Dec 9, 2002
Gleevec, the new anti-leukemia drug from Novartis Pharmaceuticals, achieves a marked improvement in survival even for patients in the accelerated phase of chronic myeloid leukemia (CML), according to a study to be presented on Monday afternoon, Dec. 9, at the meeting of the American Society of Hematology (ASH) in Philadelphia.
Comments Dr. Richard T. Silver, a professor at Weill Cornell Medical College and Attending Physician at NewYork-Presbyterian Hospital Weill Cornell Medical Center, who will present the findings: "Until now, the story of this disease has been like the story of Sisyphus who was condemned by the gods to roll a great stone up a mountain for all eternity. Gleevec has brought us a lot closer to the mountaintop than we've ever been."
For 181 patients with accelerated disease who were treated with an initial dose of 600 milligrams per day, the two-year survival rate from the beginning of Gleevec treatment was about 66 percent, and the three-year rate was about 60 percent. At the latter point, about two-thirds of the survivors had not moved beyond the acceleration phase to what is called a blast crisis.
CML can remain in a chronic phase for many years, but, when the disease enters the accelerated phase, it commonly leads to a terminal blast crisis within a matter of months. It is then that the system can be overwhelmed by a rampant proliferation of immature white cells. Results with 600 milligrams were substantially better than with 400 milligrams, without an increase in side effects. Patients who started out with the lower dose had a survival rate of about 44 percent for two years and 30 percent for three years.
The study, which has 21 co-authors, concludes that Gleevec "at an initial dose of 600 milligrams significantly improves survival and shows significant superiority to the 400-milligram dose."
Two hundred thirty-five patients were enrolled in the trial at 18 centers in Europe and the United States between August 1999 and March 2000. Their disease was judged to be in the accelerated phase on the basis of any of four hematologic criteria, and this was subsequently confirmed in 181 cases based on a central review of data. The confirmed cases were about evenly divided between men and women, and the median age at enrollment was 57. Sixty-two were treated initially with 400 milligrams of Gleevec a day, and 119 were treated with 600 milligrams.
Not surprisingly, survival reflected the body's response to therapy. Among patients who had a complete hematological remission of four weeks or more—meaning an apparent complete absence of blast cells in their marrow or blood—the three-year survival rate was about 85 percent, whereas patients who had only a transitory hematological remission, or none at all, had a three-year survival rate of only about 20 percent. Overall, 72 percent of the patients had a sustained hematologic response—that is, for four weeks or more—of which the majority were complete remissions.