A Population (Registry) Based Analysis of the Impact of Bcr-Abl Specific Tyrosine Kinase Inhibition on Survival after Diagnosis of Philadelphia Chromosome Positive Chronic Myelogenous Leukemia..

Specific tyrosine kinase inhibition (TKI) of the bcr-abl fusion protein in Philadelphia chromosome positive chronic myelogenous leukemia (CML) was introduced into general use in 2000 after a plenary abstract presentation to ASH in December 1999. Here we report the impact of the use of TKI on survival of all patients with CML in a total population based registry in the province of Alberta in Canada where BMT has been in use since 1980, α interferon +/− cytarabine since 1990 and TKI since 2000. All therapies have been fully funded by the public health care system in Alberta. Alberta’s population in 2000 was 2.97 million.

Prior to 2000, allogeneic stem cell transplant (BMT) was the only curative therapy available but its application was limited to a minority of patients with CML. Alpha interferon induced a cytogenetic remission in some CML and alpha interferon plus cytarabine prolonged survival in CML.

A 5 year survival for CML (1980–89) of 40% is consistent with published data. The 48% 5 year survival for CML (1990–99) reflects the benefit of interferon. The 5 year survival of acute myelogenous leukemia (AML) in Alberta is provided for comparison to reflect general improvement in care.

The proportion of AML patients who had a BMT did not significantly change while there was a significant reduction in numbers of CML transplanted in 2000–06. Transplant status did not significantly affect outcome in CML patients with 75% of non-BMT and 84% of BMT patients still alive at 5 years (p=0.08). In contrast, transplant status was statistically significant in AML, with 5 year survival of 49% in those treated with BMT, compared to 17% of those not transplanted (p<0.0001).

The results of this study show that TKI therapy (primarily imatinib) has had a major impact on the outcome of CML treatment in the province of Alberta. Long term survival, >80%, has been achieved and it appears that almost all of these patients can look forward to a normal life expectancy without the need for BMT.