WEDNESDAY, Sept. 23 (HealthDay News) -- Patients with acute myeloid leukemia (AML), take note: A new standard of care is emerging -- at least for those younger than 50, or between 60 and 65.
That's the take-home message of a pair of studies published Wednesday in the New England Journal of Medicine. Two research teams -- the U.S.-based Eastern Cooperative Oncology Group (ECOG) and a team of scientists in the Netherlands, Belgium, Germany and Switzerland -- studied almost 1,500 patients and independently reported higher rates of complete remission and overall survival in those who received high doses of the chemo drug daunorubicin, compared to those who receive the standard dose.
Though those benefits were mostly limited to specific subsets of patients -- those younger than 50 or between 60 and 65, who had so-called "favorable" or "intermediate" genetic profiles -- they also came without any apparent increase in serious side effects.
In essence, said Dr. Hugo Fernandez of the Moffitt Cancer Center and Research Institute in Tampa, Fla., the lead author on the U.S. study, the data suggest that oncologists have nothing to lose in using the high-dose regimen, 90 mg per square meter of body surface area compared to a standard 45 mg per square meter. That's because AML must be treated aggressively, yet it can take days for genetic analyses to come back from the lab.
"The bottom line is survival," Fernandez said. "We achieved it without great cost to the patients, and without any new fancy drugs, either. This wasn't reinventing the wheel; it was using the drugs optimally. We finally got the right dose."
In an editorial accompanying the two studies, Drs. Herve Dombret and Claude Gardin from Paris, wrote, "Do we have a new standard of care in AML? The lack of an increase in toxic effects and the benefit in overall survival strongly argue for incorporating high-dose daunorubicin into the initial treatment of younger patients with AML, at least for those with favorable- and intermediate-risk cytogenetic profiles, unless an increased rate of toxic effects is feared when high-dose daunorubicin is used in association with new agents, such as FLT3 inhibitors, currently in ongoing trials."
According to the Leukemia & Lymphoma Society, 13,290 Americans were "expected to be diagnosed" with AML last year. Half of all AML patients are older than 65.
Treatment usually includes a so-called "7+3" induction regimen, in which patients are given cytarabine for seven days and daunorubicin (or a related drug, such as idarubicin) for three. The daunorubicin is typically administered at 45 mg per square meter of body surface area, yet anecdotal evidence suggested higher doses might be more effective, Fernandez said.
The two research teams set out to determine whether that was actually the case -- in patients younger than age 60 in the ECOG trial, or older than age 60 in the European trial.
Rates of complete remission and overall survival improved in both studies. Yet the effects were most pronounced when the researchers focused on specific subgroups, rather than the entire study population.
For instance, in the ECOG study overall, complete remission rates jumped from 57.3 percent for the standard treatment group, to 70.6 percent for the high-dose group, while median survival improved from 15.7 months to 23.7. For those patients younger than 50, survival improved from a median of 19 months, to 34.3 months. But no benefit was seen for patients 50 or older.
Similarly, survival improved from 20.7 to 34.3 months for patients with "favorable" or "intermediate" genetic profiles, but no benefit at all was observed in patients with an "unfavorable" profile.
In the European trial, overall complete remission rates rose in the high-dose group from 54 percent to 64 percent, with no overall improvement in two-year overall survival. Yet when looking only at patients aged 60 to 65, remission improved from 51 percent to 73 percent, while two-year survival improved from 23 percent to 38 percent.
"I think the take-home message is that the outcomes seem to be sufficiently improved, at least in patients less than 50, and aged 60 and 65, that this is a reasonable standard of care," said Dr. Michael Millenson, director of the hematology service at the Fox Chase Cancer Center in Philadelphia. He added, "Since we don't necessarily have all the cytogenetic information back when we have to make a decision about dosing, I think the reassuring thing is that there didn't seem to be excessive toxic side effects."
Dr. Anthony Stein, of the City of Hope in Duarte, Calif., who sees "at least two new AML patients per week," uses idarubicin rather than daunorubicin. But, he said, "based on these two papers, it didn't look like using the higher dose led to more toxicity, so if I were going to use daunorubicin, I would use the higher dose."
Dr. Barton Kamen, chief medical officer at the Leukemia & Lymphoma Society, said the studies highlight the heterogeneity of AML and the power of "personalized medicine" -- as well as the need for more research.
"To me the tagline is, AML is lots of different diseases," Kamen said. "And we need to know as much as we can of the patient and the disease to treat them. This is a spectacular example of that."
"But," he added, "they still have a lot of work to do."
Kamen doesn't advocate giving high-dose daunorubicin to all patients, only those who are likely to benefit. "There are short- and long-term side effects we don't know yet," he said. Of particular concern, daunorubicin can damage the heart.
Indeed, Fernandez noted there are "nay-sayers" in the oncology community who suggest that, five or six years down the road, patients might be better off had they received the lower dose. "But my retort is, with the high dose, they are more likely to be alive."
For more information on AML, visit the Leukemia & Lymphoma Society.
SOURCES: Hugo F. Fernandez, M.D., associate member and associate chair, department of blood and marrow transplantation, Moffitt Cancer Center and Research Institute, Tampa, Fla.; Anthony S. Stein, M.D., professor, hematology and hematopoietic cell transplantation, associate member, hematologic malignancies program, Comprehensive Cancer Center, City of Hope, Duarte, Calif.; Barton A. Kamen, M.D., Ph.D., chief medical officer, Leukemia & Lymphoma Society; Michael Millenson, M.D., director, Hematology Service, Fox Chase Cancer Center, Philadelphia; Sept. 24, 2009, New England Journal of Medicine