Low-dose combination chemotherapy for acute myeloid leukemia in elderly patients: a novel approach

Importance of prognostic stratification via gene mutation analysis in elderly patients with acute myelogenous leukemia

INTRODUCTION

Acute myelogenous leukemia (AML) in elderly patients is associated with an increased incidence of complications and treatment-related toxicity because of the frequency of comorbid disease and age-related deterioration in organ function. Despite advances in AML treatment in recent years, elderly patients have experienced limited benefit, and their outcomes remain poor. This study aimed to perform a comprehensive gene mutation analysis in elderly AML patients and identify gene mutations that could serve as prognostic factors.

METHODS

An analysis of gene mutations was performed for 281 AML patients, including 98 elderly patients aged 65 years or above.

RESULTS

Compared to younger AML patients, elderly patients showed a higher frequency of the following gene mutations: TP53 (P = 0.026), PTPN11 (P = 0.006), RUNX1 (P = 0.024), TET2 (P = 0.002), and ASXL1 (P = 0.023). The complete remission rate was significantly lower in DNMT3A mutation-positive cases (4.26%, P = 0.011) and TP53 mutation-positive cases (2.13%, P = 0.031) than in negative cases. The overall survival rate was significantly poorer in cases with FLT3-ITD (P = 0.003), DNMT3A (P = 0.033), or TP53 mutation (P < 0.001). Conversely, cases with PTPN11 mutation (P = 0.014) had a significantly more favorable prognosis. In multivariate analysis, FLT3-ITD (P = 0.011) and TP53 mutation positivity (P = 0.002) were independent poor prognostic factors, as were a performance status of 3 or above (P < 0.001) and poor cytogenetic prognosis (P = 0.001). In contrast, PTPN11 mutation positivity (P = 0.023) was an independent favorable prognosis factor.

CONCLUSION

Analysis of gene mutations in elderly AML patients is very important, not only for establishing prognosis, but also for introducing appropriate molecular-targeted treatments.

Flexible low-intensity combination chemotherapy for elderly patients with acute myeloid leukaemia: a multicentre, phase II study

OBJECTIVE

To evaluate the efficacy of a flexible low-intensity combination chemotherapy (FLICC) protocol in a multicentre, phase II study of elderly patients with acute myeloid leukaemia (AML).

METHOD

Twenty-five patients aged 61-78 years (median 70 years) with de novo (n = 17) or secondary (n = 8) AML (cytogenetic risk: favourable 2, intermediate 18, adverse 2, unknown 3) from eight Australian centres were enrolled. Treatment comprised mitoxantrone 6 mg/m(2) intravenously daily for 3 days, cytarabine 10mg/m(2) subcutaneously every 12 hours for 7-14 days and etoposide 100mg orally for 7-14 days.

RESULTS

The treatment was generally well tolerated, and 13 patients (52%) achieved a complete remission (CR). One patient achieved a partial remission but died on day 28 due to pneumonia. Five patients (20%) had no response, whilst six (24%) died on or before day 30 and so were not evaluable. The median overall survival (OS) was 6.5 months, and the median remission duration was 7.7 months. Estimated 1-year survival was 32%, but patients achieving CR had an estimated 1-year survival of 64%, whereas none in the non-CR group survived to 1 year. Two of the CR patients have survived beyond 2 years. OS was significantly shorter in the adverse cytogenetic risk group of patients compared with the favourable- and intermediate-risk groups, with the rates of death relative to the adverse group being 0.02 and 0.08 in the favourable- and intermediate-risk groups, respectively. There was no significant association between CR rate and pre-existing myelodysplasia or the presence of multilineage dysplasia. The median durations of significant neutropenia (<0.5 x 10(9)/L) and thrombocytopenia (<20 x10(9)/L) with the first course of treatment in the 19 evaluable patients were 19 days (range 12-26) and 11 days (range 1-25), respectively. The median duration of stay in the hospital was 27 days (range 14-42). These values were much shorter for the second course of treatment: 6 days, 5 days and 15 days, respectively.

CONCLUSION

The findings of this multicentre, phase II study validate the previously reported single-institution experience with the FLICC protocol in elderly patients with AML. The clinical outcome with this protocol is comparable to those reported with more aggressive anti-leukaemia protocols.

Flexible low-intensity combination chemotherapy for elderly patients with acute myeloid leukemia

Twenty-five patients aged 57 to 88 years (median, 70 years) with acute myeloid leukemia were treated with a flexible low-intensity treatment regimen comprising mitozantrone (mitoxantrone) 6 mg/m2 administered by intravenous infusion x3 days, cytarabine 10 mg/m2 subcutaneously every 12 hours x7 to 14 days, and etoposide 100 mg orally x7 to 14 days. Seventeen of these patients had a preexisting myelodysplastic syndrome. The clinical response was correlated to the results of cytogenetic studies (23 patients) and of viability studies of leukemic blasts (7 patients). Eleven of the 25 patients achieved complete remission (CR), 8 achieved partial remission (PR), and 4 showed no response. There was 1 toxic death, and 1 patient died soon (1 week) after presentation. Treatment was well tolerated. Although myelotoxicity occurred regularly, the recovery time was < or = 3 weeks for most of the responding patients. Duration of survival for patients who had CR has ranged from 4+ to 43+ months and for patients who had PR, 3 to 16 months. Irrespective of the remission status (CR or PR), responding patients with favorable (n = 1) or intermediate (n = 10) cytogenetic findings had a significantly better survival time (median, 14 months) than did those with unfavorable (n = 7) cytogenetic findings (median, 5 months). In vitro studies showed a progressive reduction in the number of circulating blasts. The number of viable blasts 3 days after initiation of therapy appeared to give an early indication of clinical response. Treatment with a flexible low-intensity protocol seems to achieve results comparable with those reported for intensive antileukemia therapy and has much less toxicity.

Acute myeloid leukemia in the elderly: biology and therapeutic strategies

Age represents one of the most important adverse prognostic factors in acute myeloid leukemia (AML). The therapeutic results for patients older than 60 years accrued into clinical trials of intensive chemotherapy are largely unsatisfactory (complete remission rates rarely superior to 50-60%; median relapse-free survival usually less than 12 months). Because only 30-40% of elderly patients are actually entered into these trials, the overall failure of current treatments appear even more disappointing when considered in the context of the whole population of older individuals with AML. This appears primarily due to intrinsic differences in the biology of leukemia itself and to host-related factors (i.e. reduced tolerance to chemotherapy and comorbidity). AMLs of older subjects display several biological overlaps with secondary AMLs including multilineage involvement, phenotype, unfavorable cytogenetics and elevated activity of multidrug resistance genes. The clinical application of biologically-based prognostic factors may enable to separate patients who may actually benefit from aggressive chemotherapy from those who should be offered attenuated/palliative treatments or enrolled upfront into experimental trials of new drugs or biologic/immunologic treatments. This may hopefully result in a 'risk-adapted' strategy aimed at improving disease free survival and/or quality of life for patients with differing risk profiles.

Acute myelogenous leukemia and aging. Clinical interactions

Effective treatment of the elderly patient with AML remains a challenging task. Acute myelogenous leukemia is clearly a different disease in the elderly than in the young, for many reasons, both clinical and biologic, which contribute to the worse prognosis in the elderly. The elderly, as a group, have been underrepresented in clinical trials. Several important prognostic variables have been identified and described, however, that can help the physician select the appropriate treatment for any individual patient. Age itself should not preclude an attempt at therapy, especially for AML, which progresses very rapidly in the absence of treatment. After careful analysis of prognostic factors, in any individual patient, however, the outlook may be so poor that it may be desirable to withhold treatment. With a better understanding of the pathophysiology of AML in the elderly, more targeted and less toxic treatment regimens will become available. At present, however, clinicians must use an improved understanding of the disease to predict its behavior in an individual patient, so that the currently available treatment modalities are used most prudently.