Related Experiment Video
Updated: May 24, 2026
Robotic Duodenal Sleeve Resection for Gastrointestinal Stromal Tumor with Rare Exon 8 KIT Mutation Following Neoadjuvant Imatinib
Published on: April 3, 2026
Phase II study of imatinib in advanced chordoma
Silvia Stacchiotti1, Alessandra Longhi, Virginia Ferraresi
1Fondazione Istitutodi Ricovero e Cura a Carattere Scientifico Istituto Nazionale Tumori, Milan, Italy. silvia.stacchiotti@istitutotumori.mi.it
Purpose:
To explore the antitumor activity of imatinib in patients with advanced platelet-derived growth factor β (PDGFB)/PDGF receptor β (PDGFRB)-positive chordomas.
Patients And Methods:
In a collaborative Italian-Swiss, prospective, phase II clinical study conducted from November 2004 through April 2006, 56 patients with advanced PDGFB and/or PDGFRB chordoma received 800 mg/d of imatinib until progression. The primary end point was the overall tumor response rate (ORR), defined by RECIST. Secondary, exploratory end points included tissue response (ie, changes in tumor density or signal intensity/contrast enhancement, and/or [18F]-fluorodeoxyglucose positron emission tomography [PET] uptake), overall survival, progression-free survival (PFS), and pain score.
Results:
Among 50 patients evaluable by RECIST, the best response was one partial response (PR) obtained at 6 months (ORR, 2%). There were 35 patients with stable disease (SD, 70%) and a 64% clinical benefit rate (ie, RECIST complete response + PR + SD ≥ 6 months). A minor dimensional response (< 20%) was detected in nine patients. A maximum standard uptake value decrease ≥ 25% was observed in 10 (39%) of 26 patients evaluable for PET response at 3 months. Changes in the Brief Pain Inventory score were consistent with the response assessment. Median PFS (intention-to-treat population, 56 patients) was 9 months. No unexpected toxicities were observed.
Conclusion:
This is the largest phase II study in chordoma to date. It confirms anecdotal evidence that imatinib has antitumor activity in this orphan disease, and therefore, it is worth further investigation.
