This is what a ‘game changing’ cancer therapy looks like

Life expectancy in patients with chronic myeloid leukemia has soared to a level almost equal to that of the general population, according to a Swedish study quantifying the life-saving impact of Gleevec, the targeted therapy ushered from lab bench to clinical success by Brian Druker, M.D., director of the OHSU Knight Cancer Institute.

Figure: Gleevec binds to the kinase domain of the mutant enzyme BCR-ABL1

Patients of all ages diagnosed with CML in 2013 will, on average, lose less than three years of life as a result of CML, Hannah Bower and colleagues report in the Journal of Clinical Oncology.

The researchers considered the lifespans of 2,662 patients recorded as having CML in the Swedish Cancer Registry from 1973 to 2013. They used statistical modeling to estimate changes in life expectancy and also changes in the number of years of life lost as a result of a cancer diagnosis.

A 55-year-old woman diagnosed with CML in 1990 could expect to lose nearly 24 years of life as a result of the cancer. By 2010, the loss in expectation of life was 2.9 years, the researchers calculated.

years of life expectancy at age 55 for women and men diagnosed with CML compared with the general population from 1980 to 2010.
Years of life expectancy at age 55 for women and men diagnosed with CML compared with the general population from 1980 to 2010. (OHSU/Joe Rojas-Burke)

Even before the introduction of Gleevec, the Swedish data show notable improvements in life expectancy for people with CML. The use of allogeneic stem cell transplantation, interferon alfa, more precise diagnostics, and a more structured approach in treating and monitoring patients are plausible explanations, the researchers said.

After FDA approval in 2001, Gleevec quickly became the gold standard for first-line treatment of CML. It is a tyrosine kinase inhibitor that specifically targets a mutant protein, BCR-ABL1, that is a driver of malignant transformation in CML. Second- and third-generation TKIs have continued to better outcomes by providing effective therapy when CML develops resistance to Gleevec.

The researchers noted, however, that TKIs have been associated with cardiovascular adverse effects and increased incidence of other cancers that could somewhat offset the survival gains. Thus, the life expectancy of patients with CML may never equal that of the general population.

“Even so,” the researchers said, “the life expectancy of patients with CML was within 3 years of the life expectancy of the general population for diagnoses in 2010, which can be seen as a great success of CML treatment.”

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Life Expectancy of Patients With Chronic Myeloid Leukemia Approaches the Life Expectancy of the General Population, by Hannah Bower, Magnus Björkholm, Paul W. Dickman, Martin Höglund, Paul C. Lambert and Therese M.-L. Andersson, Journal of Clinical Oncology, June 20, 2016.