancer Research, London, UK. 10Unit of Biostatistics for Clinical Research, Department Epidemiology and Data Science, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

Publication

Eur J Cancer

Summary

Background: To investigate the activity of regorafenib in advanced solitary fibrous tumour (SFT). Methods: An Italian monocentric investigator-initiated exploratory single-arm Phase II trial was conducted of regorafenib in adult patients with advanced and progressive SFT, until progression or limiting toxicity. Prior treatment with antiangiogenics was allowed. Primary and secondary end-points were: overall response rate (ORR) by Choi criteria, and ORR by RECIST, progression-free survival (PFS), overall survival (OS). Results: From January 2016 to February 2021, 18 patients were enroled [malignant-SFT = 13; dedifferentiated-SFT (D-SFT) = 4; typical-SFT (T-SFT) = 1]. Fourteen patients were pre-treated, in 12 cases with antiangiogenics (median [m-] lines of treatment = 3). Sixteen patients were evaluable for response (one screening failure; one early discontinuation). Six/16 (35.2%) required a definitive dose reduction. ORR by Choi was 37.5% (95% CI: 15.2-64.6), with 6/16 (37.5%) partial responses (PR), 6/16 (37.5%) stable disease (SD) and 4/16 (25%) progressions; 5/6 responses occurred in patients pre-treated with antiangiogenics. No responses were detected in D-SFT. Best RECIST responses were: 1/16 (6.2%) PR, 12/16 (75%) SD, 3/16 (18.8%) progressions. At 48.4 month m-FU, m-PFS by Choi was 4.7 (inter-quartile range: 2.4-13.1) months, with 31.2% patients progression-free at 1 year. Conclusion: Regorafenib showed activity in SFT, with 30% patients free-from-progression at one year. Responses were observed also in patients pretreated and refractory to another antiangiogenic agents. However, ORR and m-PFS were lower than reported with other antiangiogenics, and this was possibly due to discrepancies in the patient population and the high-rate of dose reductions.

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