Improved survival in AML with higher anthracycline doses

Improved survival in AML with higher anthracycline doses



Younger patients with acute myeloid leukemia (AML) that receive higher doses of anthracyclines during induction chemotherapy are reported to have better complete remission rates in most studies. As of yet, studies have failed to show an improved surivival when compared to the standard doses of the “7 and 3” regimen. This article reviews the results of a new randomized controlled trial exploring the effects of higher doses of anthracyclines on overall survival.

With the exception of the use of all trans-retinoic acid (ATRA) for patients with acute pro-myelocytic leukemia (APL), relatively few changes in the therapy of acute myeloid leukemia (AML) have been made since the introduction of the so-called “7 and 3” regimen in 1973.^{1, 2} The regimen is made up of 3 daily doses of daunorubicin at a dose of 45 mg/m2 combined with cytarabine for seven continuous daily doses at 100 mg/m2.^{1, 2}

The outcome to current therapy is suboptimal with only 60-70% of patients achieving their first complete remission. The median survival of patients who achieve remission is 12-24 months and the five year survival is achieved in only 20% of those patients.³ Attempts to find a superior alternative or improve the 7 and 3 induction regimen have been disappointing.^{4, 5} Both, the intensification of cytarabine dose^6-8 and the addition of other drugs, have failed to improve outcome when compared to “7 and 3”.⁹

That all changed this week, with the publication of the first conclusive evidence for better overall survival in patients receiving higher doses of daunorubicin (90 mg/m2) compared to the conventional dose (45 mg/m2) regimen. The Eastern Cooperative Oncology Group (ECOG) study, which appears this week in the New England Journal of Medicine,¹⁰ assigned 657 patients between the ages of 17 and 60 years with newly diagnosed AML to receive either the 7 and 3 induction regimen with conventional dose of  daunorubicin versus the higher dose. Those that achieved a complete remission were then given post remission therapy according to their risk stratification as well as the availability of an HLA matched sibling. Patients with unfavorable or intermediate risk profile were offered allogeneic transplant if they had an HLA matched sibling.^{11, 12} The remainder were offered high dose cytarabine with or without gemtuzumab ozgamicin, followed by an autologous transplant.¹³

An intention to treat analysis, with a median follow up of 25.2 months, revealed that 90 mg/m2 daunorubicin resulted in higher complete remission rates (70.6% vs. 57.3%, P=0.001) as well as improved median survival (23.7 vs. 15.7 months, P=0.003).

Interestingly, the rates of serious (grade 3 to 5) adverse events were similar in the two groups. Serious cardiac toxicity was observed in 7.2% in the standard dose arm compared to 7.9% in the high dose arm. A reduced left ventricular ejection fraction was observed in 1.3% of patients in the high dose group and none of the standard regimen group. The rate of treatment related mortality was 4.5% in the standard arm compared to 5.5% in the high dose arm (P=0.60). The most common cause of death was from infections and pulmonary failure.

Results

For those patients with a favorable cytogenetic profile that received the high dose, the median survival had not been reached at the time of the final analysis (median follow up of 25.2 months); thus, exceeding the current median survival of 12-24 months in patients who achieve remission.³ The largest difference was seen in those with intermediate risk who received the daunorubicin 90 mg/m2. Patients with unfavorable cytogenetic profile, however, did not experience any benefit from higher doses.

Conclusion

Patients with low and intermediate risk de novo AML should be offered 7 and 3 induction therapy with daunorubicin dose intensification at 90 mg/m2. This is both safe and effective in these patients but not associated with any benefit in patients with poor prognostic features. However, as the authors note, it is not yet clear what the optimal dose of intensification is. Whether 90 mg/m2 is better than 60 mg/m2, requires further study.

Conflict of interest statement

No financial conflicts or disclosures to report.

CITE THIS ARTICLE:
Tamer M. Fouad, M.D.. Improved survival in AML with higher anthracycline doses. Doctors Lounge Website. Available at: http://www.doctorslounge.com/index.php/articles/page/300. Accessed April 01 2012.