The Spectrum of FIP1L1-PDGFRA-Associated Chronic Eosinophilic Leukemia: New Insights Based on a Survey of 44 Cases

• Published in: Medicine (Baltimore) 2013-09, Vol.92 (5), p.e1-e9
• Main Authors: Legrand, Fanny, Renneville, Aline, MacIntyre, Elizabeth, Mastrilli, Samuel, Ackermann, Felix, Cayuela, Jean Michel, Rousselot, Philippe, Schmidt-Tanguy, Aline, Fain, Olivier, Michel, Marc, de Jaureguiberry, Jean-Pierre, Hatron, Pierre-Yves, Cony-Makhoul, Pascale, Lefranc, Didier, Sène, Damien, Cottin, Vincent, Hamidou, Mohamed, Lidove, Olivier, Baruchel, André, Dubucquoi, Sylvain, Bletry, Olivier, Preudhomme, Claude, Capron, Monique, Prin, Lionel, Kahn, Jean Emmanuel
• Format: Article
• Language: English
• Subjects: Original Study
• ISSN: 0025-7974; 1536-5964
• DOI: 10.1097/MD.0b013e3182a71eba

Imatinib is the treatment of choice for FIP1L1/PDGFRA (F/P)-associated chronic eosinophilic leukemia (F/P CEL), but its optimal dosing, duration, and possibility of discontinuation are still a matter of debate. A retrospective multicenter study was conducted with 44 F/P CEL patients identified in the French Eosinophil Network and treated with imatinib. The most frequently involved systems were skin (57%), spleen (52%), and lung (45%), and eosinophilic heart disease was observed in 15 patients (34%). Complete hematologic response (CHR) was obtained in all patients, and complete molecular response (CMR) in 95% of patients (average initial imatinib dose, 165 mg/d). For 29 patients the imatinib dose was tapered with a maintenance dose of 58 mg/d (±34 mg/d), allowing sustained CHR and CMR. None of the patients developed resistance during a median follow-up of 52.3 months (range, 1.4-97.4 mo). Imatinib was stopped in 11 patients; 6 of the patients subsequently relapsed, but 5 remained in persistent CHR or CMR (range, 9-88 mo). These results confirm that an initial low-dose regimen of imatinib (100 mg/d) followed by a lower maintenance dose can be efficient for obtaining long-term CHR and CMR. Our data also suggest that imatinib can be stopped in some patients without molecular relapse.