b2a2 Type bcr-abl Transcript Chronic Myelogenous Leukemia (CML) Patients in Chronic Phase (CP) on Glivec Achieve Complete Cytogenetic Remission (CCyR) Earlier Than Those with b3a2.

There are few data on different biological significance of b2a2 and b3a2 transcripts. The main one is thrombocytosis in b3a2 CML patients (R.A.Perego e.a.,2000), probably associated with coexpression of m-bcr-abl (T.Liu e.a.,2006). Noteworthy that the level of transcripts in primary CML patients did not differ(Rodrigues J. e.a.,2005). That was the reason for evaluating Glivec efficacy in CP CML patients with bcr-abl trabscripts- b2a2 and b3a2.

Patients and Methods. 97 Ph+, CP CML patients were studied. They received Glivec either as front line therapy or after resistance to preceeding therapy. Analysis of b3a2 and b2a2 transcripts was performed in 27 of them. Cytogenetics was performed routine technology with G-banding. Statitics: Kaplan-Meier survival analysis and Cox regression model were used.

Results. The median time to CCyR in whole cohort of patients was 320 days. Of 27 bcr-abl studied patients, 9 had b2a2 and 18 b3a3 transcripts. They did not differ in age, duration of the disease and Sokal Score. Median time to CCyR in b2a2 patients was 172 days and 362 in b3a2 patients(p=.0001). Time to CCyR was shorter in b2a2 patients(p=.003) and insignificantly longer in b3a2 patients when compared to the whole cohort of studied patients. Cox analysis revealed that type of transcripts is independant prognostic factor, including platelet level and spleen size. Difference was more pronounced in patients with front line Glivec therapy.

Conclusion. b2a2 transcript is independent prognostic marker for early achievement of CCyR on Glivec therapy.