Efficacy and feasibility of cyclophosphamide combined with intermediate- dose or high-dose cytarabine for relapsed and refractory acute myeloid leukemia (AML)

Outcome of patients with relapsed or refractory acute myeloid leukemia treated with Mito-FLAG salvage chemotherapy

PURPOSE

Curative intended treatment is challenging in patients with relapsed or refractory acute myeloid leukemia (r/r AML) and associated with a dismal prognosis for long-term survival. Despite novel treatment options, the majority of patients are treated with chemotherapy-based regimens. Although widely used, little data exist on the combination of fludarabine, cytarabine, granulocyte colony stimulating factor (FLAG) and mitoxantrone as salvage strategy for r/r AML.

MATERIALS AND METHODS

Sixty-six patients receiving Mito-FLAG for r/r AML treated at a German tertiary care center between 2009 and 2019 were analyzed with regard to response rates, survival and safety profile.

RESULTS

Overall response rate was 75.8% with 56.1% of patients achieving complete remission (CR) and 19.7% partial remission (PR). After a median follow-up of 54 months, median overall survival (OS) was 13 months. Patients transitioned to allogeneic hematopoietic stem cell transplantation (alloHSCT) (75.8%) showed a significant improvement in OS with a median OS of 17 (95% CI 8.5-25.4) months vs 3 (95% CI 1.7-4.3) months (p < 0.001). 30- and 60-day mortality rates for all patients after the initial cycle of Mito-FLAG were 4.5% and 7.6%, respectively.

CONCLUSION

The Mito-FLAG salvage protocol represents an effective and feasible treatment regimen for r/r AML. Importantly, a high rate of transition to successful alloHSCT with the aim of long-term disease-free survival has been shown.

Combination of cyclophosphamide and cytarabine as induction regimen for newly diagnosed adult acute myeloid leukemia

Optimizing the induction therapy of acute myeloid leukemia (AML) may improve the remission rate and reduce the risk of relapse, thereby extend survival. Cyclophosphamide (CTX) shows benefit in treating relapsed and refractory AML patients, but it has not been reported in first-line induction regimens. To assess the efficacy and safety of CTX and moderate-dosage cytarabine (Ara-C) as induction chemotherapy in newly diagnosed adult AML, 40 patients were enrolled to receive CTX (20 mg/kg/d) for 4 consecutive days and Ara-C for 3 (1 g/m2 q12h, CA4+3) or 5 (1 g/m2 qd, CA4+5) days. With one course of induction chemotherapy, the overall response rate and the complete remission rate (CR) was 82.5% (33/40) and 77.5% (31/40), respectively. The expected 5 years overall survival and relapse-free survival was 64% in patients experienced CR and fulfilled consolidation therapy. The neutrophil and platelet recovery time were 17 (range, 10-20) days and 16.5 (range, 12-30) days in the CA4+3 group, faster than that of 20 (16-36) days and 20 (14-36) days in the CA4+5 group (P = .006 and P = .006). The cyclophosphamide and cytarabine (CA) regimen was generally safe and had reversible adverse effects. The patients who failed to respond to the CA regimen did not benefit from a second course of other traditional induction chemotherapy either. In conclusion, the combined regimen of CTX and Ara-C represents a promising therapeutic approach to induce the first CR of newly diagnosed adult AML.

Genetic Association of PARP15 Polymorphisms with Clinical Outcome of Acute Myeloid Leukemia in a Korean Population

AIMS

Some members of the poly ADP-ribose polymerase (PARP) protein family have been regarded as targets for the therapeutic inhibition of cancer. Among these PARP genes, poly ADP-ribose polymerase family, member 15 (PARP15) is a candidate gene for cancer development due to its ability to regulate gene transcription and its reported association with apoptosis. The current study investigated the possible association between PARP15 single-nucleotide polymorphisms and the risk of acute myeloid leukemia (AML). In addition, we analyzed the effects of the PARP15 polymorphisms on the clinical phenotypes associated with cytosine arabinose (AraC) chemotherapy in AML patients.

METHODS

Ten PARP15 polymorphisms were genotyped via TaqMan assay in a total of 344 Korean subjects, including 103 AML patients and 241 normal controls. The genetic effects of the polymorphisms on the risk of AML and the clinical phenotypes were analyzed using Statistical Analysis System (SAS) software.

RESULTS

The results from a Cox regression analysis for overall survival revealed that two polymorphisms were associated with increased overall survival and the signal for rs17208928 was retained after correcting for multiple tests (p^corr < 0.05).

CONCLUSIONS

These results suggest the possibility that the PARP15 gene may be a potential therapeutic target in AML patients although much larger scale studies are needed for validation.

Cyclophosphamide combined with mitoxantrone and cytarabine is an effective salvage regimen for patients with acute myeloid leukemia who experienced primary induction failure or relapse

Salvage regimens containing mitoxantrone have been successfully used for the treatment of primary induction failure or relapsed acute myeloid leukemia. However, the combination of cyclophosphamide with mitoxantrone and cytarabine (MAC) has never been assessed in these patients. A total of 91 patients, including patients with primary induction failure (n=44) and relapsed (n=47), were treated with a salvage MAC regimen, which consisted of mitoxantrone, cytarabine and cyclophosphamide. The overall complete remission rate was 74.7 (68/91) and 72.7% (32/44) for primary induction failure, and 76.6% (36/47) for relapsed patients. The overall survival rate and disease-free survival rate were 72.1 and 59.7% at 1 year, 42.9 and 47.1% at 3 years, and 36.7 and 43.0% at 5 years, respectively. Only one patient succumbed to mortality during induction therapy. The toxicity level was acceptable. Therefore, the present study demonstrated that MAC is a highly effective and well-tolerated regimen for salvage in patients experiencing primary induction failure or relapse. This treatment significantly improved the prognosis.

Concentrative nucleoside transporter 3 as a prognostic indicator for favorable outcome of t(8;21)-positive acute myeloid leukemia patients after cytarabine-based chemotherapy

Although acute myeloid leukemia (AML) exhibits diverse responses to chemotherapy, patients harboring the t(8;21) translocation are part of a favorable risk group. However, the reason why this subgroup is more responsive to cytarabine-based therapy has not been elucidated. In the present study, we analyzed expression levels of cytarabine metabolism-related genes in patients diagnosed with AML with or without t(8;21) and investigated their correlation with clinical outcomes after cytarabine-based therapy. Among the 8 genes studied, expression of the concentrative nucleoside transporter 3 (CNT3) gene was significantly higher in t(8;21)-positive patients compared to the others in the test population and the validation cohort (P<0.001 in Mann-Whitney U test; P<0.002 in Pearson's correlation analysis). Additionally, in both multivariate and univariate analyses, t(8;21)-positive patients categorized in a higher CNT3 expression tertile had longer disease-free survival [hazard ratio (HR), 0.117; 95% confidence interval (CI), 0.025-0.557; P=0.008] and overall survival (HR, 0.062; 95% CI, 0.007-0.521; P=0.010) compared to t(8;21)-positive patients in a lower CNT3 expression tertile. Notably, these trends did not occur in t(8;21)-negative patients. Our results demonstrate that CNT3 expression is associated with overall favorable outcomes and is predictive of clinical outcomes in AML patients with t(8;21). This suggests that CNT3 expression can be used to optimize treatment strategies for AML patients.