Treatment of Elderly Acute Myeloid Leukemia (AML) Patients with the Combination of Mitoxantrone and Cytarabine (MAC).

The value and exact type of intensive chemotherapy of unselected elderly AML patients in terms of overall survival (OS) and quality of life remains controversial. The lack of large randomized trials comparing intensive to low dose treatment or to just supportive care as well as the selection bias observed in smaller studies in AML patients over 60 years contribute significantly to the clinical dilemma. Despite recent improvements in supportive measures during cytotoxic therapy, elderly AML patients continue to exhibit lower remission rates, higher toxicity, more relapses and eventually a worse survival. The present analysis evaluates in a retrospective manner the outcome of 39 homogeneously treated AML patients >60yrs during a period of 44 months (Nov 2001 to Aug 2005). The protocol schedule included an initial course of mitoxantrone + cytarabine 3+5 (12mg/m²/d and 100mg/m² q12h respectively) followed by a second abbreviated course of mitoxantrone + cytarabine 2+5, followed by a final course of idarubicin + cytarabine + thioguanine 2+7+7 (10mg/m²/d, 100mg/m² q12h and 100mg/m²/d respectively). G-CSF at 5μg/Kg was added to all courses to accelerate hematopoietic recovery. Our patient population consisted of 22 cases of de novo AML and 17 cases of secondary AML (MDS 16, NHL 1) classified according to FAB as follows: M0 (5), M1 (4), M2 (19), M4 (3), M5 (2), M6 (5), hybrid-leukemia (1). Their median age was 70 yrs (range 63–80 yrs) and M/F ratio was 27/12. Cytogenetic analysis was performed in 33/39 cases: 6/33 cases failed to produce metaphases, 20/33 cases revealed standard risk abnormalities (seventeen normal karyotype, three trisomy 8) and 7/33 cases had poor risk abnormalities by MRC cytogenetic criteria. Leukocytosis >50X10⁹/L was noted in 6/39 and leukopenia<5X10⁹/L was noted in 19/39 patients. After a median observation period of 9 months (range 1–40) the following results are available: 19/39 (48,7%) patients entered CR (13 de novo, 7 secondary) post-course 2 and their median OS is 15,5 months (range 2–40). An additional 6/39 (15,3%) cases returned to a myelodysplastic phase without excess of blasts achieving thus partial hematological remission. The remaining 14/39 (35,8%) patients proved primary resistant and deceased after a median of 2,5 months (range 1–20) with one resistant patient surviving 20 months with on-going disease. Within the group of remitters 3/19 deceased from complications (MI, fungal infection, sepsis) before the next chemotherapy course. The remaining 11/19 remitters relapsed after a median of 7,5 months (range 1–30); nine of them deceased and two are alive as a result of salvage treatment. Finally 5/19 cases remain alive and disease-free (two interrupted after the second course).

Conclusion: Combination chemotherapy with mitoxantrone and cytarabine is well-tolerated and reasonably effective in elderly AML patients fit enough to undergo chemotherapy regardless of karyotype and antecedent blood dyscrasia. With a total response rate of 64% (CR+PR) and an induction death rate of 5,1% (2/39), the current schedule deserves further evaluation in a larger AML population. Furthermore, our data validate the improvement in survival of those patients achieving CR as suggested by other studies.