Imatinib in advanced chordoma : a retrospective case series analysis

Introduction Imatinib showed activity in 50 chordoma patients treated within a Phase II study. In that study, 70% of patients remained with stable disease (SD), median progression free survival (PFS) was 9 months and median overall survival (OS) was 34 months. We now report on a retrospective series of PDGFB/PDGFRB positive advanced chordoma patients treated with imatinib as a single agent within a compassionate-use programme at Istituto Nazionale Tumori, Milan, Italy (INT) between August 2002 and November 2010, when the programme was closed. Methods 48 patients were consecutively treated with imatinib 800 mg/d. All patients had inoperable and progressive disease before starting imatinib. Demographics, treatment duration, toxicity and response rate by Response Evaluation Criteria in Solid Tumors (RECIST) were retrospectively recorded. Results The median duration of therapy was 7 months (1-46.5). No patient is on therapy at present. 46 patients were evaluable for response. No partial responses were detected. Best response was: stable disease 34 (74%), progressive disease 12 (26%). At a median follow-up of 24.5 months (0.5-117), median PFS was 9.9 months (95% confidence interval (CI) 6.7-13). Eight patients (16.5%) remained on therapy >18 months and 10 patients (21%) remained progression-free >18 months. Median OS was 30 months (95% CI 20-40), with 24 (50%) patients dead at the time of the present analysis. Conclusions We confirm the activity of imatinib in locally advanced and metastatic chordoma, in terms of >70% tumour growth arrest in previously progressive patients. Median duration of response lasted almost 10 months, with >20% of patients progression-free at 18+ months.