Rosti Gianantonio, Martinelli Giovanni, Bassi Simona, Amabile Marilina, Trabacchi Elena, Giannini Barbara, Cilloni Daniela, Izzo Barbara, De Vivo Antonio, Testoni Nicoletta, Cambrin Giovanna Rege, Bonifazi Francesca, Soverini Simona, Luatti Simona, Gottardi Enrico, Alberti Daniele, Pane Fabrizio, Salvatore Francesco, Saglio Giuseppe, Baccarani Michele
Institute of Hematology and Medical Oncology L. and A. Serànoli, University of Bologna, Italy.
Blood. 2004 Mar 15;103(6):2284-90. doi: 10.1182/blood-2003-07-2575. Epub 2003 Nov 26.
Imatinib is a tyrosine-kinase inhibitor that binds to ABL proteins and induces cytogenetic remissions in patients with chronic myeloid leukemia (CML). In these patients measuring response by molecular techniques is clearly required. We determined the cytogenetic and molecular response (CgR, MR) to imatinib in 191 patients with late chronic-phase Philadelphia-positive (Ph+) CML, previously treated with interferon alpha. MR was assessed with real-time quantitative (TaqMan) reverse transcription-polymerase chain reaction and was expressed as the ratio between BCR/ABL and beta 2-microglobulin x 100, the lowest level of detectability of the method being 0.00001. A complete CgR (CCgR) was achieved in 85 (44%) of 191 patients and was maintained for 2 years in 67 (79%) of 85 patients. A reduction of the transcript level of more than 2 logs was achieved in all but 9 patients with CCgR versus none of 23 with partial CgR. In the CCgRs the median value of the MR was 0.0008 after 12 months and 0.0001 after 24 months, with the transcript level undetectable in 22 cases. We conclude that in CCgRs the degree of MR may vary from 2 to more than 4 logs, and that there is a progressive decrease of transcript level by time. Only 1 of 22 negative cases has had a relapse as yet.
